Climate change and the warmer temperatures it is bringing means that heat-related mortality will increase in most regions of the world. In the most likely climate change scenarios, that increase will not be compensated globally by a reduction in cold-related deaths.
Heat Waves are already a problem in many cities around the world, killing people in both temperate and hotter regions, and with climate change this is only set to get worse.
“There is little evidence that humans will be able to acclimatise quickly enough to the rising temperatures, and if they can’t, then we will see a considerably higher mortality from heat waves due to climate change,” senior advisor at UNEP DTU, Gerardo Sanchez Martinez, predicts.
Twice the amount of days with heat waves by 2045
As part of the work on Climate Resilient Development UNEP DTU is working to mainstream climate change adaptation into heat wave prevention plans in urban settings.
Collaborative research led by UNEP DTU and the WHO Regional Office for Europe has focused on Antwerp, in Belgium, as a case study.
The results showed an increase in mortality at temperatures above 26 degrees Celsius. From 2009-2013, an average of 13 people died each year due to a yearly average of 16 “hot days” with temperatures reaching and exceeding that limit.
Using the most recent climate models the number of days, where mortality increases due to heat, will more than double in Antwerp by 2045.
UNEP DTU analysis on heat waves in cities is designed to feed directly in to policy making on prevention plans. A key point in this work is that today’s prevention is not enough for tomorrow’s heat waves.
“We are preparing for the heat waves we have now, without taking into account how future heat waves and the people they affect are going to be. When talking about heat waves, we need to take climate change and population dynamics into account, “Gerardo Sanchez Martinez explains.
He emphasises the importance of basing heat wave prevention plans on empirical data, like the temperature at which mortality starts to increase. If a plan is activated too late people will have already died and if it is done too soon, that would harm credibility and waste resources.
Heat and pollution create the perfect storm in cities
Heat waves and heat in general are already problems in both cities and rural areas. With the climate getting warmer, this will only become a more persistent issue. An issue that will claim more and more lives worldwide. Especially in cities the predicted increase in heat waves, both in number and severity, will increase risk for people’s health.
This is due to the fact that materials usually found in cities, such as asphalt, concrete and stone absorbs heat more and release it less than vegetation. Cities get warmer than rural areas.
Added to this is the higher levels of air pollution in cities. People with respiratory or cardiovascular problems are particularly vulnerable to both air pollution and excess heat.
“It is a very harmful combination for people with certain pre-existing conditions. The synergetic effect of air pollution and heat is like the perfect storm,” Gerardo Sanchez Martinez says.
At the same time, there is a higher concentration of vulnerable people in cities. This includes elderly people, pregnant women and small children besides people with pre-existing conditions such as respiratory or cardiovascular diseases. All are groups who are more likely to become ill or die during extreme heat.
An approach that can be easily copied
Looking at health and temperature data, to see at what temperature mortality increases, and combining this with models on how the climate will develop in the near future, the cities will know when to activate heat wave prevention plans, and when they should start revising this threshold.
Gerardo Sanchez Martinez stresses that this approach easily can be transferred to other settings. Rising temperature is a global issue, and low income countries are even more vulnerable to the adverse effects, such as the predicted increase in heat related mortality.