A Nobel Prize for climate modellers a sign of the times

Before I became a science journalist, initially focusing on climate and environmental topics, I spent seven years working as a climate physicist. So it was with delight that I read of the Nobel Prize for Physics being awarded this week to a pair of climate modellers.

Climate physicists Syukuro Manabe, at Princeton University, and Klaus Hasselmann, at the Max Planck Institute for Meteorology, shared the prize with theoretical physicist, Giorgio Parisi, for his contribution to theories of complex systems. This is the first time that the award has been granted to physicists working in the area of climate.

Climate modellers work on building and using models of the Earth’s climate to simulate and predict the world of the future. Their work today can be traced back to the early pioneering ideas of yesterday’s awardees.

In the 1960s, Manabe’s research showed how carbon dioxide impacts the temperature of the planet, and that the temperature rises in response to increased carbon emissions. In the following decade Hasselmann built the first conceptual model to describe the Earth’s climate, using the mathematics which govern the physics of the weather and climate systems.

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I remain absolutely fascinated to this day about how these simulations of the planet can be used to predict the climates of the past, present, and future. My PhD work, for example, involved using climate models to simulate the world of the last Ice Age (20,000 years ago), with a particular focus on the behaviour of the oceans at that time.

The Earth’s future climate is predicted by running the climate models for the present day, making sure they accurately simulate the world of today, and then moving them forward in time while increasing carbon dioxide levels. Climate modellers use different scenarios, based on how much carbon dioxide we expect in the atmosphere, to get a feel for how our future world will look in, say, 2050 or 2100.

The models I used – and which most modellers adopt today – are called Earth System Models, because they simulate all the important components of our planet’s climate system, including the atmosphere, oceans, cryosphere (ice-sheets and sea ice) and the land vegetation systems, which include everything from grasslands to forest and tundra. Together, the innovation behind these highly complex models represents something of a spectacular art, drawing in some of the greatest ideas from the world of physics.

Whenever you hear a prediction for the future climate, or how we have to limit our carbon output to achieve a 2 degree global warming – rather than a detrimental 4 degree warming, for example – this is the work of climate modellers and their sophisticated models. These are now invaluable tools which governments regularly use for help in determining national policy around decarbonisation programmes which aim to achieve an established limit to global heating.

Without these tools it would be impossible, not only to make predictions for Earth’s future, but also to have a conversation around the issues at hand, and negotiate and formalise international agreements for global decarbonisation.

It is an important point, and sign of the times, that we are now seeing the first Nobel prize awarded to pioneers in the climate space, and we can be sure it won’t be the last. No doubt some of the prizes of the future will be awarded to the physicists who help create the new sustainable energy systems which will ultimately help to avert climate catastrophe.

Dr Conor Purcell writes on science and its role in society and culture. He has a PhD in Earth Science and is the 2021 European Meteorological Society’s Journalist of the Year