Bacteria Responsible for Climate Change?

The scientific community is in the midst of one of the strangest controversies. Scientists affirm that climate change is caused by bacteria that use nitrogen and not the carbon dioxide emissions generated by human activities. Did the Intergovernmental Panel on Climate Change (IPCC) fail to take into account a key element in its models?

George V. Chilingar (Department of Civil and Environmental Engineering, University of Southern California) is one of the researchers who support this theory with O. G. Sorokhtin and L. F. Khilyuk. He was an adviser to Ronald Reagan and the United Nations. Moreover, he says that he “advised President George W. Bush not to sign the Kyoto Protocol.” He also states that “George A. Olah, a winner of the Nobel Prize in chemistry, is in agreement with [their] theory.”

O. G. Sorokhtin (Institute of Oceanology of the Russian Academy of Sciences, Moscow)

L. F. Khilyuk (Department of Civil and Environmental Engineering, University of Southern California)

“The hypothesis of current global warming resulting from the increased emission of greenhouse gases into the atmosphere is a myth. Humans are not responsible for the increase in the global surface temperature of 1°F (0.56°C) during the past century and one should explain this increase by natural forces heating the atmosphere,” [1]argue Sorokhtin, Chilingar, and Khilyuk. These authors propose a model that they call the adiabatic theory of the greenhouse effect. According to the latter, “the contemporary global warming, which started in the 17th century (i.e. long before the Industrial Revolution), probably is temporary and determined by the fluctuations in the solar activity.”

This graph, presented by these scientists, is supposed to show the correlation between the temperature change and solar activity.

“Contemporary global warming is developed on the background of general long-term climatic cooling. A new ice age had begun.” In the authors’ opinion, in 400 million years, all continents at moderate latitudes will be covered by glaciers. “At the equatorial belt, the elevated regions will be covered by ice.”This cooling would be caused by bacteria that consume nitrogen, the main constituent of our atmosphere (oxygen represents only 21% of the composition of air). If nitrogen was removed from the atmosphere, this would reduce the pressure of the latter. When the pressure of a gas drops, its temperature decreases—this characteristic of gas is used to generate cold in refrigerators. In our case, this would therefore lead to a cooling of Earth. According to these researchers, past ice ages were also generated by such phenomena related to bacterial activities. Conversely, warmer periods may have been brought about by an increase in atmospheric pressure, for example by an adding of oxygen by plants.

THE END OF LIFE ON EARTH
However, according to this model, in 600 million years, this cold period will come to an end. Oxygen created during the formation of the Earth’s core would no longer be incorporated in the iron contained in our planet’s mantle, the latter being totally “saturated” by this gas. So this oxygen would go in the atmosphere, making its pressure increase. A rise in the pressure of a gas leads to an increase in its temperature (this is the inverse of the case of the cooling of the atmosphere). In this case, the increase in atmospheric pressure would induce our planet’s temperature to rise to 400°C. The situation would continue to worsen: “In 1.5 billion years, the oceans will start boiling.” This would be the end of life on the blue planet.

WHERE IS THE CO2 COMING FROM?
In these authors’ opinion, the rise of the atmospheric carbon dioxide concentration is not the cause of an increase in temperature on Earth but its consequence! According to them, the oceans being the largest CO2 reservoir on Earth—they contain 92 times as much CO2 as the atmosphere—a temperature rise would make carbon dioxide escape from the water and go into the air. The idea is that the warmer a liquid is, the less dissolved gas it can contain. This law can be observed using two glasses and pouring hot water into one and cold water into the other. After a while, bubbles appear on the inner surface of the container that contains the hot water but not on the one with the cold water. These bubbles are made of gas that is “excluded“from the liquid, which can no longer contain it. According to these scientists, in such a situation on Earth, the oceans would therefore release huge quantities of CO2 into the atmosphere.

This graph, created at the Vostok station in Antarctica, charts the parallel change of the temperature and the atmospheric CO2 level. We notice on this chart that the temperature change always precedes the change in atmospheric carbon dioxide concentration.

THE COOLING EFFECT OF CO2
Once this carbon dioxide in the atmosphere, what consequences does it have? According to the Intergovernmental Panel on Climate Change (IPCC) carbon dioxide is a greenhouse gas and therefore induces a warming of the planet. In these researchers’ opinion, this is the contrary: it leads to a decrease in temperature! They state that if our atmosphere were replaced by another one entirely made of carbon dioxide, it would be colder. They reach this surprising conclusion considering that the elements constituting such an atmosphere (the molecules) are 1.5 times as heavy as the ones of air. These ”weighty” molecules have a strong propensity to absorb the sun’s heat by starting to move. These movements of molecules cause the gas to become less dense. This situation can be illustrated by bumper cars; during the night, when they are stationary, it is possible to park them side by side so that they do not take up a lot of room. But during the day, when they move, they use a larger area. It is the same with a gas, which expands once heated. In so doing, it becomes lighter—since it is less dense—and, according to these scientists, rises into the stratosphere, a layer of the atmosphere located between 10 and 50 km. (6-30 miles) above Earth’s surface. It would be a phenomenon similar to that used to operate hot-air balloons. In this case, the air inside the envelope is heated up. The gas expands and so becomes lighter than the one around it. Then it rises up, taking the basket along with it.

In their climate model, once this hot air is in the stratosphere, it cools by radiation, i.e. the heat of the gas changes into waves that go off into space. The hot air, after its ascent into the atmosphere, is replaced by cold air, which is heavier than the surrounding air and therefore goes down. Such movements of air masses are called convection. Thus, in these scientists’ opinion, carbon dioxide has a cooling effect by intensifying these movements.
Another gas that is generally regarded as warming the planet is methane. According to the authors, as in the case of CO2, it would have the effect of cooling the air through the same mechanism.

OTHER SCIENTISTS’ POINT OF VIEW
Regarding the possibility that nitrogen-consuming bacteria could lead to climate changes, Frank Poly, a scientist at the Laboratoire d’Ecologie Microbienne (Laboratory of Microbial Ecology) in Lyon (France), notes that “One must not lose sight of the fact that other theories linking climate to bacteria exist. For example, such microorganisms, also related to nitrogen, produce N2O, a greenhouse gas.” This phenomenon would therefore exert an opposite effect compared to the cooling generated by bacteria according to the mechanism set out by Chilingar, Sorokhtin, and Khilyuk. Bacteria are important in other processes, as in the creation of methane (a greenhouse gas) or dimethyl sulfide, an aerosol that has the curious property of inducing cloud formation. Werner Aeschbach-Hertig (Institute of Environmental Physics at the University of Heidelberg in Germany) works on reconstructions of past climates. He wrote an article in the Journal of Environmental Geology that contradicted the three scientists’ theory. He fears that this has enabled the authors to publish a new article to respond to it. “So I think now that it is better that I ignore these strange theories and concentrate on my scientific work. I don't want to answer questions about these obscure ideas,” he remarks. As for the famous skeptic Willie Wei-Hock Soon, he is also not convinced by the bacterial hypothesis. This astrophysicist at the Solar and Stellar Division of the Harvard-Smithionian Center for Astrophysics in the United States thinks that “The nitrogen-consuming bacteria probably play a role in climate. But is this phenomenon important?” To answer this question, we must go further in understanding the involvement of bacteria in this issue since no assessed estimate is provided in relation to this hypothesis at the present time by the scientists who support it. Nitrogen, carbon, phosphorus, oxygen, and sulfur are necessary for life. Among them, nitrogen has the greatest abundance in the atmosphere and the oceans. The amount of all this nitrogen is larger than that of the four other elements combined. But most of that nitrogen is in the air and cannot be used by the greater part of living beings. That’s where bacteria come in and transform nitrogen that is in the air into other forms that can be incorporated into organisms. For instance, the clover plant hosts such bacteria capable of converting nitrogen into protuberances on its roots.

