Climate teleconnections intensified over last 37 years; southern hemisphere more vulnerable
Teleconnections describe how climate events such as wildfires and floods in one part of the world can affect weather thousands of kilometers away. Photo: iStock The links between weather phenomena at widely separated locations on earth, also called climate teleconnections, are increasingly getting stronger globally. These teleconnections have affected the southern hemisphere more prominently over the last 37 years, according to the paper published in Chaos An Interdisciplinary Journal of Nonlinear Science.
Teleconnections describe how climate events such as wildfires and floods in one part of the world can affect weather thousands of kilometers away.
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“Think of it [teleconnections] as a domino effect on a global scale,” Jingfang Fan of Beijing Normal University and the Potsdam Institute for Climate Impact Research said in a statement. He is also the co-author of the study.
Teleconnections have garnered significant attention due to their role in energy transport and global-scale climate dynamics occurring over typically thousands of kilometres. They exist both in the atmosphere and the ocean, the authors wrote.
Fan and his colleagues analysed climate networks to gain insights into the intensity, distribution and evolution of teleconnections.
The climate network was based on the National Center for Environmental Prediction / National Center for Atmospheric Research’s reanalysis of daily surface or near the surface. The dataset covers a time period of 74 years, from January 1948 to December 2021.
They used global daily surface air temperature data to look at the directions and distribution patterns of teleconnections. Advanced data processing and mathematical algorithms helped them investigate the intensity of teleconnections and identify sensitive regions.
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The regions most vulnerable to teleconnections were in southeastern Australia and South Africa, the analysis showed.
The southern hemisphere is more vulnerable because it is largely covered by oceans, which contribute to more stable teleconnections and Rossby wave or planetary wave formation.
Rossby waves occur in oceans and the atmosphere. They naturally occur due to the Earth’s rotation and help transfer heat from the tropics towards the poles and cold air towards the tropics.
The northern hemisphere, on the other hand, has more complex terrain, environmental pollution and forest fires caused by human activities, which makes Rossby waves unstable. Teleconnections are mainly dominated by atmospheric Rossby waves, the research suggested.
The Rossby waves are also affected by the Arctic amplification – caused by shrinking the sea ice and exposing the ocean. The ocean, thus, absorbs more heat and leads to more warming. Studies have shown the Arctic has warmed either twice or even three times faster than the global average.
The intensity of teleconnections over the last 37 years consistently exceeded that of the first 37 years, the study also pointed out. This could be due to a confluence of factors such as climate change, human activities, and other factors.
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Fan warned that the Earth may see temperatures rise over the next five years to levels that global scientists had previously warned. “It’s like the planet is running a fever that’s steadily getting worse,” he noted. The year 2023 is predicted to be the hottest on record.
The team hopes the findings will help predict weather events. “The next step is like weather forecasting – but on steroids,” Fan explained. “Using what we have learned, we plan to predict how climate events will unfold and connect. We are diving deep to explore why these events happen and how various climate ‘tipping points’ within our climate system might be linked,” he added.
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