Man-made climate change is supercharging natural weather events to bring scorching heatwaves across Asia, Europe and North America that could make 2023 the hottest year on record. records, say scientists.
Here experts explain how warming will occur in 2023, warning that these record temperatures will worsen even if humans drastically cut emissions of the gases that warm the planet.
El Nino and others
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, although since the El Nino event has only just begun, this is likely only a small part of the effect,” Robert Rohde of the US temperature monitoring group Berkeley Earth wrote in a analysis.
The group estimates that there is an 81-percent chance that 2023 will be the warmest year since thermometer records began in the mid-19th century.
Dust and sulfur
The warming of the Atlantic may also be exacerbated by the reduction of two substances that normally reflect sunlight from the oceans: the dust that blows in the Sahara desert and the sulfur aerosol from the shipping of fuel.
Rohde’s analysis of temperatures in the North Atlantic region noted “unusually low levels of dust coming from the Sahara in recent months.”
This is due to unusually weak Atlantic trade winds, said Karsten Haustein of Germany’s federal Climate Service Center.
Meanwhile new shipping restrictions in 2020 lower toxic sulfur emissions. “This does not explain all of the current spike in the North Atlantic, but may have increased its severity,” Rohde said.
Warming oceans affect weather patterns on land, triggering heat waves and droughts in some areas and hurricanes in others. A warmer atmosphere will absorb moisture and dump it elsewhere, said Richard Allan, professor of climate science at the University of Reading.
Scientists highlight the length and intensity of ongoing anticyclone systems that bring heatwaves.
“Where stagnant high-pressure areas persist over the continents, air sinks and warms, melting clouds, causing intense summer sunlight to warm the earth, warming the land and air in above,” with heatwaves that have “set the area” for weeks, Allan said.
In Europe, “the warm air pushing in from Africa remains in place today, with high pressure conditions which mean that the heat of the warm sea, land and air continues to build,” added Hannah Cloke, a climate scientist at the University of Reading.
The role of climate change
Scientists at the Intergovernmental Panel on Climate Change (IPCC) said in their global summary report this year that climate change is making deadly heat waves “more frequent and more severe in most regions of the earth since 1950s”.
This month’s heatwaves are “not one event but several movements at the same time,” said Robert Vautard, director of France’s Pierre-Simon Laplace climate institute. “But they are all reinforced by one factor: climate change.”
Higher global temperatures make heat waves longer and more severe. Despite being the primary driver, climate change is a variable that humans can influence by reducing emissions from fossil fuels.
“We have moved from the usual and well-known natural oscillations of the climate into unchartered and more extreme territory,” said Melissa Lazenby, senior lecturer in climate change at the University of Sussex.
“However, we have the ability to reduce our human influence on climate and weather and not create more severe and lasting heatwaves.”
Berkeley Earth warns the current El Nino will warm the Earth by 2024.
The IPCC says heatwaves risk becoming more frequent and severe, even if governments can limit climate change by reducing countries’ greenhouse gas emissions.
“This is just the beginning,” said Simon Lewis, chair of global change science at University College London.
“Deep, rapid and sustained cuts in carbon emissions to net zero will halt warming, but humanity will have to adapt to more severe heatwaves in the future.”
© 2023 AFP
Citation: What makes 2023 likely to be the hottest year on record (2023, July 18) retrieved 18 July 2023 from https://phys.org/news/2023-07-hottest-year.html
This document is subject to copyright. Except for any fair dealing for the purpose of private study or research, no part may be reproduced without written permission. Content is provided for informational purposes only.