Clover modifies nitrogen that is in the air. Thanks to this, living creatures like this ladybug can use this element. (Photo: Gius Cescu/http://www.fotocommunity.fr/pc/pc/mypics/979350)

MAN AND THE NITROGEN CYCLE

Since the nitrogen usable by organisms is quite scarce after all, in many environments plants stop developing due to the lack of this precious element. Regarding agriculture, mankind decided to remedy this problem by transforming its useless nitrogen into usable nitrogen in order to give it to cultivated plants so that they can better proliferate. But the quantities of this gas that must be modified through a chemical process (called Haber-Bosch) are such that human beings became a more significant player than nature in this transformation on the continents. This situation has various consequences, notably in terms of pollution. But the one that interests us here is that as the useless nitrogen is taken from the air, 100 million tons of this gas are captured through this process out of the atmosphere each year [2].

“A COMPLETE LACK OF UNDERSTANDING OF THE MECHANISMS”
Does this have an influence on climate according to the model proposed in this theory? It is relatively easy to realize that this is not the case. If we assume that during the past 100 years this amount of nitrogen has been taken out of the atmosphere annually, the total represents only one hundredth of the carbon dioxide added to the atmosphere by the emissions caused by human activities (this is in fact an overestimation for nitrogen since its transformation intensified in the last century). The authors of the theory estimate that the influence of anthropogenic emissions (generated by human activities) of CO2 on temperature is less than 0.03°C. They get this result by calculating the temperature rise according to the change in partial pressure of CO2 due to anthropogenic emissions according to the mechanism described above. Yet they “forget“ to take into account the greenhouse effect! In any event, it is difficult to see how it would be possible for anthropogenic emissions of CO2 to have a negligible effect on climate whereas a quantity of nitrogen at least 100 times smaller can lead to a cooling of Earth by taking into account the same phenomena. When they classify nitrogen-consuming bacteria into the “first-order climate drivers,” which they define as having “an importance 10,000 times greater than anthropogenic emissions of greenhouse gases,” we realize that the mistake is huge. “Changes in partial pressures caused by modifications of the atmosphere composition have a very small effect on climate,” explains Urs Neu, who conducts research on past climates within the Swiss Academy of Sciences. “There is a difference in temperature between the poles and the equator or between day and night even though the average atmospheric pressure between these geographic regions or different times of the day does not change,” continues this scientist, co-author of the book Climate Variability and Extremes during the Past 100 Years. Taking nitrogen up from the atmosphere does not significantly influence the Earth’s temperature, as this element is not a greenhouse gas. Gavin A. Schmidt, a climate modeler at the NASA Goddard Institute in New York City, agrees with this point of view and considers that the scientists who have put forward this hypothesis show “a total lack of understanding of the way the atmosphere works.”

CO2 AND CLIMATE
The bacterial hypothesis is not the only one formulated by Chilinar, Khilyuk, and Sorokhtin. What should we think about the idea that CO2 has the effect of cooling the atmosphere? Is the mechanism set out above real? Let’s recollect the theory: CO2 absorbs heat and so expands, becomes lighter, and rises into the stratosphere, where it cools by radiating out into space. Once cold, it descends in the atmosphere and refreshes it. “One of the problems with this theory is that a heated air parcel rises only if its temperature is higher than the one of the air that is around it,” explains Urs Neu. This is indeed what we saw in the example of the montgolfier: it rises up because the air is hotter inside the envelope than around it. “Because CO2 is relatively evenly distributed throughout the atmosphere, the warming due to the heat absorption of CO2 occurs everywhere.” adds the researcher. Given the fact that for convection phenomena to take place there must be parts of the atmosphere that are warmer than others to have mass differences, in such a case these air movements are nonexistent. Even if the convective processes described by the authors were real, hot air could not go to the stratosphere and cool there. Indeed, one might imagine intuitively that the more one goes up into the atmosphere, the more its temperature decreases. This is in fact not the case. The stratosphere is warmer than the top of the layer beneath it, the troposphere (inside which we are). “Because of that, convection phenomena cannot go through the boundary between these two layers,” underlines Urs Neu. Warm air arriving at this layer is colder than the surrounding air, so it is heavier than the air around it and stops its ascent.

OCEAN DEGASSING
We now come to the last point of this theory: is the rise in the atmospheric level of carbon dioxide caused by the ocean degassing resulting from the increase in temperature? Many factors lead to the refutation of this hypothesis. Techniques (isotopes C12/C13, radiocarbon) permit scientists to determine if the carbon is of natural origin or generated by combustion. One knows, thanks to these studies, that the increase of the atmospheric concentration of carbon dioxide is anthropogenic. The acidification of oceans, which is due to a rise in the quantity of CO2 that they contain, is also an indication pointing in the same direction. Furthermore, reconstructions of past climates carried out at Vostok Station in Antarctica (see graph above) show that in the transitions between glacial and interglacial periods, a temperature increase leads to a rise in atmospheric CO2. There is an 800-year latency between these two events. It is therefore not possible that the warming induces an increase in the atmospheric CO2 level in the current climate change. The authors also do calculations using Henry’s law, a physical law that allows connecting the concentration of a gas dissolved in a liquid and the pressure of this gas in the air. This leads them to the conclusion that CO2 has leaked out of the oceans, which would be consistent with the hypothesis of degassing. Yet only temperature variation is taken into account and not the change in the partial pressure of CO2. By introducing the latter, one can reach the opposite conclusion (depending on the chosen temperature). In addition, Urs Neu draws attention to the fact that Henry’s law is not valid for such considerations. “Many other processes and factors play a role in such a question. For example, there are colder areas in the oceans that can contain a lot of carbon dioxide. This cold water, denser than the one that surrounds it, will then descend into the ocean and therefore remove CO2 from the atmosphere.”

Yet even assuming that the calculations made by the scientists supporting the idea of degassing (using a temperature change of 1°C) are right, their own result contradicts their theory. Thus they come to the conclusion that the CO2 released by the oceans has induced an increase of 13.5 ppm (parts per million, unit of concentration) in the atmosphere. This would only explain a fraction of the actual rise, which is of 100 ppm. Among the first-order climate drivers also appear, according to Sorokthin, Chilingar, and Khilyuk, variations in solar activity. They justify this point of view with the graph correlating solar activity with the temperature on Earth (see above). Two scientists, Eigil Friis-Christensen and Knud Lassen, published a chart similar to the one presented by these researchers in the scientific magazine Science in 1991.

The 1991 graph. In blue: solar activity. In red: the terrestrial temperature.

Part of the scientific community remained skeptical of this paper. The reason for this was that some thought that the statistical treatment used had the effect of distorting the curve of solar activity for the recent periods. In 2000, new information permitted scientists to determine that the graph was wrong.

The corrected chart of 2000. Note that the correlation between solar activity and temperature no longer exists for the recent period of the curve.

Gavin A. Smith, who was named as one of the 50 leaders in science on a global scale by Scientific American magazine, thinks that “These authors’ theory does not make sense. It’s equivalent to writing a book about gravity and assigning all the effects to the sucking of a hypothetical giant turtle.”

                                                               Gaëtan Dübler

[1] The quotations in this part come from the book Global Warming and Global Cooling, Evolution of Climate on Hearth published by Elsevier and authored by the three above-mentioned scientists.

[2] For more information about the nitrogen cycle and man's influence on the latter, see for example Galloway et al., 2003, 1995; Burns and Hardy, 1975; Jaffe, 1992; McElroy et al., 1976; Schlesinger and Hartley, 1992; Stedman and Shetter, 1983; Söderlund and Svensson, 1976; Mackenzie, 1998.

Al Gore Thwarted by Historians!

Is it true that our world is becoming chaotic because of climate change, as shown in Al Gore’s documentary An Inconvenient Truth? Are climatic extremes increasing today? What did past climates look like? Scientists think that the IPCC (Intergovernmental Panel on Climate Change) has been wrong on these issues. Depart on an amazing journey through time and ancient civilizations.

Yale University, United States, 1964: At the foot of the Harkness Tower, ferocious gusts of wind formed deep snowdrifts. According to legend, this building is the largest ever built of stone. There were icicles on the Aristotle, Euclid, and Shakespeare masks and statues, and from time to time members of campus secret societies crossed the park, going to meetings of their bizarre cults (Yale University is known for such groups, including Skull and Bones which have included among others both presidents Bush. This institution is also known for the education of this nation’s elite). These blurred silhouettes seemed at times to disappear in waves of wind and snow coming from the sky. When they were visible again, some were turning up the collar of their coat.

