Carbon dioxide, public enemy No1?

The 1997 Kyoto Protocol and the 2009 Copenhagen Summit identified carbon dioxide emissions and their effects on global climate as the main environmental threat to be tackled by modern societies, and environmental activists, such as Greenpeace, also put most of their energy into defeating the same beast. However, from a geologist’s perspective, this could be seen as an interesting paradox. In fact, carbon dioxide stands out as the “good guy” in the geological record, and problems show up when there is not enough of it in the atmosphere; not the contrary.

It is generally assumed that the current trend of global warming is detrimental to humanity and ecosystems in general. However, the geological record clearly indicates that the global ecosystem thrives during greenhouse ages and declines during ice ages, such as the one that we are presently experiencing. These observations on the long-term geological record are never part of the debate on global warming, which is usually constrained to the last few hundred years, or thousands of years at best.

Clearly, this does not bring enough perspective, as we have to go back 35 million years to get out of the current ice age, which started with the birth of an ice sheet on Antarctica. Since then, ecosystems have been experiencing tremendous stress due to the gradual deterioration of global climate. The current trend of global warming is but a small notch in a large scale trend of global cooling that started more than 100 million years ago. Prior to then, in Early Cretaceous times, the carbon dioxide levels of the atmosphere were more than six times higher than those of today, allowing life to flourish more than it ever had since the early Paleozoic (i.e., since the previous greenhouse age).

The current long-term cooling trend is caused by several orogenic events, which increase calcium and magnesium inputs to the oceans, from the erosion of continental crust, and which therefore promote the long-term storage of carbon in carbonate rocks (CaCO3 and CaMg(CO3)2). Most of these orogenic events are still ongoing (Himalayas, Alps, Rockies, Andes, etc.), and the current ice age is therefore destined to keep aggravating … unless we release a sufficient amount of the atmospheric carbon that is presently locked in fossil fuels …

Discrepancies between the geological record and global warming models

Most predictions on the effects of global warming are fatalistic. It seems to be the general consensus that ecosystems will suffer, although geological history states the contrary. Models also predict an increase in desertification, although greenhouse ages, such as that of the Cretaceous, seem to be devoid of deserts, which are features of ice ages.

One recurrent theme in alarmist global warming models is the prediction that there will be an increase in tropical storms. Again, the geological record suggests otherwise. For one thing, it is wrong to believe that CO2-induced global warming will result in a temperature increase for all regions of the globe. The absence of desert conditions during greenhouse ages suggests that profound changes occur in sub-tropical latitudes due to CO2-induced global warming, which may in fact result in substantial cooling for this specific latitudinal range.

Due to the dynamics of the Hadley cells, moisture is currently conveyed from sub-tropical (10° to 30°) to equatorial latitudes (0° to 10°), which explains why the former is mainly characterised by deserts while the latter hosts rain forest. Due to this, sub-tropical latitudes are currently much warmer than equatorial latitudes due to the greater cloud cover in the latter region, which allows less solar radiation to reach the ground. Somehow (perhaps due to the establishment of a less steep vertical gradient in temperature, which would effectively change the dynamics of Hadley cells), moisture and heat become better distributed during greenhouse ages and sub-tropical deserts cease to exist.

It is very likely that tropical storms would subside as well, as they are also the products of excessive heat in the dry, sub-tropical latitudes, whereas equatorial areas are devoid of them. The equatorial region is in effect a “shelter from the storm”, as suggested by a recent compilation by the National Oceanic and Atmospheric Administration (2005). In other words, although alarmist research on global warming pictures a greenhouse Earth as Dante’s Hell, the geological record rather presents it as a worldwide Garden of Eden, with no temperature extremes.

There is also reasonable grounds to doubt the predictions for an imminent (or even ongoing) substantial decrease in the volume of polar ice sheets, because the latter began to form when carbon dioxide levels were substantially higher than today (35 and 7 million years ago for Antarctica and Greenland, respectively), and because of their self-sustaining nature, due to their high albedo (reflectance). The geological record clearly indicates that ice-sheets can survive under a climate that is substantially warmer than the one in which they started to form. Human-induced global warming is presently far from bringing the climate to temperatures that would substantially exceed those of seven million years ago, and it is unlikely that it ever will.

Alarming footage of melting glacier fronts are in fact not alarming at all, as glacier fronts are always experiencing melting, even as they advance. Only the central portions of an ice-sheet are under conditions that allow the accumulation of snow and ice (accumulation zone), whereas its marginal portions are under a climate in which melting exceeds accumulation (ablation zone). Ice flows plastically from the accumulation zone to the ablation zone in response to gravity, but it does not form in the latter zone.

More alarming than the fact that climate models are not supported by the deep geological record is the fact that climate modelers are generally not aware of these discrepancies. There are no efforts being put forward to explain why human-induced increases in atmospheric carbon dioxide would stimulate desertification, whereas naturally induced increases did the contrary in the past, simply because climate modelers are generally not aware that previous greenhouse ages were devoid of deserts.

