Royal Society report warns of extreme weather risk

Are extreme weather events increasing as a result of climate change and what impacts will they have on our environment? Can human intervention via engineering solutions effectively mitigate the impacts of extreme weather, or should we rely on the natural ability of ecosystems to endure extreme events?

As we enter an era of climatic uncertainty, such questions will be of increasing relevance to scientists and policy-makers alike. In the latest Ecological Issues publication – ‘The Impact of Extreme Events on Freshwater Ecosystems’ – the BES assessed the threat posed by extreme weather events and examined the evidence for different approaches by which we might better predict their impact and develop policy to increase society’s resilience.

The topic of extreme weather events was revisited in a report published today by the Royal Society – ‘Resilience to Extreme Weather’. Focusing on flooding, drought and heatwaves, the report combines the impact of climate and demographic changes to provide global maps that illustrates how society’s exposure to extreme events will change between the present day and 2090.

Estimated changes in flood frequency for the period 2080–2099 relative to the period 1986–2005.
Estimated changes in flood frequency for the period 2080–2099 relative to the period 1986–2005.

One of the key objectives of the report was to highlight that the most extreme changes in weather will occur where people live. Based on the assumption of a population of nine billion by 2090 and a temperature increase of 2.6-4.8°C – the current trajectory of emissions – the report estimates that by the middle of the century large coastal cities alone could face combined annual losses of $1tn as a result of flooding. The Royal Society also warns of the vulnerability of an ageing population to heatwaves.

The authors stated that their analysis suggests that a portfolio of defensive options would best address the range of weather extremes. In particular, they encourage those who invest in infrastructure to look beyond traditional engineering options and incorporate ecosystem-based approaches, as there is evidence to suggest they are more affordable and deliver wider societal benefits while simultaneously reducing the immediate impact of the hazard.

Estimated changes in drought intensity for the period 2080–2099 relative to the period 1986–2005.
Estimated changes in drought intensity.

The authors also want reform of the financial system such that action to reduce exposure to extreme weather is incentivised. They have called for organisations to report their maximum probable losses due to extreme events, based on a 1% chance of the event on any given year. The importance of goods and services provided by the natural environment to the business and finance sector was a key focus of discussion at the Natural Capital Initiative’s Valuing our Life Support Systems 2014 event.

Further recommendations raised by the report’s authors included a call for government to incorporate resilience-building into policy, an increase in the availability of international funds for measures that build resilience to extreme weather, and greater coordination between governments at the international level to build resilience and share expertise when tackling common risks.

With the latest Intergovernmental Panel on Climate Change (IPCC) report making an “unequivocal” case that “climate change will increase the likelihood of severe, pervasive and irreversible impacts for people and ecosystems”, this report by the Royal Society adds to the increasingly large evidence-base urging governments to take immediate action to address climate change impacts.

On the risk facing people by weather extremes, the report’s lead author, former BES President Professor Georgina Mace said “this problem is not just about to come… it’s here already.”