Climate change is reshaping the conditions on which human civilisation depends. From rising mortality risks to modelling challenges, the actuarial profession must urgently engage with this evolving threat.
Climate change is undoubtedly one of, if not the, gravest threats facing humanity. We are already seeing signs of increasingly frequent extreme events linked to changes in weather patterns, which themselves are attributable to changes in the climate driven by human activity.
These include droughts, floods, wildfires and more frequent, powerful storms, including hurricanes and typhoons, the latter of which are driven by the increasing amount of heat energy in our atmosphere.
In and of itself, this would not present an insurmountable problem. But the key issue is that significant changes are manifesting over a relatively short timeframe, making it hard to adapt fast enough to avoid serious repercussions.
It is not too much to say that our civilisation is currently almost entirely reliant on regular, moderate, and predictable weather patterns. These support the availability of key resources that we need to survive, including fresh water and food. Modern agriculture itself is dependent on stable climatic conditions.
There are other relationships between climate-impacted variables and mortality, including the direct effects of temperature, with extreme hot and cold both associated with increased mortality.
The spread of diseases is another key factor to consider. Respiratory diseases tend to spread more widely under colder conditions, when people spend more time indoors in close proximity. Higher temperatures support the spread of vector borne diseases such as Lyme disease, West Nile virus and malaria – and perhaps even other tropical diseases – to parts of the world where they are unknown.
There is also the prospect of economic turbulence and indeed direct weather-related damage that could disrupt the provision of vital services, including healthcare.
With such obvious linkages to the field of mortality, it is perhaps surprising that there has been somewhat less focus on climate change within the mortality and longevity community.
One likely reason is that from a modelling point of view – as Paul Sweeting reminded us in his Presidential Address – climate change is a hard problem to tackle, given the lack of historical precedent for the changes we are seeing (and might reasonably expect to see in coming decades). It also relies on vast amounts of data and is compounded both by the complexity of the systems involved and the corresponding need for judgement in setting assumptions.
Part of the challenge is also related to the fact that we are still exploring and trying to understand what the ‘correct’ levels of important variables might be, including how sensitive the climate is to increasing greenhouse gas emissions and their corresponding temperature changes.
Nonetheless, there is considerable output available from the scientific community on modelling a variety of future climate scenarios. The investment and general (P&C) insurance sectors have already been making use of these to try and understand potential future losses and design risk management approaches accordingly.
Another likely factor in the relatively low level of climate engagement to date is the high levels of uncertainty, and the long time horizons involved. Many different future paths can be equally justified based on the data currently available. Some are relatively benign, while others forecast catastrophic outcomes even before the end of this century.
But based on current information, it is not unreasonable to conclude that the point at which a worsening climate will lead to materially increasing mortality rates is most likely still 20 years or more into the future. Indeed, according to research presented in a joint report published by the IFoA and University of Exeter, we might expect to see 50% GDP destruction due to negative climate impacts by around 2070 to 2090, depending on how models are calibrated. (See: Planetary Solvency – finding our balance with nature)
However, these timescales are now well within range of the projections typically made by longevity actuaries, especially those considering deferred annuities (where policyholders may still be 10 or more years from their retirement date, and with a further 25 years of life expectancy or more beyond that point). It is increasingly critical and certainly past time for actuaries to investigate this important topic properly.
The October 2025 edition of the IFoA’s Longevity Bulletin, with climate change its theme, is now available. It has an excellent range of articles covering several approaches to help fill the gaps in our understanding about how climate change may affect mortality in the decades to come.
It is increasingly incumbent not only on those working in the field of mortality modelling, but on actuaries everywhere to engage more strongly with this issue and help our pensions and insurance industries navigate these increasingly choppy waters.
