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Rise in summertime thunderstorms has been ‘robustly connected’ to climate change by scientists for the first time
- Warming in the Arctic has shifted temperature gradients across the globe
- There has led to a 13 per cent rise in storm-generating energy in the last 30 years
- The energy causing milder weather conditions has dropped by six per cent
- These changes are due to a redistribution of the electrical energy available
- Temperature changes are also fuelling a host of other anomalous conditions
A rise in summertime thunderstorms has been ‘robustly connected’ to climate change for the very first time by scientists at The Massachusetts Institute of Technology (MIT).
Using yearly data from 1979 to 2017, scientists from MIT calculated the change in the amount of energy that triggers storms across the globe.
They found that the electrical energy that fuels stormy weather had risen by 13 per cent, while that which cause milder ‘extratropical cyclones’, manifesting in wind and rain in the winter, dropped by six percent.
The redistribution is also driving a host of weather anomalies that include longer heat-waves spells, higher pollen counts and urban smog in the future, scientists said.
Electrical energy that fuels stormy weather rose by 13 per cent from 1979 to 2017, while those causing milder ‘extratropical cyclones’, which cause wind and rain, dropped by six per cent
The new study used yearly data from 1979-2017 to create a grid showing temperature and humidity conditions at different latitude points in the northern hemisphere.
This allowed scientists to chart changes in the atmosphere’s ‘horizontal temperature gradient’, the difference in temperatures between northern and southern latitudes.
The higher this gradient, the more energy there will be available to fuel extra-tropical cyclones.
With the Arctic in the northern hemisphere warming faster than the southern hemisphere in the last decades, the gradient has decreased and the amount of energy for extra-tropical cyclones has dropped by six per cent.
Dr Paul O’Gorman, an author of the study, said: ‘We can see how this energy goes up and down over the years, and we can also separate how much energy is available for convection, which would manifest itself as thunderstorms for example, versus larger-scale circulations like extratropical cyclones.’
In contrast, the amount of atmospheric electrical energy for storms rose by 13 per cent between the North Pole and Equator.
This means that significantly more energy was available to fuel thunderstorms and other local weather phenomenon related to high pressure systems since 1979.
The results mirror previous climate studies suggesting that summer winds associated with extratropical cyclones have decreased with global warming in the hemisphere.
With the Arctic in the northern hemisphere warming faster than the southern hemisphere in the last decades, the average temperature gradient between the northern and southern latitudes has decreased, and the amount of energy for extra-tropical cyclones has dropped by six per cent. This has been accompanied by a redistribution in energy that has seen an increase in the amount of energy that can fuel stormy weather in the northern hemisphere
Observations from Europe and Asia have also shown a strengthening of convective rainfall, such as from thunderstorms.
The researchers’ results estimate the average impact of global warming on summertime energy of the atmosphere over the Northern Hemisphere.
They now hope to be able to resolve this further, to see how climate change may affect weather in more specific regions of the world.
Professor O’Gorman said: ‘We’d like to work out what’s happening to the available energy in the atmosphere, and put the trends on a map to see if it’s, say, going up in North America, versus Asia and oceanic regions.
‘That’s something that needs to be studied more.’
The full findings were published in Proceedings of the National Academy of Sciences.
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