Increasing global warming from currently one to two degrees Celsius by the middle of the century could expose around 25 percent more people to the risk of tropical cyclones, a new study has shown. However, emission reductions that would limit global warming to 1.5 degrees Celsius could cumulatively protect over 1.8 billion people from tropical cyclones by the end of this century, it said.
Hurricanes and typhoons are already among the most destructive natural disasters in the world and potentially threaten around 150 million people every year. In addition to climate change, population growth is causing further exposure to tropical cyclones, particularly in the coastal areas of East African countries and the United States.
“If we add the population growth to two degrees Celsius of global warming, we could even see an increase of around 40 percent more people exposed to cyclones in 2050,” says a researcher from the Potsdam Institute for Climate Impact Research (PIK) and the German Weather Service (DWD), Tobias Geiger.
“As the world population is expected to peak by the middle of the century, more people will face more powerful cyclones due to climate change – putting that larger population at greater risk,” said Geiger, who is also the lead author of the new study published in ‘Nature Climate Change ‘says a press release.
The global ambition is to limit the warming to well below two degrees Celsius, but compared to unchecked climate change even global warming of two degrees Celsius 50 years later could lead to a completely different result, as an interdisciplinary team of scientists from Germany, Switzerland and the USA found in a computer-aided analysis: By 2100, population models predict a casual, regularly decreasing population in cyclone-prone areas on a global level.
“This would partially compensate for the additional burden of warming, as Geiger emphasized:” If we reduce greenhouse gas emissions quickly and only reach two degrees Celsius of global warming in 2100, this will likely increase the number of people at risk from hurricanes to 20 percent. This finding is critical as it shows that reducing global warming may postpone severe tropical cyclone impacts to the late second half of the century, when much fewer people were at risk.
Timing is key in assessing cyclone exposure
In the study, the scientists analyzed the combined effects of demographics and climate change on people exposed to tropical cyclones – and found that timing of reaching certain levels of warming is crucial. At the state level, the results are even clearer, said Johannes Gutschow.
â€œOur model shows with unprecedented level of detail that in 2050 all countries with a high risk of tropical cyclones are projected to increase exposure. Based on the projected population growth, we found exposure changes of almost 300 percent in some East African countries, up to 100 percent in the US, and also a sharp increase for the Arabian Peninsula. “
This picture changes with less rapid warming scenarios. Johannes Gutschow added: â€œBasically, our computer model can calculate the impact of any given global and country warming scenario and its impact on the number of people at risk from tropical cyclones. Our results most likely also apply to a multitude of other climate extremes, the occurrence of which depends only on absolute warming and not on time. “
The co-head of the PIK research department on transformation pathways, Katja Frieler, emphasized: â€œIn accordance with the NDCs, the number of people at risk of hurricanes would continue to rise over the course of the century, for example in the hurricane-prone regions of the USA. “
â€œEmission reductions that would limit global warming to 1.5 degrees Celsius could cumulatively protect over 1.8 billion people from tropical cyclones by the end of this century, compared to the warming under the currently proposed emission reductions. It is therefore high time to reduce greenhouse gases quickly. “Emissions in order to protect as many people as possible,” the press release said.