No, I do not intend to present some other “sweeping” Climategate-like “proofs” that all those climate scientists warning since the 1960’s that human activities influence the global climate have been wrong. Quite the contrary, to date, science tells us clearly that the Earth is warming and that we are those responsible. Moreover, it tells us that it is likely to keep warming unless we do something about it, and if we do not, the consequences may be very unpleasant. So, the title question is entirely hypothetical. Nevertheless, I still find it very interesting because climate science may be wrong.
At least since Karl Popper we know that science does not provide “last answers” or “final proofs” in the literal sense of these terms. Every scientific theory, no matter how widely acknowledged and uncontroversial, may someday be unable to explain a new observation. The theory is then falsified. It can potentially be “immunized” or reformulated so as to accommodate the new observation in some way. But, and this is important to stress, every scientific theory can be falsified (indeed, this is the indispensable condition a theory has to fulfil to be called scientific – it has to be falsifiable). Not only the theory behind anthropogenic climate change, but also quantum mechanics, evolutionary biology, the Big Bang theory or any other theoretical model that deserves the name “science”.
What would be a possible falsification of the “climate change theory”? The obvious case would be if the Earth’s atmosphere would cease warming over a longer period of time (say, 50 years; shorter periods like the slowed warming of the 2000’s and 2010’s are mostly explainable by some countering phenomena, e.g., Sun activity, heat uptake by the deep oceans, the ENSO variation, anthropogenic and natural aerosols etc.) despite continued greenhouse gas emissions. Or if we would stop emitting greenhouse gases, but the Earth would continue warming over a really long period (due to climate system inertia, warming for some decades after an emissions stop is guaranteed). So, what then?
The answer to the question “What if we are wrong about global warming?” is partly dependent on what is the reality then. If the world is to continue warming no matter what we do, the answer should be different from that given in the case of the current warming being just “natural variability” of the climate (though the term “natural” is somewhat problematic here due to the unprecedented pace of the warming until now). In the former case, we would have wasted resources in mitigation efforts, cutting down fossil fuel use more quickly than public health-related reasons alone would justify. On the other hand, resources invested in adaptation would not be wasted at all. In the latter case, the degree of waste would be higher, since no particularly large investments in adaptation would be justified. Given our state of knowledge and the climate denialists’ arguments, however, the latter case could be assumed, somewhat arbitrary though, to be more probable. So, if we are wrong about global warming, we are wasting large amounts of resources, although by far not as much as we should if global warming is anthropogenic. Conversely, it would also mean, in the “natural variability” case at least, that many human lives and livelihoods would be saved compared to the “climate change is real” scenario. This is certainly a point “in favour” of being wrong after all.
This was, however, only one side of the coin. What is its other side? I would argue that the psychological effects of being wrong in this case could be dire. First of all, the credibility of science as such would be undermined deeply. In the end, scientists have been telling us for some 30-40 years that there is anthropogenic climate change, and since the beginning of the 90’s virtually everyone knows that. Most people trust the science in this regard. But if those scientists have been wrong – why should others be right? Especially if they say something we do not like to hear. Widespread science denialism and dismissal would be a typical human reaction in such a case. Which leads us to another problem. As shown impressively in the book Merchants of Doubt by Naomi Oreskes and Erik Conway, there is a huge lobby behind climate change denialists. Those people, who were also engaged in campaigns against pesticide restrictions, the science of second-hand smoking and others, are not concerned with science. They do not care about who is right and who is wrong. What they care about are economic interests. And those people, centred around a few US-American conservative think tanks, would gain a lot if we were wrong about global warming. I do not want to insinuate that all denialists or, as they mostly call themselves, sceptics are “bad”. I firmly believe that many of them just listen to the wrong people and let mislead themselves about climate science. But there are “bad” people among those denying the reality of anthropogenic global warming, and climate science’s “failure” would be their great success. And that would be a defeat to almost anybody else.
Furthermore, the reality of climate change is one of the main drivers of the sustainability movement, also leading “ordinary” people to the gradual acquisition of what may be called sustainable lifestyles. While climate change is actually only one among many reasons speaking in favour of sustainable behaviour, even not necessarily the most important one, it has certainly been the most convincing so far. Our being wrong about global warming could lead many people to the conclusion that not only global warming, but also sustainability is a “hoax”. In the long run, that could become disastrous.
If we are wrong about global warming, humanity is likely to gain (or, actually, not to lose). No climate change would mean no additional deaths from drought-induced starvation, massive floods, extreme weather events and so on. On the other hand, this would also mean that we have wasted some resources. But, as I suggested above, cutting down on fossil fuels has a lot of co-benefits, so it would not be such a big loss as, say, cutting down a rainforest in the belief that this could “save the world”. What concerns me, however, is the potential loss of credibility science and the sustainability movement would experience, and the gain in influence of the vested interests behind all the Fred Singers, Lord Moncktons, Richard Lindzens and Fred Seitzs of this world. On the balance, all the lives not-lost in the case of our being wrong would likely overweight these downsides. But, unfortunately, there is no rational reason to believe that we are wrong.