0.5DEGC of additional warming has a huge effect on global aridity

Date:
September 17, 2020
Source:
Institute of Industrial Science, The University of Tokyo
Summary:
In a simulation study, researchers showed that limiting global
warming to 1.5DEGC rather than 2DEGC will mitigate aridification
in some regions of the world including the Mediterranean, western
Europe, and southern Africa. However, Australia and some parts
of Asia were simulated to become wetter rather than drier at both
1.5DEGC and 2DEGC of warming.

These findings reveal the importance of targeted regional
simulations of aridity levels to support policymaking decisions
on global warming targets.



FULL STORY ==========================================================================
In a new climate modeling study, researchers from the Institute
of Industrial Science, The University of Tokyo have revealed major
implications for global drought and aridity when limiting warming to
1.5DEGC rather than 2DEGC above pre-industrial levels. Drought has
serious negative impacts on both human society and the natural world
and is generally projected to increase under global climate change. As
a result, assessment of the risk of drought under climate change is a
critical area of climate research.


==========================================================================
In the 2015 Paris Agreements, the United Nations Framework Convention
on Climate Change (UNFCCC) proposed that the increase in global
average temperature should be limited to between 1.5DEGC and 2DEGC
above pre-industrial levels to limit the effects of severe climate
change. However, there have been few studies focusing on the relative importance of this 0.5DEGC of global average temperature rise and what
effect it might have on drought and aridity around the world.

"We wanted to contribute to the understanding of how important that
0.5DEGC could be, but it such a study is not easy to conduct based on
previous modeling approaches," explains corresponding author Hyungjun
Kim. "This is mainly because most models look at the extreme high levels
and you cannot simply take a slice out of the data while the model spins
up to this maximum. Therefore, we used data from the specially designed
Half a degree Additional warming Prognosis and Projected Impacts (HAPPI) project to assess the impacts on aridity based on estimations of the
balance between water and energy at the Earth's surface." The study
revealed that 2DEGC of warming led to more frequent dry years and more
severe aridification in most areas of the world compared with 1.5DEGC,
which emphasizes that efforts should be made to limit warming to 1.5DEGC
above pre-industrial levels.

"There is a really strong message that some parts of the world could
have more frequent drought at 2DEGC than at 1.5DEGC. This situation
could be especially severe in the Mediterranean, western Europe,
northern South America, the Sahel region, and southern Africa," says lead author Akira Takeshima. "However, this situation is highly regional. In
some parts of the world, like Australia and some of Asia, the opposite situation was simulated, with a wetter climate at 2DEGC than at 1.5DEGC."
These findings show the importance of considering the regional impacts
of the additional 0.5DEGC of warming, especially with respect to any
future relaxation of the 1.5DEGC target.


========================================================================== Story Source: Materials provided by Institute_of_Industrial_Science,_The_University_of_Tokyo.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Akira Takeshima, Hyungjun Kim, Hideo Shiogama, Ludwig Lierhammer,
John F
Scinocca, O/yvind Seland, Dann Mitchell. Global aridity changes
due to differences in surface energy and water balance between 1.5
DEGC and 2 DEGC warming. Environmental Research Letters, 2020; 15
(9): 0940a7 DOI: 10.1088/1748-9326/ab9db3 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200917105348.htm

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