Science has long predicted climate change. Economics has been slow to respond. Indeed, as economist Steve Keen has said about economists and climate policy, ‘if economists hadn’t interfered, we would be twenty years further along’.
The scientific prediction that rising concentrations of climate-relevant trace gases such as CO2 and methane in the atmosphere will make the Earth warmer was made as early as 1859 by the Irish physicist John Tyndall. He had discovered that carbon dioxide absorbs infrared heat radiation. In 1895, Svante Arrhenius, who later won the Nobel Prize for Chemistry, calculated a linear relationship: If the proportion of CO2 in the atmosphere doubles, the average global temperature will rise by two to six degrees Celsius.
In the 1970s, this prediction became relevant with the increasing emission of CO2, and the US National Academy of Sciences was the first major research association to warn of this man-made greenhouse effect and put the effect of a doubling of CO2 at +1.5 to +4.5 °C. This report went down in the history of climate research as the “Charney Report”, named after the chairman of a group of scientists who were already working on the first models for the connection between CO2 and the climate. The report was entitled Carbon Dioxide and Climate: A Scientific Assessment, and it predicted global temperature changes with astonishing accuracy forty years later.
What do current climate models tell us about the causes of climate change? The correlation is now as good as 100% clear to climate researchers: Models that take into account the measured increase in CO2 concentration in the atmosphere reproduce the developments of the climate in the last decades very well, and the correlation between CO2 emission and temperature increase is highly significant. If, on the other hand, they use models in which the CO2 concentration is missing, explanatory power drops sharply.
So, global surface temperatures are indeed rising with almost 100% probability (in science, there is never 100% certainty) due to the gases we emit into the atmosphere. The corresponding climate models fit the globally measured data too well to reject this, as climate sceptics do again and again with alleged alternative reasons – all of which have already been scientifically investigated and refuted.
Which leads to an important question: Is the relationship between the concentration of atmospheric greenhouse gases and the average global temperature linear as measured in recent decades? Can we, therefore, rely on the fact that with a (soon to be achieved) doubling of the CO2 content in the atmosphere, the temperature will “only” increase by about 1.5 to 4.5 °C?
The answer is clearly ‘No.’ Due to various feedback effects, most climate models today assume a non-linear correlation at higher CO2levels, which means a much stronger temperature increase with further CO2 increases.
That is because of feedback effects, whose occurrence means that instead of running linearly through the system, they return to the system, so that their effects are not linear but quadratic or even cubic. In addition, the climate-relevant forces can also build up abruptly. In this case, significantly higher average temperatures on Earth would be expected. Let’s consider two examples of such non-linear relationships:
First, with the global temperature increase, the water vapor content in the atmosphere increases. Methane gases frozen in the Arctic and in the north of Russia are released. In both cases, the climate changing greenhouse effect increased significantly. Accordingly, temperatures rise suddenly and much faster than linearly.
Second, the oceans also play an important role in the global CO2-cycle. Currently, more than half of the CO2 produced annually by humans is stored in the ocean for a long time. However, the higher the temperature of the seawater, the less CO2 dissolves in it. The associated release of CO2 from the oceans causes a non-linear amplification of the greenhouse effect and thus further warming. So, it may be that the predicted global warming of a few degrees Celsius lulls us into a false sense of security if the world’s oceans suddenly react differently than before with respect to their CO2 absorption.
An example of how climate researchers are repeatedly surprised by the dramatic nature of events can be seen in a new development in climate research. Until now, it has been assumed that local weather data produced too much “noise” to discover a clear fingerprint of climate change in such micro-cases. That is why it makes little sense to say, in the face of a particularly hot spring day, “That’s climate change!” Equally, the cold snap in Utah in 2019, for example, when -37 °C was measured on an October day, is also no argument that climate change does not exist.
However, at the beginning of 2020, climate researchers from ETH Zurich proved in a sensational publication that climate change is now clearly recognizable in daily weather data from all over the world. To do this, they formed values for the global weather from countless local weather data – the global weather sum, so to speak, and this for every day of the last few years. They were astonished to find that these weather totals directly showed global warming for every single day: Compared with the global weather totals from the period 1951 to 1980, every day since spring 2012 had been too hot on our planet with 97.5 percent confidence. It is not individual local weather extremes that constitute climate change. However, if you look at global weather data, there has not been a single day since 2012 when the entire world’s weather has been unaffected by global warming.
In short, climate scientists have been warning about climate change for 60 years. Yet, for 60 years, they have been largely ignored. Why have governments underestimated such an important development as climate changes for decades?
Besides the strong influence of oil companies (in the US), there is another reason worth mentioning. According to Australian economist, Steve Keen politicians take their advice mainly from economists.
Yet do we know of any physicists or even weather experts as key advisors to politicians? There are hundreds of thousands of excellent articles by climate scientists. But if you look at who governments cite in their own work on climate change, two-thirds are articles by economists, of whom there are no more than a few hundred publications, and less than one-third are articles by natural scientists.
But where economists think they deliver research worth Nobel Prizes, Keen sees ridiculous assumptions that have allowed governments to justify doing nothing about climate change. Thus, according to Keen, economists are part of the problem in the climate crisis.
Steve Keen’s book Debunking Economics is a compelling exposition of why neoclassical economic theory is not only wrong but more of a threat to the survival of capitalism than any number of left-wing revolutionaries. He was one of the handful of economists to realize that a serious economic crisis was imminent and to publicly warn of it from as early as December 2005.
According to the famous climate scientist and activist James Hansen, we should treat climate change like an approaching meteorite, not as the neo-classics of economics say, like an approaching holiday in the Mediterranean. By overly discounting the future, underestimating feedback loops, and overlooking negative externalities, the consensus of economic advice on climate change is not up to the task. While we might not go as far as to paraphrase Shakespeare (‘first, let’s kill the economists’), it is long past the time that policymakers should pay more attention to economists than scientists when it comes to climate change.