A quadruple increase in carbon dioxide over East Asia causes changes in both fast and slow cloud responses

A quadruple increase in CO2 over East Asia causes changes in both fast and slow cloud responses
Clouds provide a large feedback to the processes that cause global warming. Credit: Hua Zhang

Extreme climate warming has been shown to change how cloud cover behaves throughout East Asia (EA). Recent research suggests that in a warmer climate with greater amounts of CO2 in the atmosphere, slow cloud responses to meteorological mechanisms can cause a cooling effect over certain regions of EA. However, in some areas within Asia, fast cloud responses may have the opposite effect. This new dynamic is concerning to climatologists who are working to better understand how CO2 and clouds interact.

"Clouds play an important role in balancing the radiation budget, and they have a large feedback on caused by the increase of greenhouse gases," said Prof. Hua Zhang, a at the Chinese Academy of Meteorological Sciences. "The uncertainty of cloud feedback has the most impact out of all the climate feedbacks."

Prof. Zhang and her team—a group of researchers from Chinese Academy of Meteorological Sciences, University of Chinese Academy of Sciences, and Beijing Climate Center have recently published a comprehensive cloud-climate feedback study in Advances in Atmospheric Sciences.

"We can obtain the clouds' responses to increased greenhouse gases from and divide the feedback into fast responses with time scales of days to months and slow responses with time scales of years to decades," continued Dr. Zhang.

In the study, scientists separated fast and slow cloud responses to an abrupt atmospheric CO2 quadrupling over EA. They used a general circulation model, BCC_AGCM2.0, developed by the China Meteorological Administration to obtain quantitative data.

The study also considers a total cloud response, which contains the following components: the total cloud cover (TCC), low cloud cover (LCC), and high cloud cover (HCC). All of these variables showed an increase north of 40°N and a decrease south of 40°N with the exception of the Tibetan Plateau (TP).

Within the total cloud response, the mean changes of the TCC, LCC, and HCC over EA are –0.74%, +0.38%, and –0.38%, respectively. The fast responses are generally opposite of the slow responses. Furthermore, the total responses are dominated by the slow responses, but in the case of the TP, the fast response determines the HCC change.

Under the quadrupled CO2 warming scenario, the mean net cloud forcing (NCF) over EA is –1.80 Watts per meter squared (W m–2), indicating a alongside a slow cloud response. Scientists suggest that this can partially offset the warming effect caused by quadrupled CO2concentrations. That said, the NCF over the TP, south China, and northeast China are –6.74 W m–2, 6.11 W m–2, and –7.49 W m–2, respectively, which can offset or potentially amplify the climate warming effect much more noticeably.

"Studying cloud responses to quadrupled CO2 over EA provides a better understanding of the changes and effects of clouds under extreme warming in the future," said Prof. Zhang, "and our research especially reveals the role of the slow response of clouds."

More information: Xixun Zhou et al, Decomposition of Fast and Slow Cloud Responses to Quadrupled CO2 Forcing in BCC-AGCM2.0 over East Asia, Advances in Atmospheric Sciences (2022). DOI: 10.1007/s00376-022-1441-7

Journal information: Advances in Atmospheric Sciences

Citation: A quadruple increase in carbon dioxide over East Asia causes changes in both fast and slow cloud responses (2022, September 23) retrieved 21 June 2024 from https://phys.org/news/2022-09-quadruple-carbon-dioxide-east-asia.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Explore further

Studying short-term cloud feedback to understand climate change in East Asia

6 shares

Feedback to editors