Why are mathematical models for predicting climate change lagging behind technological advances?by Adam Levy / March 5, 2014 / Leave a comment
“Computer scientists, mathematicians and physicists are challenging the assumptions climate models are traditionally based upon” © Dolovis WM Commons
Niels Bohr’s famous line that “prediction is very difficult, especially about the future” rings true for climate change. To help us understand how manmade emissions affect our planet, climate scientists have developed some of the most sophisticated computer models ever created. These models allow us to evaluate hypotheticals such as what our climate would be like if the industrial revolution hadn’t happened and no greenhouse gases were emitted. They can also be used to make projections for future change, allowing us to estimate how hot it will get in our lifetimes and further into the future. Perhaps most importantly, they allow us to unpick how climate change will affect different regions of the world, enabling us to better understand the human impacts of climate change, and adapt where possible.
Yet climate models—like all models—are imperfect. Today, progress in improving these models seems to be slowing down, even as computer power multiplies exponentially. Climate models are released in “generations,” about once every six years, which coincide with each IPCC (Intergovernmental Panel on Climate Change) assessment report, allowing each report to take advantage of the most up to date simulations. The previous generation of models was released for the 2007 IPCC report, and was able to capture present day climate approximately 30 per cent more accurately than its predecessor. The state-of-the-art models—developed for last year’s report—only improved on their predecessor by a further 20 per cent. Yet in the six years between the latest two generations there was a 60-fold increase in computer power.
Why, then, are improvements in climate models lagging behind technological advances? To understand, we first need to understand how climate models work, and why they are flawed. Climate models operate by simulating the relevant physical processes, such as thermodynamics and fluid flow, across the globe. These models allow us to explore how climate will be affected by various scenarios—from “business as usual” scenarios where the world continues to emit more and more CO2, to extreme mitigation scenarios where emissions start to fall rapidly within the next few years.
These models take years to develop and require powerful supercomputers to run. These computers certainly earn their name: the Met Office supercomputer in Exeter cost £30m and fills a…