AN AMAZING DISCOVERY
Farther in the park, a porch could barely be made out, with steps indistinguishable in the snow and flanked by two lanterns forming a halo where snowflakes could be seen blowing in all directions. Above it, a man came and went in a room behind an illuminated window. He sat at his desk and took one of many tablets bearing cuneiform inscriptions piled around him. Running his hand delicately over the clay to remove a few grains of sand from a distant country, he recalled the story of its discovery. In 1933 in Syria, men wearing turbans and long coats, accompanied by camels, walked to a mound to bury a deceased Bedouin of their tribe. They began to dig and discovered a statue. When the French authorities, who were then in control of this nation, heard about it, archaeologists from the Louvre came to this site. Soon a temple was discovered, and then a whole city, that of Mari. In a palace with more than 260 rooms, 20 000 of these cuneiform tablets were found.The Professor of Assyriology and Babylonian literature at Yale University, whose name is William W. Hallo, then immersed himself in the mysterious succession of signs impressed by a hand four millennia ago (deciphering of cuneiform script has been known since 1851). Deciphering symbol after symbol, he soon realized that he had made a sensational discovery. The text recounted the itinerary of a trip in Mesopotamia (a geographical area between the Tigris and the Euphrates rivers, corresponding to present-day Iraq as well as parts of Syria, Turkey, and Iran. It was here where the first civilizations appeared, including the Sumerian, Babylonian, and Assyrian empires, between the 5th millennium and the 6th century BC). The text mentioned the capital, Tell Leilan, of a country whose existence was known only thanks to tablets that had been found in the ancient city of Babylon. It also indicated the distances between various points of a journey. Converted to a modern map, this itinerary permitted determination of the spot where this city, buried beneath the sands, should have been situated. But some archaeologists had doubts about its existence. "At the time nothing was definite,” remembers Harvey Weiss, a specialist in Middle Eastern civilizations at Yale University. Yet, in 1978, this archaeologist traveled to Syria, to the place indicated on the map by the text found in Mari. He started digging in a mound located between two trails and discovered a temple with columns magnificently decorated, and then found another. Later he found a 15 meter (50 foot)-high and 18 meter (60 foot)-thick surrounding wall. In 1981, Dr. Weiss explained to a New York Times journalist that he "hope[d] to finish the excavation by next summer" [i]. Since then decades have passed and the paper of the article has yellowed. But the archaeologist is still on his Tell Leilan site. The reason is that the site had yet to reveal secrets before Harvey Weiss could leave it. His excavations have shown that this city was suddenly abandoned. What prompted its inhabitants to move? The same appears to have happened in other cities of this Akkadian empire, which then collapsed.

THE EGYPTIAN EMPIRE TURNED TO ANARCHY

Even more disconcerting: the Old Kingdom of Egypt, which had built the pyramids, turned to anarchy at the same time as other civilizations in Palestine, Greece, and Crete. All reached their economic peak in 2 300 BC and then disappeared. "That was very strange. How could societies with different organizations and political structures all suffer the same fate at that particular time? Only an element having an interregional, hemispheric power could explain such a situation," says Harvey Weiss. He then looked for the cause of this situation. Soon clues started piling up; a drought was so severe in this region that even earthworms did not survive, as shown in analyses of soil samples. "In terms of strata, there is a layer of wind-blown dust in Tel Leilan as well as at many other places. This is a sign indicating dry soils and therefore a drastic rainfall reduction," adds this professor. Studies of pollen also point to a transformation of vegetation to plants adapted to arid conditions. "In Egypt, a decrease of 30 to 40% of the flow rate of the Nile River is observed, thanks to research conducted at both ends of this river,” explains the archaeologist. Indeed, this is the conclusion of studies of both the Nile River delta and East African lake levels, which constitute its source. Southern Mesopotamia was less affected by the drought thanks to its irrigated agriculture. There was an influx of climate refugees to this area. In an attempt to control this immigration, the empire built a wall 180 kilometers (112 miles) long.

A CURIOUS NASA REPORT
A NASA report about climate change and its implications for U.S. national security predicts that the United States will one day have to build such fortifications to hold back refugees [ii].

According to this document, important climatic modifications would cause food, water, and energy shortages. As recalled by archaeologist Steven LeBlanc of Harvard University, United States, from time immemorial, humans have engaged in warfare to obtain these elements.These conditions would quickly plunge China into serious political instability. Bangladesh would be uninhabitable. As a result of sea level rise, fresh water would be contaminated by salt water. A massive migration would take place, causing tensions in China and India as well as aggressive wars to obtain food, water, and energy. As predicted in the NASA report, in 2015 Russia and China would sign strategic agreements concerning energy resources in Siberia and Sakhalin (a Russian island, covered by forests, located in the Pacific Ocean and having significant oil, coal, and gas resources). In 2018 China would intervene in Kazakhstan to protect pipelines regularly attacked by rebels and criminals. In 2020 Europe's climate would be similar to that of present-day Siberia, and famines would start (in this report, the authors speculate that climate change could cause the disappearance of the Gulf Stream, an Atlantic Ocean current. This would lead, in their view, to cooler European climates).

"IN 2025, THE EUROPEAN UNION NEARS COLLAPSE."
The NASA report projects that in 2025, the European Union will nearly collapse. Chinese internal conditions will deteriorate dramatically, leading to a civil war. Chinese and U.S. naval forces will be in direct confrontation in the Persian Gulf. Australia and the United States would build defensive fortresses around their countries to protect them from starving immigrants from the Caribbean islands, Mexico, and South America. The United States and Canada would ally, the two countries becoming one. Nuclear weapons would proliferate. Pakistan, India, and China—all armed with nuclear weapons—would skirmish at their borders over arable land, a situation that could degenerate into even more disastrous war scenarios for humanity.But let’s go back to antiquity. Other societies have collapsed as a result of climate change. Four hundred years after the end of the Akkadian civilization, the same happened to the Tiwanaku civilization in the Andes. The reason again was lack of rain. The level of Lake Titicaca, located in this area, dropped by 10 meters (33 feet).The collapse of the Mayan civilization in the 9th century AD coincides with the longest and most severe drought of the millennium. The droughts related to these civilization collapses were more important than those that happened during the 19th and 20th centuries.

THE CLIMATE SINCE YEAR 1000

The stone here, far from representing its weight, expresses vertical momentum in columns that seem too light to bear the huge weight of the vaults suspended at dizzying heights. Through the stained glass windows, rays of light, made visible by specks of dust in the air, create colored patches of light on the floor. Men, seemingly tiny in this architecture of spectacular size, are now lifting onto their shoulders a support bearing a Black Virgin statue. The procession leaves the church, going from cool air to the scorching heat of the summer, from the shadowy light to the blazing sun, the penitents suddenly splashed by light. The clerics, wearing cassocks and richly ornamented cappa magna and holding banners and crucifix, which seem to sparkle in the sun, walk in front of the faithful. The procession crosses the town, arrives in the country, passes between fields with crops destroyed by the drought, and then arrives at the seaside. There, the Virgin statue is delicately lowered from its support and churchmen carry it to the water before bathing it. This is one of many French processions carried out during the Ancien Régime (period before the revolution) to satisfy the wrath of God, which was seen as the cause of extreme weather events. Other means were used, including prayer and witch hunts. Despite these efforts, the archives of this period mention many floods, with bridges swept away, and avalanches crushing houses. The most sophisticated database in the world in this domain exists in Switzerland. Named EuroClimHist, it contains more than 1.5 million entries. France is also in the process of establishing such a resource within the framework of the RENASEC (Les REfus de la NAture. Sociétés et Extrêmes Climatiques: Refusals of Nature. Society and Climatic Extremes) project. The documents dealing with climate information are listed, including harvest dates (grapes, hay, etc.), meteorological processions just described, and temperature measurements taken by the Paris Observatory since 1656. Sunspot variations are also taken into account, the latter reflecting activity of the sun. In France, departmental, municipal, and national records are sifted. "The registers of municipal deliberations are particularly useful," notes Emmanuel Garnier, the historian assigned to the OPHELIE (Observations PHEnologiques pour reconstruire le CLimat de l’Europe: Phenological Observations for Reconstructing Europe's Climate) and RENASEC projects.

