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Take it to the limit

Simon Sharpe and Emily Shuckburgh argue that climate research should focus on ultimate risks

For more than 30 years, researchers have warned of the dangers posed by climate change and pointed to the solutions. Meanwhile, global emissions have continued to rise, with governments’ targets implying that in 2030 they will be equivalent to around 20 gigatonnes of carbon dioxide per year above those consistent with limiting warming to 1.5C.

Researchers might feel they have done all they can. The three academics who in 2021 called for a moratorium on climate change research until governments acted with the requisite urgency may be outliers, but many are likely to sympathise with this view.

This is a dangerous misperception. Climate change research has more to do. A new focus, aligned more closely with political and social interests, could yet change the speed and strength of action.

Dangerous thresholds

To act decisively on climate change, governments need to understand the scale of the risks. Risk assessment starts by asking: ‘What is the worst that could happen?’ It then considers how likely that is.

Most climate science does the opposite, asking what is most likely and how that might affect society. This leaves governments knowing less than they should about dangerous thresholds that could be crossed.

For example, the worst that could happen to a coastal city is that sea levels rise beyond its capacity to adapt. Such estimates are rare, but for London, one study suggests this would be a global sea level rise of five metres.

One of us worked on climate change in the UK government for 10 years without meeting a minister or senior official who knew of this finding. Yet a 2021 assessment from the Intergovernmental Panel on Climate Change suggests that, while deep uncertainties remain, it is conceivable that the five metre threshold could be hit within the next 150 years.

Another example is the threshold of heat and humidity that exceeds the body’s tolerance for heat stress, meaning that even a healthy person resting in the shade would die.

A recent study suggests that warming of only 2.5C might leave tens of millions of people on the wrong side of this threshold. This presents extreme danger to many societies yet is much less well known and researched than incremental changes in heat-related mortality and labour productivity.

Informing policy

There will be many such thresholds—from the biophysical, such as the maximum temperature at which a crop can survive, to the socioeconomic, such as the minimum freshwater supply required to meet human needs. The Intergovernmental Panel on Climate Change’s latest report warns that there is still “little detailed information” on how such limits relate to different levels of environmental change.

In other words, many opportunities remain to provide the kind of information most important for understanding the scale of the risks.

The opportunity for research into solutions to climate change is, in some ways, a mirror image. Governments need to know the best that could happen so that they can aim to achieve it.

There are likely to be many thresholds whose crossing enables rapid, non-linear, structural change in decarbonising the global economy, just as there were in past industrial revolutions. But at present, much of the economics used to inform policy assumes a state of equilibrium, in which nobody has any reason to change. Not surprisingly, the greatest successes in low-carbon transitions have stemmed from disregarding advice based on such assumptions.

Research into disequilibrium economics tends to appear in science journals, as the leading economics journals fail to recognise it as economics. When university funding formulae reward publication in top economics journals, this locks in a system that is not giving governments the information they need.

Risks and solutions

Researchers and funders have the power to change both climate science and economics. To make the risks clear for governments, pursue research that asks first what the worst that could happen is and then works to understand its likelihood. To give better advice on the solutions, focus on understanding the economy as a complex dynamic system.

Academic research cannot, on its own, be expected to move governments to respond proportionately to the threat of climate change. Activism, leadership and every kind of innovation will be needed too. But research should aim to be as effective as possible.

With the political consensus on climate change under strain, a clear view of the risks, along with advice on how to focus resources on points of maximum leverage, is more vital than ever. It is not a moratorium on climate research that is needed, but a transition.

Simon Sharpe is the author of Five Times Faster: Rethinking the Science, Economics and Diplomacy of Climate Change, and Emily Shuckburgh is director of Cambridge Zero.

A version of this article also appeared in Research Fortnight