The world is rapidly reaching a climate tipping point, where millions of people will be forced to leave their habitual environments due to unprecedented temperatures and extreme weather events. A recent study predicts that by 2030, 2 billion people will experience average annual temperatures above 29C, a level that most communities have never faced before. The consequences of inaction will be catastrophic, with urgent action to lower carbon emissions and keep global temperature rise to 1.5C offering a glimmer of hope.
The study, which has treated every citizen equally, unlike previous economic assessments of the damage of the climate crisis, has revealed that up to 1 billion people could choose to migrate to cooler places. However, those areas remaining within the climate niche would still experience more frequent heatwaves and droughts. India and Nigeria face the worst changes, with India already suffering from extreme heatwaves and a recent study finding that more than a third of heat-related deaths in summer between 1991-2018 occurred as a direct result of human-caused global heating.
The researchers have identified the climate conditions in which human societies have thrived, defining the climate niche as areas with mean annual temperatures between 13C and 25C. Outside this range, populations face higher death rates, lower food production, and lower economic growth. The study’s lead author, Prof Tim Lenton, noted that the costs of global warming are often expressed in financial terms but the study highlights the phenomenal human cost of failing to tackle the climate emergency.
Humanity’s Comfort Zone Faces Disintegration in Global WarmingThe researchers used climate and population models to examine likely future changes in the number of people outside the climate niche, defined as above an annual average temperature of 29C. The results are alarming, with each rise of 0.1C in global temperature above the 1.2C of human-caused global heating already seen driving an extra 140 million people outside the niche. If global temperature continues to rise towards 2.7C, the heating combined with a growing global population will mean 2 billion people living outside the niche by 2030 and 3.7 billion by 2090.
In contrast, rapid and deep cuts to emissions to keep heating to 1.5C would hugely reduce the number of people outside the niche, with 90 million people in India living with an average temperature above 29C, compared with 600 million if global temperature rose to 2.7C. The study’s findings emphasize the huge inequality of the climate emergency, with those people with low emissions suffering the greatest changes in extreme heat exposure.
The most practical and immediate option to adapt to high temperatures is to increase green spaces in cities, which can shave 5C off extreme temperatures and provide shade. The study’s results have led to a clearer understanding of the direct human suffering that climate change could cause, with Dr Richard Klein noting that living outside the niche means suffering due to an unbearably hot and possibly humid climate. Another expert, Dr Laurence Wainwright, said that humans have got used to living in particular areas at certain temperatures, and when things change, serious problems arise, whether in terms of physical health, mental health, crime, and social unrest.