UCI researchers: Climate change will alter the position of the Earth’s tropical rain belt

From UC Irvine

Difference by the year 2100 expected to impact global biodiversity, food security

January 18, 2021UCI researchers: Climate change will alter the position of the Earth’s tropical rain beltRoughly in line with the equator, Earth’s tropical rain belt is expected to shift irregularly in large hemispheric zones as a result of future climate change, according to a new study by UCI civil & environmental engineering and Earth systems science researchers. The alterations are expected to cause droughts and threaten biodiversity and food security across broad swaths of the planet by the year 2100. NASA

Irvine, Calif., Jan. 18, 2021 — Future climate change will cause a regionally uneven shifting of the tropical rain belt – a narrow band of heavy precipitation near the equator – according to researchers at the University of California, Irvine and other institutions. This development may threaten food security for billions of people.

In a study published today in Nature Climate Change, the interdisciplinary team of environmental engineers, Earth system scientists and data science experts stressed that not all parts of the tropics will be affected equally. For instance, the rain belt will move north in parts of the Eastern Hemisphere but will move south in areas in the Western Hemisphere.

According to the study, a northward shift of the tropical rain belt over the eastern Africa and the Indian Ocean will result in future increases of drought stress in southeastern Africa and Madagascar, in addition to intensified flooding in southern India. A southward creeping of the rain belt over the eastern Pacific Ocean and Atlantic Ocean will cause greater drought stress in Central America.

“Our work shows that climate change will cause the position of Earth’s tropical rain belt to move in opposite directions in two longitudinal sectors that cover almost two thirds of the globe, a process that will have cascading effects on water availability and food production around the world,” said lead author Antonios Mamalakis, who recently received a Ph.D. in civil & environmental engineering in the Henry Samueli School of Engineering at UCI and is currently a postdoctoral fellow in the Department of Atmospheric Science at Colorado State University.

The team made the assessment by examining computer simulations from 27 state-of-the-art climate models and measuring the tropical rain belt’s response to a future scenario in which greenhouse gas emissions continue to rise through the end of the current century.

Mamalakis said the sweeping shift detected in his work was disguised in previous modelling studies that provided a global average of the influence of climate change on the tropical rain belt. Only by isolating the response in the Eastern and Western Hemisphere zones was his team able to highlight the drastic alterations to come over future decades.

Co-author James Randerson, UCI’s Ralph J. & Carol M. Cicerone Chair in Earth System Science, explained that climate change causes the atmosphere to heat up by different amounts over Asia and the North Atlantic Ocean.

“In Asia, projected reductions in aerosol emissions, glacier melting in the Himalayas and loss of snow cover in northern areas brought on by climate change will cause the atmosphere to heat up faster than in other regions,” he said. “We know that the rain belt shifts toward this heating, and that its northward movement in the Eastern Hemisphere is consistent with these expected impacts of climate change.”

He added that the weakening of the Gulf Stream current and deep-water formation in the North Atlantic is likely to have the opposite effect, causing a southward shift in the tropical rain belt across the Western Hemisphere.

Full article here.

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Coach Springer
January 19, 2021 6:25 am

So their models are built on hard, detailed and comprehensive observations of how many position changes of “Earth’s Tropical Rainbelt”?

Brian Bellefeuille
January 19, 2021 9:21 am

“Mamalakis said the sweeping shift detected in his work was disguised in previous modelling studies that provided a global average of the influence of climate change on the tropical rain belt. Only by isolating the response in the Eastern and Western Hemisphere zones was his team able to highlight the drastic alterations to come over future decades.”

If I read this correctly, the “..drastic alterations..” were disguised as “..global average..” in the original SOTA models. If this hidden gem is such a major climate changer, doesn’t that call the original models into question?

Richard Patton
January 19, 2021 9:51 am

The biggest problem that their models have is the ignoring of the laws of physics. Because of the trade winds, caused by Coriolis force, which in turn is governed by the laws of motion, the tropics will always be between 10°N and 10°S. It bugs the heck out of me when writers (any writers, scientific or otherwise) ignore the laws of physics to get their weather and/or climate to do what they want. (L.E. Modesitt jr. I’m looking at you)

Walter Sobchak
January 19, 2021 6:27 pm

“examining computer simulations from 27 state-of-the-art climate models”

27! Wow. If they used 28, they would hve gotten the right answer.

January 20, 2021 2:11 am

Another masterclass in “look there’s a squirrel”.

According to the study, a northward shift of the tropical rain belt over the eastern Africa and the Indian Ocean will result in future increases of drought stress in southeastern Africa …

So they admit that the rain belt will shift north in Africa.
This shrinks the Sahara desert from the south.
Greening of the Sahara is good, not bad.
I’ve been saying for a long time that CO2 will cause – already is causing – the greening of the Sahara.
And that greening Sahara is good, not bad.

But these charlatans distract from these good effects of CO2 by jumping to hypothetical harmful effects elsewhere: notice in the above text there is zero acknowledgement of the implications of the “northward shift of the tropical rain belt over eastern Africa”.

wadelightly
January 23, 2021 12:27 pm

There was a time when all the earths continents were located in far away from their present location. Inexplicably they survived and continue to move in such a way millions of years from now they will be located far from where they currently reside. Crazy.