June 24, 2024

What’s Making This Year So Damn Hot? : ScienceAlert

Man-made climate change is outpacing natural weather phenomena to drive scorching heat waves in Asia, Europe and North America that could make 2023 the hottest year on record, say scientists.

Here experts explain how 2023 got so hot, warning that record temperatures will get worse even if humanity sharply cuts its emissions of planet-warming gases.

El Nino and more

After a record hot summer in 2022, this year the Pacific warming phenomenon known as El Nino is back, warming the oceans.

“This may have provided additional warmth to the North Atlantic, but as the El Nino event has only just begun, it is likely only a small part of the effect,” Robert Rohde of the US temperature monitoring group Berkeley Earth . write in the analysis.

The group calculated that it was 81 percent 2023 may be the warmest year since thermometer records began in the mid-19th century.

Dust and sulphur

Atlantic warming may also have been exacerbated by a reduction in two substances that normally reflect sunlight from the ocean: dust blowing from the Sahara desert and sulfur aerosols from shipping fuel.

Rohde’s analysis Temperatures in the North Atlantic region have seen “very low levels of dust coming from the Sahara in recent months.”

This was due to unusually weak Atlantic trade winds, said Karsten Haustein German Federal Center for Climate Service.

Meanwhile, new shipping restrictions in 2020 reduced toxic sulfur emissions. “This would not explain the entire North Atlantic spike at the moment, but it may have contributed to its intensity,” Rohde noted.

‘stagnant’ anticyclone

Warming oceans affect the land’s weather patterns, triggering heat waves and droughts in some places and storms in others. The warmer atmosphere sits up moisture and dumps it elsewhere, said Richard Allanprofessor of climate science at the University of Reading.

The scientists drew attention to the length and intensity of the long anti-cyclonic systems that bring the heat waves.

“Where stagnant high pressure areas stand over continents, the air floods and warms, melting away the clouds, creating an intense summer sun that pares the soils, heating the ground and air above,” with heat waves “put in force” for weeks, Allan said.

In Europe, “the warm air pushing in from Africa is now waiting, and high pressure conditions have set in which means that the heat in the warm sea, on land and in the air continues to build,” Added by Hannah Clokeclimate scientist at the University of Reading.

The role of climate change

Scientists at the Intergovernmental Panel on Climate Change (IPCC) they said in their global summary report this year that deadly heat waves have become “more frequent and more intense across most land regions since the 1950s” due to climate change.

This month’s heat waves are not a single phenomenon but several actors at the same time,” said Robert Vautard, director of France’s Pierre-Simon Laplace climate institute. “But they are all exacerbated by one factor: climate change.”

Higher global temperatures make heat waves longer and more intense. Despite being the main driver, climate change is one variable that humans can influence by reducing emissions from fossil fuels.

​”We ​​are moving out of the well-known normal natural oscillations of the climate into unfriendly and more extreme territory,” said Melissa Lazenbysenior lecturer in climate change at the University of Sussex.

“However, we have the potential to reduce our human impact on climate and weather and not create more extreme and longer heat waves.”

Heat forecast

Berkeley Earth has warned that the current El Nino could make the Earth even warmer in 2024.

The IPCC has said there is a risk that heat waves will become more frequent and more intense, although governments can limit climate change by reducing countries’ greenhouse gas emissions.

“This is just the beginning,” said Simon Lewischair of global change science at University College London.

“Deep, rapid and lasting cuts in carbon emissions to net zero can halt warming, but humanity will have to adapt to even more intense heat waves in the future.”

© Agence France-Presse

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