Palpable global warming for 96% of humans: study

Whether they realize it or not, some 7.6 billion people – 96% of humanity – have felt the impact of global warming on temperatures over the past 12 months, researchers have said.

But some regions felt it much more strongly and frequently than others, according to a report based on peer-reviewed methods from Climate Central, a climate science think tank.

People in tropical regions and small islands surrounded by heat-absorbing oceans have been disproportionately affected by human-induced temperature increases to which they have barely contributed.

Of the 1,021 cities analyzed between September 2021 and October 2022, the capitals of Samoa and Palau in the South Pacific had the most discernible climate footprints, the researchers said in the report released Thursday.

Temperature spikes in these locations were typically four to five times more likely to occur than in a hypothetical world in which global warming had never occurred.

Lagos, Mexico City and Singapore were among the major cities most at risk, with human-induced heat increasing health risks for millions of people.

Climate Central researchers, led by Chief Scientist Ben Strauss, have been looking for a way to close the gap between global warming on a planetary scale – usually expressed as Earth’s average surface temperature over a period of earlier reference – and people’s daily lives. live.

“Diagnosing climate fingerprints lets people know that their experiences are symptoms of climate change,” Strauss told AFP. “It represents a signal and shows that we have to adapt.”

Using seven decades of high-resolution daily temperature data from the European Center for Medium-Range Weather Forecasts (ECMWF) and two dozen climate models, Strauss and his team created a tool: the Climate Change Index.

The tool calculates the probability that abnormally hot weather at a specific location on a given day is due to climate change.

In 26 cities, for example, at least 250 of the 365 days from October 2021 saw temperature increases that were at least three times more likely to be due to climate change.

– ‘Unfair and tragic’ –

Most of these cities were in East Africa, Mexico, Brazil, small island states and the Malay Archipelago – a chain of some 25,000 islands belonging to Indonesia and the Philippines.

“The warming effect is much more noticeable in the equatorial belt because there has historically been less temperature variability there,” Strauss told AFP.

This is why even a relatively modest increase in local temperatures caused by global warming fits so clearly into the index, he explained.

“Island temperatures are strongly shaped by the temperature of the ocean around them,” said Strauss, who has also mapped the projected impacts of sea level rise on coastal areas around the world.

“To see that small island states have already lost their historic climates – even as they risk losing their land to rising seas – seems very unfair and tragic.”

The urgent need for money to help vulnerable tropical nations adapt to climate impacts will be squarely on the table when nearly 200 countries gather in 10 days for the UN climate talks in Egypt.

Rich countries have yet to deliver on a decade-old promise to increase climate finance for developing countries to $100 billion a year, even though the UN’s climate advisory panel, the IPCC, estimates that the annual costs of adaptation could reach a trillion dollars by 2050 if warming continues at a rapid pace.

The map-based climate change index tool can be found here: https://csi.climatecentral.org/csi-contour-map/tavg/2022-10-27/

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Teresa H. Sadler