As per a study conducted by the London School of Hygiene and Tropical Medicine (LSHTM) and the University of Bern within the Multi-Country Multi-City (MCC) Collaborative Research Network, 37% of heat-related deaths worldwide between 1998-2018 were caused by human-induced global warming.
The research derived the actual contribution of man-made climate change in increasing mortality risks due to heat by collecting data from 732 locations in 43 countries worldwide. However, the lack of empirical data from larger parts of Africa and South Asia had limited the study from including locations from all world regions.
The article published in Nature Climate Change shows that the highest percentage of the number of deaths due to Global warming was in Central and South America (up to 76% in Ecuador or Colombia) and South-East Asia (between 48% to 61%).
"We expect the proportion of heat-related deaths to continue to grow if we don't do something about climate change or adapt. So far, the average global temperature has only increased by about 1°C, which is a fraction of what we could face if emissions continue to grow unchecked," Dr Ana M Vicedo-Cabrera, from the University of Bern and the first author of the study said.
The authors consider their findings as further evidence for the necessity to adopt strong mitigation policies to reduce warming in the future, and to implement interventions to protect populations from the adverse consequence of heat exposure.
However, future climate conditions foresee a substantial surge in average temperature with extreme events such as heat waves that would add to the danger.
The research practised a 'detection & attribution' study that identifies and attributes observed phenomena to changes in climate and weather. The team analysed past weather conditions simulated under scenarios with and without anthropogenic emissions. This enabled the researchers to classify the warming and related health impact linked with human activities from natural trends.
Several factors such as the local change in climate and vulnerability of its population determine the climate-related heat casualties ranging from a few dozen to several hundred deaths each year per city. However, the most affected are the populations living in low and middle-income countries who contributed less to anthropogenic emission in the past.
"This is the largest detection & attribution study on current health risks of climate change. The message is clear: climate change will not just have devastating impacts in the future, but every continent is already experiencing the dire consequences of human activities on our planet. We must act now," Professor Antonio Gasparrini from LSHTM, senior author of the study and coordinator of the MCC Network, said.
In the UK, 82 deaths in London, 16 deaths in Manchester, 20 in West Midlands and 4 in Bristol and Liverpool every summer contribute to 35% of deaths due to global warming.