The historian Emmanuel Garnier

Indeed, these documents were begun in 1450 and record, among other information, the weather. "It is because meteorological events have an economic impact. For example, in the case of drought, there was less water in the rivers, which means that it was no longer possible to use mills equipped with paddle wheels. So the grinding process halted and therefore flour was no longer on the market. Then, there was a risk of riot," continues the researcher. Administrative sources are also used, such as those concerning the bridges and roads, the forestry commission, and the navy. As part of the OPHELIE project, private individuals were also asked to send their own records related to climate. "We received many copies of diaries referring to climatic events,” remarks Emmanuel Garnier. These diaries were sometimes kept for 50 years (several members of a family would take turns making entries). In Switzerland, monks’ diaries have been searched. Another example of documents used by EuroClimHist are records of Stockholm’s port that exist from 1543 to 1893. As they indicate when a vessel entered or left the port, it is possible to deduce from them the periods during which the port was frozen.

"THERE WERE MORE HURRICANES IN THE 18TH CENTURY THAN DURING THE 20TH."
It would be wrong to imagine, as suggested in An Inconvenient Truth, that the Earth's climate has only recently been affected by extreme events because of global warming. Dr. Christian Pfister, a climate historian at the University of Berne in Switzerland, who has set up the EuroClimHist database, notes that "the largest Rhine River flood during the second millennium occurred in 1342. All the bridges were destroyed, and in Frankfurt the water surface was at roof level, 7 meters [23 feet] higher than the second most important flood in this area! "

Dr. Christian Pfister

The coldest winter during the last millennium occurred in 1364. "There was a 4-meter [13-foot]- thick layer of ice on the Rhone River," says the professor. Year 1473 was the hottest and driest during this millennium. "The conditions were such that all trees shed their leaves in August,” continues the historian. Hurricanes are also events that took place in the past. For example, in 1999, the French, Swiss, German, and Danish forests were devastated by a hurricane called Lothar. A very similar phenomenon happened in 1739 with about the same route and barometric pressure (measured at the Paris Observatory). In France the Fontainebleau castle was damaged, roofs were swept away, and trees fell. In a forest in Mulhouse 8 000 oaks collapsed. "To state that history repeats itself corresponds to a reality about the storms," says Emmanuel Garnier. While the idea of an increase in the number of storms as a result of global warming is often presented in the media, or even that storms are a very reliable climate change indicator, this professor thinks that "these assumptions are wrong. For instance there were more storms and hurricanes in the 18th century than in the 20th!” Christian Pfister confirms that "The past century is atypical by the fact that, in Central and Western Europe, few extreme weather events have occurred compared with other centuries." On the idea that the damage generated by the environment is more important today, Emmanuel Garnier thinks that "in many cases it was not climatic risk that increases but vulnerability." The concept explained in Al Gore’s documentary film that the climate is changing is not new. For example, in the 1820s–30s, the French mountains were less snowy. "There was then a consensus comparable to the present one, including official speeches, stating that there would be a disruption of the seasons, winters with less snow," notes Emmanuel Garnier. The climate change issue has been in vogue at other times, for example, during the 16th and 17th centuries. "We must be wary of the popular sense, because people forget climate history very quickly. After 20 years, a climatic catastrophe is blotted out. For example, few people today remember the 1976 heat wave!"

"IT WAS POSSIBLE TO CROSS THE RHONE RIVER ON FOOT"
Regarding violent weather events, if these studies do not confirm what one would have expected, another point is also disconcerting: temperature change. ”When I started my research, the view was that the last 500 years were marked by the Little Ice Age, i.e., a cold period that would have lasted from the early 14th century until 1850," explains Emmanuel Garnier. While he noticed cold periods, as shown for instance by the fact that the Seine and Rhone rivers froze, he also discovered very hot times with droughts. In 1480 in Lyon, the population was parched and died of heatstroke because of such a weather event. “The body of artisanal trades was decimated. A doubling of mortality was recorded from August to September while it was possible to cross the Rhone on foot,” observes the researcher (The Rhone is one of the major rivers in Europe). From 1705 to 1725 there were also scorching periods and terrible droughts lasting four or five months in the Paris region. In Languedoc-Roussillon (a region in southern France along the Mediterranean Sea) they lasted for one to two years. "These are phenomena similar to those seen today in the Sahel with problems of access to water and a desertification of the country," adds Emmanuel Garnier. This led to displacement and ethnic conflicts. For example, in 1612 in Narbonne, a city situated in the Languedoc-Roussillon, the Berber community—native to northern Africa—was accused of being the cause of a drought by generating the wrath of God before being expelled to Africa by boat.

"OUR VIEW OF PAST CLIMATES WILL HAVE TO CHANGE."
Christian Pfister confirms this point: "Our view of past climates will have to change. The IPCC (Intergovernmental Panel on Climate Change) reconstructions are based among others on dendrochronology(the study of patterns of growth of tree rings. For reconstructing past climates, it is estimated that the more the trunk grew between rings, the warmer it was). This technique gives information only about the time during which plants grow, i.e., 30–40% of climatic variation during a year. If one also has data for cold seasons, climate reconstruction will be different. "For example, in Western and Central Europe, the 12th century was warmer than what these curves show," adds Professor Pfister. We address the much talked-about controversy of the hockey stick, MBH 99. MBH is an abbreviation for the names of the three scientists who developed this curve, and 99 stands for the year of publication in the scientific journal Nature. In 2001, MBH 99 was included in the 3rd IPCC report, before being brought into the limelight.

The curve developed by Michael E. Mann et al. and published in Nature in 1999(MBH 99). The black curve shows 50-year average temperatures. The fluctuations around it are yearly temperatures. The grey region containing the curve represents the intervals in which real temperatures have a 95% chance of occurring. The red shows measurements by instruments (as opposed to temperature reconstructions).

MBH 99 as presented in the media, here from the front page of an important French daily dealing with economic and financial issues and published last year. Note that the graph ends in 2000. If we extrapolate this curve for 2009, it shows very hot temperatures...

Various criticisms, mostly unfounded, have been leveled against it regarding the statistical techniques used, the validity of some series resulting from dendrochronology, the number (deemed to be too low) of series used and their geographical distributions (sometimes described as not representative of the Northern Hemisphere).

Christian Pfister summarizes his views: "The MBH 99 curve probably has parts that do not represent actual temperatures for different times. The authors did not have the data necessary for such a study.” Other scientists have other opinions. For instance, Dr. Philip D. Jones, a climatologist at the University of East Anglia in the United Kingdom, who modeled curves similar to MBH 99, thinks that "new information will not significantly change our conclusions about past climates.” For this IPCC member, it is rather the use of archives about which one has to be wary: "The problem with these sources is that they tend to focus on the extremes but not on the small differences in average conditions.” He admits, however, that there may be questions regarding the quality of the data used in these reconstructions. "We must be careful about how we put datasets together, not only for surface measurements and weather balloons, but also for satellites.” Indeed, the latter are not designed to study variations over several decades because of changes in measurement instruments that have occurred over the past 50 years. For satellites, their orbits degenerate (i.e., they get closer to Earth) so they observe different parts of the globe during their rotation as time goes by. "Paradoxically, all these improvements, including the observations from space, create many problems," comments Dr. Jones.

