Accelerated increase in heatwave duration as global warming continues: Study – OXBIG NEWS NETWORK-OxBig News Network

A new study has projected that for every fractional increase in global warming, the duration of heatwaves could extend by a greater amount than previously observed. This suggests that as the planet continues to warm, heatwaves will last longer at an accelerating rate.

The longest heatwaves will see the greatest acceleration in extending in duration, and the frequency of the most extreme heat waves will increase the most, the study found.

Climate change has been consistently linked to hotter, longer, more intense and frequent heatwaves. However, the study, published in the journal Nature Geoscience, found a “non-linear” increase in heatwave duration concerning an increase in warming by a fraction of a degree.

“Each fraction of a degree of warming will have more impact than the last,” said senior author David Neelin, professor of atmospheric and oceanic sciences at the University of California Los Angeles, US. “The acceleration means that if the rate of warming stays the same, the rate of our adaptation has to happen quicker and quicker, especially for the most extreme heat waves, which are changing the fastest,” Neelin said.

The research team from the US and Chile analysed historical and projected temperatures using publicly available climate models and those from the European Centre for Medium-Range Weather Forecasts.

The authors wrote, “Each increment of regional time-averaged warming increases the characteristic duration scale of long heatwaves more than the previous increment.” “We (also) found that the longest and rarest heatwaves in each region — those lasting for weeks — are the ones that show the greatest increases in frequency,” lead author Cristian Martinez-Villalobos, assistant professor of engineering and science at the Adolfo Ibanez University, Chile, said.

Tropical regions are expected to see larger changes compared to temperate regions, and heatwaves during summer to prolong more, compared to warm spells during winter.

“If you have large variations in current climate, then a fraction of a degree change will have less impact than if you have a more stable climate,” Neelin noted.

“So, impacts in tropical regions tend to be bigger than in temperate regions, and winter warm spells will change less than summer because summer tends to have smaller variability,” the senior author stated.

The team has also developed an equation which is flexible to analyse heatwaves in a region or help gain broader insights across multiple regions, they said.

“By taking into account the natural variation of temperatures at each location, we find that recent observed trends of heat wave durations already follow a similar pattern of acceleration predicted by climate models,” Martinez-Villalobos said.