A new Comment led by Professor Paul Behrens brings together experts in climate, nature, health, national security and financial risk to call for a more integrated approach to how governments assess and prepare for climate and nature threats.
Writing in Nature Climate Change, the experts warn that economic modelling and national security assessments can give policymakers very different pictures of the severity of the same climate and nature risks. Without a common framework for bringing those assessments together, governments can be left with conflicting advice about how seriously to act and how much to spend.
The research comes after a summer provisionally recorded as the UK's hottest, ending with almost three-quarters of England in drought. July was England's driest July since at least 1836, contributing to water restrictions affecting around 30 million people, more than 1,100 wildfires and reduced yields for some crops.
National security assessments typically consider reasonable-worst-case scenarios, while economic modelling tends to focus on central estimates and cost-benefit calculations. Both can inform decisions on public spending, adaptation, food and security.
The contrast can be seen in recent UK assessments. A national security assessment published in January concluded with high confidence that global ecosystem degradation and collapse threaten UK security and prosperity. Meanwhile, economic modelling used to inform UK fiscal policy expresses climate damage in projected economic losses, while acknowledging that some potentially severe risks remain difficult to quantify.
“Climate risks don't happen in isolation. This summer's extreme heat and drought affected farms and food production, put pressure on water supplies and ecosystems, and had consequences for people's health.
Professor Paul Behrens, British Academy Global Professor at the Oxford Martin School and lead author, said: “Climate risks don't happen in isolation. This summer's extreme heat and drought affected farms and food production, put pressure on water supplies and ecosystems, and had consequences for people's health. Those impacts can ripple out into food prices, infrastructure and the wider economy. Looking at each risk separately can seriously underestimate the overall impact.”
The authors argue that where potential damage is severe and irreversible, being under-prepared can cost far more than preparing for an event that ultimately proves less damaging.
Lieutenant General (retd) Richard Nugee, of the University of Oxford's Climate Change and (In)Security Project, said a more consistent approach to assessing risk is already used in military planning: “In the military, a well thought through, coherent framework is used to identify all the factors involved and derive the best, or least-worst, course of action. Given the gravity of the consequences, it is imperative to have a consistent and comprehensive approach that does not underestimate the challenge.”
The authors propose bringing expert analysis alongside model estimates to account for serious risks that are difficult to quantify. They also want climate, nature, food, health, economic and security risks brought into a shared framework, so risks identified in one area are not overlooked elsewhere.
“Restoring nature is part of preparing for climate risk. Reconnecting rivers to their floodplains, rewetting peatlands and restoring wetlands can slow and store water, reducing flood peaks downstream while helping landscapes hold water through drought and giving wildlife room to recover.”
Their approach also identifies "no-regret" actions that bring benefits even if the worst-case scenario never happens. These include measures such as improving energy efficiency and restoring ecosystems.
Highlighting the role that nature itself can play in building resilience, Nathalie Seddon, Professor of Biodiversity at the University of Oxford, said: “Restoring nature is part of preparing for climate risk. Reconnecting rivers to their floodplains, rewetting peatlands and restoring wetlands can slow and store water, reducing flood peaks downstream while helping landscapes hold water through drought and giving wildlife room to recover.”
Governments already use reasonable-worst-case approaches to prepare for some severe risks, including pandemics. The authors call for these changes to be made before an equivalent climate or nature shock exposes where governments were under-prepared.