"THERE ARE ALSO FINANCIAL ISSUES"
This controversy has also brought up another issue about studies of past climates: who can have access to the data? Though in science all information is normally made public so that other researchers can verify results, in this domain this policy is not necessarily implemented. For example, regarding temperature reconstructions for the last 1 000 years, two scientists, Warwick Hughes and Steve McIntyre, had difficulty obtaining the data from the scientist who had modeled the curves in question, Professor Philip Jones. He argues that it is not the universities’ role to make such data available before explaining that "[he] signed agreements with countries that stipulate that [he] would not give such information to third parties. Most European nations have restrictions on such dissemination of data." This is not the only case where scientists have had such problems. French researchers are struggling to access information from the EuroClimHist database. For his part, Christian Pfister explains that he invested 20 years of work in this study as well as personal money. "I want this to be credited to me within the framework of scientific publications," he remarks. As noted by Professor Garnier, there are also economic issues behind such information. "Insurance and reinsurance companies seek information for estimating the costs they will have to bear for damage generated by climate change.” (A reinsurance company acts as insurance for an insurance company. It guarantees a certain sum of the risk borne by insurance companies for a percentage of their premiums. This allows insurance companies to assume risks beyond the financial capacity covered by their funds and to avoid having to pay all the damages they insure in the case of a serious disaster and therefore to avoid bankruptcy in such a situation.) Yet this historian has decided that ''his'' database will be made entirely public, so it will then be possible for everyone to see past climatic extremes, for example, for the region where he or she lives. (I will give the link for the site of the database once it exists).
The criticisms expressed by these historians in relation to MBH 99 and changes in violent weather events do not mean that they are questioning the fact that the present climate change is a reality. Professor Pfister emphasizes that the past changes he observes are different from those he sees now: "In the Middle Ages, during warm periods, important changes often happened during the summers and winters, with colder and damper weather than today." In relation to antiquity, Harvey Weiss thinks that it was also different from the present situation. "These changes involve modifications in precipitation. Currently, there is an increase in temperature that is causing problems in terms of melting ice and rising sea levels. The current change is unique in the history of mankind. It is a frightening element."

AND THE FUTUR?
Beyond satisfying our curiosity to know about past climates, what's the point of such studies for our society? What makes these events interesting is that they document the resilience and vulnerability of large complex civilizations to environmental variability. Such societies have the capacity to cope with such problems, but they cannot adapt indefinitely. After a certain point, the established order collapses to make way for a new organization more in line with the new climate. "Climate changes forced the reorganization of many political structures," notes Harvey Weiss. We saw above that different societies, including the Mayans and the Egyptian Old Kingdom, collapsed when climate changes took place. More recent examples also exist, like the French Revolution. Spring 1788 was extremely hot, and thunderstorms devastated much of culture of the kingdom of France. "The consequences of this situation left a mark on the market from May, during the soudure, i.e., the transitional period between old and new crops. The Estates General was assembled by the king of France in 1789 to deal with the issue of a better representation of the people in politics. Its results were considered unsatisfactory, as evidenced by popular events linked to the high cost of wheat. Women marched on Versailles, taking by surprise the National Guard (police headed by Lafayette as commander in chief) and the National Assembly’s elected representatives (established during the Estates General, the National Constituent Assembly took as its mission to provide France with its first constitution). They were hungry and wanted food for themselves and their children," explains historian Emmanuel Garnier. Lafayette tried to contain the crowd and forced the king to return to Paris. Once the sovereign in the capital, this had the effect of significantly weakening his power, in that he was continually threatened by the riot, and this contributed to the collapse of the monarchy. Philip Jones also points out that the Vikings did not survive in northern and western Norway in the 14th and 15th centuries, probably because they failed to adapt to colder temperatures. Finally, the dinosaurs are not absent from this pattern! Alongside the famous meteorite hypothesis, another states that a colder period could have led to their extinction. "Humanity will have to adapt quickly, because climate change will certainly take place in the future faster than it did in the past. We should take this into account when designing buildings, crops, etc.," considers Dr. Jones. Renaud Crassous, a researcher at the Centre International de Recherche sur l’Environnement et le Développement (International Center for Research on Environment and Development) in France thinks that "In twenty years Earth will be affected by famines. We do not currently have sufficient stocks of food to cope with a climate change." Christian Pfister also observes that the worst impacts on populations occur when the change is not anticipated. "A climate change can happen very quickly, as was the case around 1300, when a colder climate suddenly settled. Our societies should have a greater safety margin in anticipation of such events. We are not currently ready." In the future three interdependent problems will arise: food, water, and energy shortages. “In addition, the price of fossil energy will increase. It is a very dangerous situation for a society,” continues the researcher. As for Emmanuel Garnier, he thinks that history has a role to play in the establishment of adaptations for land use, buildings, roads, etc.: "During the Ancien Régime, there were urban areas that were used for absorbing and spreading the floods. This no longer exists today," he remarks. Observer networks were set up, for example, upstream of a river to announce a flood. "In Lyon, debacles were feared when there was a very harsh winter because of pieces of ice coming from the Rhone Glacier in Switzerland. There were observers in the Alps who warned the city. Bridges peopled with residents and merchants were evacuated," he continues.

THE FUTURE: BACK TO THE PAST?
What will be the consequences of climate change on our societies? Emmanuel Garnier thinks that it could lead to organizations similar to those that existed in Europe during the Middle Ages! At that time disasters were taken care by religious aid, with secular payment beginning in France in 1650. Although the king was officially a Christian, being crowned in Reims by the pope, he gradually marginalized the Catholic Church. This occurred through specialized administrations that led investigations and paid compensations directly to the disaster victims. Gradually, climatic risk was no longer seen as a manifestation of the wrath of God but as a rational phenomenon that can be anticipated and handled. "Helping victims is a way to show that there is a central power and that it is better to rely on it than on local or religious authorities," explains Dr. Garnier. “This is a view that the United States’ federal government dropped beginning in the Reagan era. About Katrina—a hurricane that raged in the United States in 2005, where the most serious consequences were in New Orleans, Louisiana, which was then flooded—I was appalled when I saw the following scene: after 5 days, military trucks arrived with pastors from Christian fundamentalist sects. Instead of food they distributed bibles! The message was: if this area is flooded, it is because you are being punished by God. The interest for the central power is not to investigate climatic risk." For this scientist this is a turning point that also begins to emerge in France. "While in the 15th century there were flood markers, this practice has now been partially given up. As there is no flood marker, it is a way for the state to off-load the blame on elected representatives and owners in case of disaster." In his opinion, such a situation would lead the population to withdraw into their own communities, leading to a new social organization characterized by population segmentation, where individuals recognize only the authority of a small minority or group of people. At the level of nations, a lack of international solidarity could lead to regional wars motivated by the instinct of self-preservation. To put it bluntly, it would mean the return of societies similar to those of the Middle Ages. Knowing that these societies were also characterized by hunts for scapegoats, such as so-called witches, this situation can only send a shiver down the spine!
In terms of the energies used, this could not be more glorious. While one often speaks about trendy alternative energies such as wind turbines and solar panels, Hubert Kieken, a scientist at the Institut du Développement Durable et des Relations Internationales (Institute of Sustainable Development and International Relations) in France thinks that ”If there were no more oil in 10 years, the solution to the energy problem would be coal. It is possible to use this fuel to operate power plants and heaters and one can even create oil with it through a process called Fischer-Tropsch!” For this researcher, coal will retain a dominant share nuclear power in the next 50 years. The reason is that one needs to be able to quickly provide huge amounts of energy, for example, for China. The idea to use essentially nuclear energy in France works because this country is surrounded by nations with a different development pattern for their nuclear facilities. Thus France can export electricity to neighboring countries most of the time and import it during the winter. "This example is not reproducible on a large scale in other conditions. Moreover, with the current generation of nuclear power stations, we would soon face the problem of uranium depletion," concludes Dr. Kieken.

Gaëtan Dübler

[i] "Diggers Find Imperial City of Assyrians." The New York Times. October 18, 1981.

[ii] For more information, see http://oco.jpl.nasa.gov/pubs/Abrupt_Climate_Change_Scenario.pdf

Collective Intelligence is Thwarted by the Climate Change Issue

Mark Klein is one of the scientists leading the Climate Collaboratorium project at MIT (Massachusetts Institute of Technology) in the United States. For more than a quarter of a century, he has studied man’s collective intelligence. Interview:

-Climates: Collective intelligence is not perfect and can lead to grave errors, as was the case with the space shuttle Challenger disaster. Collective decisions can even be less shrewd than individual decisions. How is this possible?

