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The ‘Tug of War’ of Climate Change Keeps Scientists Guessing

A new study has found that human-induced climate change complicates projecting the future positioning of storms.  (Image:  NASA via   wikipedia /  CC0 1.0)
A new study has found that human-induced climate change complicates projecting the future positioning of storms. (Image: NASA via wikipedia / CC0 1.0)

Storm tracks — regions where storms travel from west to east across oceans and continents driven by the prevailing jet stream — determine weather and climate in middle-latitude places like Chicago and New York.

She is the lead author of “Storm track processes and the opposing influences of climate change,” a review of the latest research and current knowledge that was published Aug. 29 in Nature Geoscience.

In idealized and comprehensive climate model simulations, warming due to increased carbon dioxide concentration in the atmosphere leads the clouds in high latitudes to reflect more solar radiation, thereby cooling Earth’s surface in those regions and increasing the temperature gradient between the equator and the poles.

In insolation (the amount of solar energy reaching Earth’s surface) this would lead to a poleward shift of the storm tracks. Meanwhile, those same clouds tend to enhance the greenhouse effect, thereby warming Earth’s surface in those same regions, and decreasing the temperature gradient between the equator and the poles, producing an opposite shift (also, in insolation).

This is but one example of the opposing influences noted by the authors. Other examples include the opposing influence of warming in the tropical upper atmosphere and Arctic amplification (enhanced surface warming in the Arctic), both of which occur in models in response to climate change.

The most important message of this paper is that scientists are currently unable to satisfactorily project the response of storm tracks to anthropogenic climate change, said Edwin Gerber, associate professor of mathematics and atmosphere ocean science at New York University’s Courant Institute, who was not involved in the Nature Geoscience review.

The researchers called for expanding observational efforts and the hierarchy of computer simulations used to understand how storm tracks will shift in response to the increased concentration of carbon dioxide in the atmosphere.

Winners and losers

Ultimately, any major changes in the position of storm tracks will have a significant impact on society because storm tracks shape temperature, precipitation, and extreme weather.

Such shifts in position have the potential to significantly change patterns of rain, snow, heat waves, and cold outbreaks, Gerber said. For example, if storm tracks shift poleward, New York and Chicago will likely experience warmer weather and less snow.

And there’s already evidence that the shift of the austral storm track southward — which was caused by the ozone hole at the South Pole — has impacted rain in Australia and South America, he said, adding:

The Nature Geoscience review article grew out of a conference held last year that was sponsored by the National Science Foundation and The World Climate Research Program.

Provided by: University of Chicago

[Note: Materials may be edited for content and length.]

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