Is there any evidence that the CO2 affects the heat on Earth?

Answer

Dear Jean

Since 1900, the average temperature of the Earth’s surface has risen by about 1 degree. At the same time, the concentration of CO₂ in the atmosphere increased by almost 50% (from 280 to 410 ppm). These are the facts. Those who deny these facts are in the camp of the flat-earth supporters, the young-earth creationists (who claim that the earth is exactly 6022 years old) and the man-on-the-moon deniers. In short, they belong to the group of people who throw overboard all science that does not fit in their ideological alley. They conveniently forget that they too benefit fully from the prosperity that the same science has brought to society, such as, for example, exploiting the rich energy sources in our subsurface.

Someone with scientific training could now rightly suggest that a simultaneous increase in CO₂ and temperature does not mean that the former is the cause of the latter (correlation ≠ causality). Maybe it’s just a coincidence or there’s some other factor at play that we don’t know yet. Of course, scientists have already been intensively working on these questions. However, based on a series of theoretical, experimental and empirical arguments*, one can only conclude that the increase in the amount of CO₂ (and methane, CH₄) in the atmosphere actually plays a very dominant role in global warming. After an intensive debate of at least 40(!) years, there is now a broad scientific consensus, just as there is a broad consensus about (the main features of) the theory of evolution, the rotation of the earth around the sun, and the relationship between earthquakes and plate tectonics. However, that does not mean that we fully understand all the complexities of the processes. Certainly not.

Other comprehensive scientific theories have also reached a stage of broad consensus only after long discussions and despite strong resistance. Yet the devil is in the details, and those details lead to further investigation and discussion. Creationists like to use such uncertainties and disagreements in the scientific community to undermine evolution as a whole. ‘Climate deniers’ do exactly the same thing: “this observation can be used with the CO₂ model of the warming cannot be explained, so that model is not correct”. Of course, that’s not how science works. A scientific theory is built piece by piece, tested with new data, adjusted and improved. No single comprehensive theory is able to explain all related observations. Sometimes a generally accepted theory is rejected if a competing model better explains the observations. Striking in the climate debate: the ‘climate skeptics’ (including relatively few climate scientists) seldom if ever come up with a well-founded alternative explanation model for the observed phenomena. Many ‘climate skeptics’ therefore prefer to simply deny the facts and thus fall into the category of the aforementioned flat-earth supporters.

As soon as the politicians all accept that the science has long been established that the current, geologically extremely rapid, global warming is largely caused by our CO₂ emissions, it is finally possible to take measures to reduce CO₂ implement reduction.

*For a clear and concise overview of the arguments for the role of CO₂ in the climate I refer to a recent article in de Volkskrant.