- Mark Klein: Mainly three factors can lead a group to an erroneous decision: 1) information on the situation is not taken into account because of social or political pressure; 2) points of view that have been expressed early in the deliberation process can have a disproportionate impact on the final outcome, eclipsing more accurate or useful contributions that came later. Indeed, people will have the feeling that a commonly accepted view is right and that it is therefore not necessary to investigate it. 3) Groups have a tendency to polarize, i.e. to uphold more and more extreme opinions. These error amplifications are due to the fact that humans tend to believe that an affirmation is true if a large number of persons purportedly do so. The rationale typically is: “how can all these people be wrong?”Social pressure also plays a role. It is determined by peer influences such as fear of conflict, fear of being ridiculed or marginalized by the group. Then the individual becomes servile vis-à-vis his superiors in an opportunistic attitude. He hopes by this means to satisfy his desire to be part of a community with which he shares a common outlook on reality. In this way, he creates a social identity for himself in feeling to be part of a clan. Members will then adopt a shared ideological approach and will mutually reinforce their views. These two phenomena lead to conformism. Its result is that it is no longer possible to explore a large enough number of solutions. The group then makes a decision very quickly. In these conditions, the probability that errors will spread and that the group will come to bad decisions increases significantly.

-C.: Are these factors at work in the climate change debate?

-M. K.: Yes. About this theme, one can for example observe the phenomenon of conformism generated by social pressure we have just discussed. To illustrate this point, one can take the case of the individuals who think that climate change will not have problematic consequences for humanity. They are essentially in contact with people who share the same opinion. This will have the effect of reinforcing their point of view. We encounter the same situation with those who consider that climate change will cause a disaster. Although the work done by the scientific community is of good quality, we see as regards the political sphere and the media that the interactions about this issue are incoherent and dispersed. There is no clear way to converge on well-supported decisions concerning this problem. A worrying point is that the information on climate change is essentially transmitted by the media, whose purpose is not to concentrate on science but on stories likely to capture the reader’s attention. Globally, what one witnesses is the failure of collective intelligence faced with this problem!
It is for this reason that we're developing a new type of highly sophisticated discussions and forums on the Internet at MIT (Massachusetts Institute of Technology). Called Climate Collaboratorium, they will improve the quality of the decision-making process primarily with regard to climate change. The idea is to use computer technology to harness collective intelligence, i.e. to create channels enabling the accumulation and the synergy of the vast human and technological resources for decision-making purposes. In other words, it will permit people of all backgrounds to state their opinion. It will be possible to compare the latter and the arguments that underlie them. In this way, we will have a wider range of views than anywhere else.
We have just completed a real-life deployment of this system to test it. This experiment took place in Zurich (Switzerland). We worked with 300 students divided into 3 groups. One used the Collaboratorium, whereas the two others employed other collective intelligence tools. We are currently analyzing the results.
The Collaboratorium will allow us to go beyond the Intergovernmental Panel on Climate Change’s (IPCC’s) work, listing thousands and thousands of ideas. In the long run, the goal is to create an electronic democracy that would exceed our present means, which only enable the citizen to vote yes or no about small numbers of simplified alternatives. This system would make reasoned collective decision-making about highly complex issues possible.

- C.: Is the democratic system the most appropriate to deal with the issue of climate change?

- M. K. Yes, democracy is conducive to grasp complex problems. The reason for this is that it employs a vast number of brains in the consideration of an issue, which is not the case for hierarchical systems. On the other hand, monarchies and dictatorships are more effective for the resolution of simple but large-scale sets of problems.

- C.: Could the Collaboratorium become challenging depending on the conclusions that it reaches?

- M. K.: Yes, there are people who benefit from the fact that questions are not asked. This allows them to restrict the debate to the options that they prefer. The Collaboratorium will come into direct conflict with them.

- C.: Ants have a great collective intelligence. In biology, one even uses the notion of superorganism to refer to the different ants of a nest interacting. Are they collectively smarter than humankind?

-M. K.: Yes. A great collective intelligence means that the community is a lot smarter than the individuals who make it up. In these insects, the colony is remarkably intelligent, but this is not the case for individuals taken separately. This results from simple but well-thought-out rules that these arthropods follow in their interactions. In mankind, this is the opposite: human beings are intelligent, whereas society is globally stupid. Regarding this, MIT is in the process of developing measures of collective intelligence quotient for the global brain, as is the case with IQ (intelligence quotient) for individual brains. In the future, this innovation should allow using effective organizations according to the kind of topic that one wants to treat and the available resources. Such a development will of course also apply to the climate change problem.

Gaëtan Dübler

What the Dinosaurs Have to Teach us about Future Climates

This reptile is a Diplodocus. With a length of up to 35 meters (115 feet) and a neck alone measuring up to 9 meters (30 feet), it hatched from an egg measuring 20 to 30 centimeters (8 to 12 inches) in diameter. It is estimated that its heart weighed 1.6 metric tons (1.8 short tons), unless there were auxiliary pumps in its neck. Similar herbivores, even more disproportionate, weighted about 80 metric tons (88 short tons)!

What will Earth look like if the atmospheric concentration of CO2 continues to rise as a result of emissions generated by human activities? The answer lies in a world long gone, the world of the dinosaurs. Indeed, this era was characterized by an atmosphere containing up to 12 times as much carbon dioxide as today and therefore by a considerable greenhouse effect; thus the study of that era is very important for developing realistic scenarios of what can happen in the future. It also makes it possible to test the climatic models used to predict future climates. Climatologists today work with paleontologists. What can we learn about our blue planet’s future from fossils that have been buried under the ground for hundreds of millions of years?

Bettles Airport, Alaska: A U.S. Army CH-47D Chinook helicopter has just landed to fill up with kerosene. The pilots take the opportunity to once again examine the satellite photographs of their destination. The aircraft and B Company, 4th Battalion, 123rd Aviation Regiment, whose soldiers form the crew, prepare for one of the most difficult missions since the Viet Nam war. The objective is to recover a marine reptile fossil, an Ichthyosaur, that lived during the dinosaur era in the Arctic Circle.

Reconstruction of Ichthyosaur.

The stopover complete, the flying machine heads north. Once arriving at the fossil site, the crew sets up camp. There is no road or home within 200 km (124 miles). Army representatives, accompanied by scientists and headed by an expert on polar dinosaurs, Dr. Gangloff, extract the fossil and protect it for transport. Despite difficult weather conditions, on the fifth day the precious stone is hoisted aboard the helicopter under a sun that never sets at these latitudes at this time of year.

The fossil collected during this operation.

Shortly after this expedition is completed, a similar one is arranged.

Members of the second trip.

Chinooks, equipped with skis for landing, flying over the Arctic Ocean toward their new goal.

This time, the expedition brings back different dinosaur fossil specimens, including three Pachyrhinosaurus skulls weighting a ton.

Young Pachyrhinosaurus dinosaur. Once adult, this herbivore was about 5.5 meters (18 feet) long and 2 meters (6.5 feet) high.

Why so much effort to transport the skeletons of creatures extinct since antediluvian times? One reason is that studying them provides indications of the climate that reigned on Earth at the time they lived. For example, it is surprising to realize that dinosaurs lived in the Arctic Circle, which is an inhospitable region today. This suggests to paleontologists that a very different climate existed there than at present. Because CO2 levels during the Mesozoic Era—the period when the dinosaurs lived—were up to 12 time higher than they are today, this period permits study of a world characterized by an important greenhouse effect, perhaps similar to the one created by humans by use of fossil fuels that produce greenhouse gases by combustion.

THE MEMORY OF PLANTS
How do scientists know the atmospheric levels of carbon dioxide existing tens of millions of years ago? One way is the study of magnolias! If these plants are exposed to significant levels of CO2, the shape of their leaves becomes different. Since magnolias existed at the time of the dinosaurs, scientists can look at their fossils and deduce from them the concentration of carbon dioxide when these plants were alive.

A magnolia flower. Because these plants first appeared before bees even existed, their flowers evolved to be pollinated by beetles! (Beetles are insects, such as ladybugs, distinguished by their special hard wings. Today, this is the animal order with the greatest number of species.)

Another way to determine ancient levels of CO2 is also provided by plants. The latter harness this gas and to assimilate it they have microscopic holes in their leaves known as stomata.

