From the temperatures that do not increase to the ice that does not melt, from the innocence of human actions to the excessive costs of reducing emissions. The list, as we shall see, is long.
Some criticisms have been detailed, others generic. Some have disappeared soon, others have lasted for years, perhaps after turning into something different and only apparently resembling the original dispute. Still others mix baseless hypotheses with shreds of sharable observations. In short, it is not always easy to grasp the sense of criticism and frame it in a historical and scientific context.
It can help make order, try to situate every objection within the theory that links the emissions of some gases to climatic variations and consequent damage to humanity and ecosystems. Explaining in detail the scientific knowledge on climate change would require a lot of space. Since this is not the end of the book, we will limit ourselves to schematizing the scientific evidence on the subject in a couple of steps, without using numbers and without claims of completeness. In reality the theory of climate change is more complex, there are other implications, secondary roads, connections; moreover, the degree of certainty is not the same between the various steps. For now let’s leave out these aspects, they wouldn’t add much if the aim is to provide the background on which to place the negationist objections.
* Greenhouse gas emissions and their accumulation in the atmosphere. Human activities emit large quantities of carbon dioxide and other greenhouse gases. Anthropogenic emissions are able to unbalance the natural cycles of these gases; the result is their accumulation in the atmosphere.
* Increased concentration of greenhouse gases already registered. The increase in concentrations of greenhouse gases in the atmosphere over the last 150 years is of anthropogenic origin. The levels reached by greenhouse gases, in particular CO2, are the highest in hundreds of thousands of years, since man exists on Earth.
* Bond increase in greenhouse gases – temperature increase. An increase in the levels of greenhouse gases in the atmosphere generates an increase in the average temperature of the planet. Directly or due to „feedback“ (for example, the increase in water vapor resulting from a temperature increase). The temperature variation is not homogeneously distributed on the planet, but the final result is an increase in the average temperature of the surface layers of the atmosphere and the oceans. High increases in greenhouse gases in the atmosphere will lead to substantial increases in temperature.
* Temperature increase already registered. The average temperature of the surface of the planet has increased abnormally in recent decades. This temperature increase is the highest in thousands of years. An important part of this temperature increase is man-made.
A study conducted by the Cnr together with the University of Stockholm, published in Nature Communication, estimates that at the end of 2100, the release of greenhouse gases by permafrost could reach a quarter of all emissions linked to the use of fossil fuels: “ A 25% more ‚free‘ – the researchers stress – without satisfying a real energy requirement ”. However, a surplus that has not yet been counted in the estimates for cutting emissions could therefore be insufficient.
A time bomb ready to burst, an ever deeper crack in Pandora’s box of the earth’s climate? Still these are estimates that do not have the chrism of certainty, the research must continue: „The great intrinsic uncertainties are linked to the limits of our knowledge of the Arctic system – explains Tommaso Tesi dell’Ismar-Cnr – for this reason the forecast models of the „The latest IPCC report (the intergovernmental group on climate change, ed) has not yet included it among the various climate feedbacks.“
“Karakorum, mountain range between Pakistan, India and China„