Professor Stevens used the occasion of his talk in the BBVA Foundation to give a preview of the ideas contained in the paper appearing that same Monday in Proceedings of the National Academy of Sciences (PNAS). In this article titled  “The scientific challenge of understanding and estimating climate change,” co-written with Tim Palmer, a research professor in the Department of Physics at the University of Oxford, the authors take stock of what science has achieved so far, and the much that remains to be done to understand and deal with the challenge of global warming.

“The reality is that there are a lot of things we still don’t know,” admitted Stevens at the start of his talk, while cautioning the audience not to “get confused,” since “we already know enough to be sure that it is prudent to act now in order not to make the problem worse.”

The Director of the Max Planck Institute for Meteorology explained that climate change science has established certain key facts beyond any shadow of a doubt. “We now know, thanks largely to the immense contributions of scientists distinguished with the Frontiers of Knowledge Awards in Climate Change, that greenhouse gases are accumulating in the atmosphere as a result of human activity, and that these gases are the main drivers of the rise in global temperature.” Starting from this solid scientific bedrock, the international community, he argued, must take urgent steps to curb emissions of these pollutant gases.

“There is no question that we are causing profound changes in the Earth’s climate, and the consequences of global warming are tangible,” Stevens insists. “The only sensible thing, then, is to do all we can to ease the problem.”

But is this truly what we are doing? Stevens went on to describe our current climate models as “very imprecise” when it comes to predicting impacts at the regional level – for instance, how much rainfall may increase in tropical zones – and this makes it harder to plan preventive measures to safeguard the communities that could be affected.

“There is still a lot of uncertainty about how the climate will react to rising temperatures,” he warned, “because the models we have are simply inadequate.”

The urgent need for “more reliable models”

It is due to the deficient reliability of the tools available to climate researchers that Stevens stresses the urgency of developing far more accurate models, based on supercomputing, that improve our ability to predict climate behavior in a context of global warming.

“Today’s most advanced computing techniques allow us to perform simulations of climate behavior with much greater precision,” Stevens said. However, in view of the seriousness of the situation, a major international and multidisciplinary effort will be needed, comparable to the past feats of the scientific community in response to such daunting challenges as the moon landings, with the Apollo project, the exploration of the origins of the universe through the construction of large telescopes, or the elementary structure of matter, through the construction of powerful particle accelerators.

“The big problems, such as climate change, call for great scientific ambition, involving the construction of large facilities driven by human innovation. We have to respond as a society to major challenges, and that is why we need a ‘CERN’ for climate change.”

From this point of view, Professor Stevens concluded that the need to advance in this field of research is more important than ever, because “we know the risk is large enough to demand solutions,” but at the same time we need “better tools” that let us deal with the challenge before it is too late.