This photograph, taken with a microscope, shows a stoma, one of the many tiny ‘’mouths’’ of leaves of plants that permit them to absorb carbon dioxide.

If the concentration of this substance increases in the atmosphere, plants will need less of these orifices to use it and so their number will decrease. Thus, stomata on fossilized leaves can be counted to gauge the level of CO2 at a given time.

GIGANTIC DINOSAURS BECAUSE OF CO2?
This high level of carbon dioxide also had another effect on vegetation. The latter generally grow better in an atmosphere enriched with this gas because plants use it as discussed above, so one can imagine that herbivorous dinosaurs had a lot of food. According to some scientists, that explains why dinosaurs became so big. To test this assumption, Ginkgos biloba, trees that existed at the time of dinosaurs and have persisted to the present day, were placed in an atmosphere enriched with carbon dioxide and oxygen to re-create an atmosphere similar to that of ancient times. The trees grew up to three times faster than they do in current conditions!

A ginkgo tree in Hiroshima in Japan. In 1945, it grew about 1 km (0.6 mile) from the epicenter of the atomic bomb dropped on this city by the United States. The temple that was originally next to it was blown up by the explosion. A new building was built and its stairs were separated to leave a gap for the trunk. Ginkgos biloba appeared hundreds of millions of years ago. They were found throughout the Mesozoic Era (the age of dinosaurs) in vegetation very different from that found at present. Grass, for instance, did not exist. Yet, after this, they gradually started to disappear as other species of trees evolved. They finally came to be located in a region of China where monks patiently grew them for 1 000 years. This tree is now associated with Buddhism, and one can see it around temples. Some of these plants are as much as 3 000 years old!

Not all scientists share this view. For example, Jorn Harald Hurum, a paleontologist at the University of Oslo in Norway, notes that "All dinosaurs were not big. Moreover, huge animals are known throughout the last 200 million years. Even today, such creatures can be found, including whales, elephants, and giraffes.” Christopher R. Noto, a researcher who specializes in dinosaurs at Stony Brook University in the United States, thinks that "We must take into account different phenomena that can, despite higher levels of CO2, lead to decreases in the plants’ production. For example, there are the questions of soil exhaustion, of greater plant sweating due to an increase in temperature, and of difficulty for plants accessing light because of the others around it. Let us also note that an increase in CO2 can cause plants to have less nutritional content, or even to be no longer edible. This is the case for plants that use CO2 to synthesize elements that serve as defense for the plant," continues this scientist. Dr. Lionel Cavin, curator of the Department of Geology and Paleontology at the Museum of Natural History in Geneva, Switzerland, also sees no direct connection between plants that grow faster and big animals: "Today, the areas with the largest quantities of vegetation are found in the tropical forests. Yet it is not there, but in the savannas, where big animals live." One can imagine that it should have been the same during the dinosaur era, because large animals have difficulty moving between the trees in a forest. As we shall see later, these issues play a role in the reconstruction of Mesozoic climate.

THE DINOSAURS’ CLIMATE

In what ways did the dinosaurs’ world differ from ours? The first difference is that Earth was generally warmer than today because of astronger greenhouse effect, so the distribution of climates was not the same.

This map shows Jurassic climates, a period during the era when dinosaurs lived. Yellow: humid climates in summer; pink: deserts; light pink: humid climates in winter; green: temperate climates; blue: cold climates. Note the absence of ice at the poles.

The continents were configured differently than at present. This is because, at the beginning of the Mesozoic, all continents were joined, forming a single supercontinent called Pangaea, before they gradually separated. “Whereas dinosaurs initially all lived on the same continent, due to its breakup, these animals were separated from each other,” says Dr. Lionel Cavin. ”As they evolved to be better adapted to their specific environment, over time they became more and more typical of a certain geographical area." continues this researcher specialized in the Mesozoic fauna. Christopher Noto stresses that this era lasted a very long time, allowing for major evolution. "The Tyrannosaurus rex was more distant in time from the dinosaur Allosaur than it was from man!”

A Tyrannosaur skeleton. At 13 meters (43 feet) long, 5 meters (16 feet) high, and 7 tons in weight, it is one of the largest carnivores that ever lived on this planet. A less gigantic ‘’version’’, Allosaur, existed before Tyrannosaur.

As far as climatology is concerned, the equator today is generally characterized by a climate with warm temperatures and heavy rainfall throughout the year. "At the time of the dinosaurs, the situation was different, because this region [in yellow on the map] was not humid all the time," explains Christopher Noto, who participated in the writing of the article showing this map.“This resulted from a climatology marked by huge monsoons, but the later did not occur in this region of the globe." The tropics are bordered to the north and the south by deserts (in pink on the map). As one advances toward the poles, seasonally wet climates (in light pink) are again encountered, then temperate climates (in green), and finally cool regions near the poles (in blue). How do we know this?

The first map shows plant diversity in the Jurassic era (the bigger the circle, the greater the number of plant species known at this location, as indicated by fossils). The second lists the places where coal (black circles) and evaporates, a type of rock, (white circles) can be found. The last shows where the dinosaurs were located (a larger circle denotes a greater number of species).

"Coal provides an indication about the climate, since it is formed in wet conditions. Evaporites, a type of rock, occur in environments characterized by strong evaporation, indicating dry climates," says Professor Noto. We notice that animals are not necessarily located where there is the most vegetation. This, as we have seen above, can be explained and is a phenomenon also observable today. Regarding flora, some plant species grow in warm climates, others in wet environments, and so on, so their fossils also provide indications about their environment and are included in the map showing climates. Concerning the distribution of dinosaurs, we can see that it was different from present-day distributions of animals. Whereas today the largest concentration of animal species is in the equatorial region, the latter seems to have been little inhabited during the Jurassic. Terrestrial life was found mostly at middle latitudes, with the highest biodiversity in the northern hemisphere.

A LOST WORLD OF TROPICAL FORESTS?
Christopher Noto calls for caution in interpreting such information. "The fact that fossils are scarce in equatorial regions does not necessarily mean that these regions did not support diverse species. Indeed, even assuming that there was a rainforest, we would not necessarily find traces of it." This is because hot, humid forests are not conducive to fossilization. In such an environment, bones rapidly deteriorate, and plants use the minerals leached from bones for their own metabolism. Furthermore, carcasses are not covered, as happens, for example, in a river, where pieces of rock, transported by water, come to rest over them. Another aspect is that dead animals are eaten by carnivores or scavengers. Small bones are eaten and therefore destroyed. As we saw above, forests are populated by small- to medium-sized animals, which are less likely to be fossilized than bigger ones. In addition, a large bone will be more well preserved than a small one since nature needs more time to degrade it. "It is therefore possible to imagine that a world similar to the current tropical forests existed in the equatorial regions but that no indication of them was preserved," concludes Christopher Noto. Concerning tropical regions, another problem may also be the difficulty with which these areas are accessed, which limits possible fossil discoveries. For example, this is the case for the Sahara, the third largest desert after Antarctica and the Arctic, with an area larger than that of the United States! Michael Arthur Paesler, a physicist at North Carolina State University (the United States), is preparing an expedition to search for fossils in this geographical region . . . with a dirigible. This scientist developed a radar system that makes it possible to detect fossils that will be carried by the aircraft. "As we will have to work in an environment where it is difficult to operate computers, the information collected with the radar will be sent to a satellite. The satellite will transmit the data to the United States, where they will be analyzed," explains Professor Paesler, who is delighted at the idea of the potential discoveries that such an enterprise can bring. Indeed, this place was far from lifeless. We know that episodic but significant rains happened, thanks to the signs that such events have left in the ground. The fossils give us information about the fauna that lived here.

For example, herbivores were generally 6 to 15 meters (20 to 50 feet) long. It is therefore possible to imagine this desert as it was 100 million years ago!

THE SAHARA DESERT, 100 MILLION YEARS AGO

This flying reptile, with a wingspan of about 70 cm (2 feet), is a pterodactyl.

One night a pterodactyl put its long beak on the ground. In the calm of the night, it fell asleep, but suddenly it heard a noise. Moving with the help of its wings, the reptile went to the edge of the mound that served as its refuge. It saw a herd of Ouranosaurus nigeriensis dinosaurs moving around down in the plain.