Because five-day weather predictions are still quite unreliable, although they can be tested every five days, 100-year climate predictions are hardly convincing. Testing them every 100 years is not very useful, and the geological record is therefore the only available ground on which to test them. However, this is clearly not being done, simply because climate modelers do not have a geological background, and because geologists have not been properly included in the debate on climate change.

Why it may be crucial to stop looking at carbon dioxide as public enemy #1

Carbon dioxide is not a pollutant. It is, in fact, the “greenest” gas in our atmosphere, and the most essential ingredient for life itself. It has no odour, no colour and no ill effects whatsoever. All it does is nourish life and keep our climate warm. It is the primary and most essential nutrient at the very base of the food chain, as photosynthetic plants, algae and bacteria remove it from the atmosphere and hydrosphere to store it in their tissues. Along with water vapour, it keeps our planet away from the temperature extremes experienced daily by planetary bodies that are devoid of it, such as our own moon.

It is somewhat disconcerting that the rise of carbon dioxide levels has been somehow established as the greatest environmental threat faced by humanity, even though the pros and cons of this rise have never been properly assessed. Most scientific assessments on the issue of global warming only bring into focus its negative aspects and are therefore biased. As a result of this biased propaganda, which portrays carbon dioxide as the main evil of modern times, it is now considered by most as a blasphemy to dare bring forward any data that happen to place the accused in a good light.

It is well-known and non-controversial that the biosphere was in much better shape during the Cretaceous, when carbon dioxide levels were several times higher than today. Of course, whenever there is a change in external conditions, there are winners and losers. If crop species are doing better, chances are that pest species are not doing so well, and vice-versa. During the Cretaceous greenhouse age, benthic (bottom-dwelling) species were the main losers, as the oceans became permanently stratified, bringing anaerobic conditions on the deep seafloor. However, the hardships of benthic fauna, a minute fraction of the world’s biomass and biodiversity, were largely outdone by sheer happiness in the pelagic (water-column-dwelling) and terrestrial realms.

Most agree that, whether or not it is true that the current rise in atmospheric CO2 is detrimental, “better be safe than sorry” and work at curbing down emissions. Not necessarily. It all depends on what method is used to curb down emissions. For instance, many environmentalists are turning to alternative fuels, like used kitchen oils, to lower their contribution to global warming. It is sad to say that such environmentally-responsible people may in fact pollute more than less concerned citizens. However, if you remove carbon dioxide from the equation, they certainly do. Most of these alternative fuels do not burn nearly as well as refined gasoline. As a result, they emit much greater amounts of particulates, volatile organic compounds and carbon monoxide, which are “true” pollutants.

If everyone switched to these alternative fuels, cities would soon become unlivable due to a quick rise in these atmospheric pollutants. In contrast, carbon dioxide is “not” a pollutant. While so much international effort is put forward to deal with the “carbon dioxide case”, less notorious environmental threats get a chance to stay out of the spotlight and thrive on the diversion (when did you last hear about acid rain?).

Another reason why we should give carbon dioxide a fair trial and a chance to revoke itself as public enemy #1 is the fact that it is a very strong opponent to tackle. The economic drawbacks of the ongoing climate war are astronomic, especially for developing countries. The widespread switch to “biofuel” farming is also creating a food crisis.

Moreover, before putting in place enormous international efforts such as the Kyoto Protocol and the Copenhagen Accord, it would have been preferable to derive proper estimates on which prospect is to be most feared, global warming or global cooling? Ice sheets have been intermittently covering most of North America and northern Europe over the past 2.5 million years. Just as winter and summer, glacial advances and retreats are clocked with orbital cycles. The “summer solstice” of this interglacial cycle (warm eccentricity peak in the Milankovitch cycles) is already 5,000 years behind us, and we are now heading towards the next winter. The current human-induced rise in atmospheric CO2 may be slowing down global cooling, but it is very unlikely that temperatures in the “Milankovitch winter” (we are now in the “Milankovitch autumn”) will ever exceed those of the “Milankovitch summer”. Hence, with the parallel threat of orbitally-induced global cooling, a more sophisticated and less biased assessment of climate evolution and its consequences for the global ecosystem is needed to better guide intervention strategies.

Looking at the geological record, it becomes quite obvious that the overall global cooling that the Earth is experiencing is a more important concern for the health of ecosystems than the temporary trend of global warming that we are presently observing.

Ironically, the only way to prevent the next glacial advance, which would be far more catastrophic for humanity than the so-called threat of global warming, is to keep sending back carbon dioxide to the atmosphere by releasing some of its excessive storage in the crust. Unfortunately, the release of carbon from carbonate rocks is energy consuming, but there very well might be enough accessible fossil fuels in the upper crust to give us the means to avoid suffering the next glacial advance.

In other words, there might come a time when humanity will try to find ways to burn more fossil fuels in order to save the day. By then, the 1997 Kyoto Protocol and the 2009 Copenhagen Summit might be seen as one of history’s greatest parodies.