The Ouranosaur was a desert dinosaur that resembled a camel. After sunset, the crest on its back was used to emit excess heat absorbed during the day. It probably also had a mechanism to cool its brain during the day by circulating blood through vessels passing through its nasal region.

The pterodactyl watched them, motionless, from the top of its rock. At each step the dinosaurs were sinking into the sand. They were walking slowly and with a heavy tread. A baby that had certainly hatched not long before was struggling to keep pace. Everything about the Ouranosaurs suggested tiredness. It had not rained for weeks and it was never possible to know when the next rain would happen. The dinosaurs were looking for a watering hole, but these had gradually gone dry. The flying reptile gazed at the landscape bathed in the moonlight, under a starry sky. Already the first light of dawn was appearing. As soon as the sun began to rise in the sky, the air became hot. Soon the temperature reached 50 °C (122°F). The dinosaurs lay down, orienting themselves facing into the sun to minimize exposure. The pterodactyl spread its wings and jumped up and down to leap into the void. Gathering speed, it soared above the sands and the stones. Soon it could feel the effects of hot air currents rising up from the blazing ground on its wings. Its brain, surprisingly large enough to analyze positions and precise balance necessary for flight, allowed it to move with remarkable agility in the air. Starting to soar in circles, it used these movements of the atmosphere to rise up without flapping its wings. Far from the ground, the heat was more tolerable. Large dark clouds were coming up on the horizon; it would finally rain. In anticipation, the pterodactyl landed and found shelter between some rocks. Soon the wind began to blow the sand while the sky darkened. A sheet of rain moved forward, and lighting, intermittently lighting up the plain, could be seen in the far distance. Then a torrential rain started, creating streams. The pterodactyl dipped its beak in a puddle that reached to its feet, then lifted its head to quench its thirst. A few hours after the storm had died down, flowers emerged from the desert soil as far as the eye could see. The Ouranosaurs walked over this carpet of flowers, feeding from it.At the end of the day, the pterodactyl flew off again. It noticed a particular perfume, that of one of the first flowering plants living on the planet. Feeling the warm air of the evening flowing past its wings, it flew over this boundless arid region, which was lying under the orange colors of the sunset.

THE POLAR DINOSAURS

Polar Dinosaurs

Another geographical area that is interesting by virtue of the climate that reined there as well as the solutions that life found for adapting to them are the Polar Regions. These parts of the globe had environments that no longer have an equivalent on Earth. As we have seen above, the poles were colonized by reptiles. In the southernmost latitudes, although they were less cold than today, temperatures fell below 0 °C (32°F) during part of the year, as shown by traces in strata indicating frozen ground at that time. A question then arises: were the dinosaurs cold-blooded animals like the reptiles living today? "It is difficult to imagine that dinosaurs could have survived at such latitudes if this were the case. In the present cold climates, the only animals that are active, such as birds and mammals, are warm-blooded. Besides, [fossils of] dinosaurs of most groups are found in the polar regions," explains Dr. Thomas Hewitt Rich, curator of vertebrate paleontology at Museum Victoria in Melbourne (Australia). He is also one of the world’s most preeminent polar dinosaur specialists. There are indications that certain dinosaurs were actually active year-round, even though the South Pole was plunged into a polar night for three months of the year. For instance, this is the case with Leaellynosaura, a dinosaur with large eyes and very developed optical lobes in its brain. "Thanks to that, it was probably able to discern even small creatures in the darkness of the polar winter,” continues this paleontologist, co-author of the book Dinosaurs of Darkness.

Leaellynosaura, a 60–90 cm (2–3 foot) dinosaur. It was discovered by Thomas Rich and his wife, paleontologist Patricia Vickers-Rich and named after their daughter Leah.

This is not true, however, for all dinosaurs at these latitudes. For example, at least one dinosaur, Timimus hermani, hibernated!

The 3.5 meter (11.5 foot) Timimus dinosaur was also discovered and named by the Riches.

One reaches this conclusion by observing this dinosaur’s bones. "Growth-arrest lines, which reflect periods during which the animal stopped eating, are visible on them," says Dr. Rich. This is a phenomenon similar to the growth rings in cross-sections of tree trunks, which represent a time when the plant no longer grew in the winter. These patterns are nonexistent in other dinosaurs, such as Leaellynosaura, that were active during cold seasons. Reptiles also lived in the Arctic Polar Circle. For example, Svalbard is an island halfway between Norway and the North Pole swept by the winds of the Arctic Ocean. Jorn Hurum is excavating a sea monster’s skeleton, a 15 meter (50-foot)-long Pliosaur with teeth longer than those of a Tyrannosaur, at this place!

The large animal is a Pliosaur, a sea reptile that lived during the dinosaur era.

This island had already given up other secrets; we know that dinosaurs lived here, since their tracks have been found. Although this region was less northward when the footprints were left, it was part of the Arctic Circle. "There was probably snow in the winter," Professor Hurum speculates.

How is this information relevant to the question of present-day climate change? Besides the fact that the climates of the dinosaur age can show us what a world with more CO2 looks like, they also allow testing the models used by climatologists to predict future climates. In this case, one takes into account the different distribution of the continents, the fact that Earth was not spinning at the same speed—so the dinosaurs’ days were half an hour shorter than ours!—and, of course, the higher atmospheric level of carbon dioxide. Yet the result is . . . not correct.

The first map is the one we saw earlier. The second resulted from using a climate model. The color code for both maps is the same (yellow: humid climate in summer; pink: deserts; light pink: humid climate in winter; green: temperate climate; blue: cold climate).

The model predicts the succession of climates that we saw on the first map. Going from the equator to the poles, one finds a tropical zone that is humid during the summer, deserts, temperate climates, and cold climates. The temperate climates (in green) represented in the equatorial region cannot be confirmed or invalidated, since the conditions existing in these areas are unknown. The most blatant error is that too much area shows up as cold climates (in blue) in the high latitudes in the version generated by the model, particularly in the Southern Hemisphere. The problem is that the model’s prediction of heat transfer is too low between the low latitudes and the poles; thus it calculates temperatures that are too cold, for instance, for areas where giant herbivores lived. This could be because the model does not take vegetation into account. Climatologists use this information to improve their models, and more accurate predictions of future climates will most likely be provided.

“CLIMATE CHANGE COULD CAUSE A NEW EXTINCTION”
Beyond the climate change issue, another question is the repercussions of a major increase in the level of carbon dioxide for animal life. As we previously saw, life evolved for 40 million years on this planet in an atmosphere enriched with CO2. Animals adapted to a distribution of climates very different from ours, as we saw in the examples of Ouranosaurus, Leaellynosaurus, and Timimus dinosaurs. Can we thus deduce that life and a lot of CO2 can also coexist in the future? According to Lionel Cavin, "Warmer climates are a normal situation for our planet.” As for Jorn Hurum, he considers that many animals appeared during past global warming events but that these were not the cause of mass extinctions. "These occur in the case of a cooling event. Of course, this does not correspond to the message that one generally hears today,” points out this fossil hunter. Lionel Cavin also believes a correlation exists between temperature and biodiversity: “For instance, we observe in past eras that the warmer the oceans, the higher the fish biodiversity.” Jorn Hurum concludes that the problem essentially concerns humans, since they live in areas that will be flooded if the polar ice melts. For his part, Lionel Cavin stresses the importance of the question of transition from one climate to another: "In the case of a shift to a climate 5 °C [about 9°F] warmer than present, this would not pose any long-term problems. On the other hand, the stage of moving from one equilibrium climate to another could be dangerous.” Thomas Rich shares this point of view by explaining that this change could be disastrous because animals adapted to conditions characterized by an important greenhouse effect are not those that currently exist. "Rapid variations cause problems for living organisms," he adds. Christopher Noto adheres to this idea: "CO2 concentration changes have already occurred in the past, but during much longer periods than what we see today.” According to this scientist, animals evolved, adapted, or disappeared during these events. When they happen in too short a period of time, fauna can’t change. "This leads to widespread extinctions," he adds.

                                                                      Gaëtan Dübler