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Connecting the Hottest Hots and the Coldest Colds

Pam Sornson

Posted on January 30, 2019 19:03

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Between October 2018 and the beginning of February 2019, the planet demonstrated excruciating evidence of how climate change and global warming are affecting us all. Understanding the connection between higher surface temperatures and extreme weather events might move more people to reduce their contributions to the calamity the world is currently facing.

Millions of lives are currently disrupted by the sub-zero temperatures of the 'polar vortex' that has drifted down from the Arctic to cover much of the northeast and central regions of North America. At the same time, Australia's heat wave has been declared a national emergency as temperatures top 115°F, sparking fires and killing literally millions of wild animals.

The two temperature extremes are the latest examples of how atmospheric warming conditions are negatively affecting global weather systems. Understanding how increased atmospheric carbon levels are causing these phenomena should trigger ever-stronger actions to reduce those levels back down to a more tolerable range.

Why are we freezing and frying at the same time?

Earth's climate is driven by the jet streams, thin bands of strong winds high up in the atmosphere that form a border between hot and cold air and push the air masses that generate weather. Their strength, direction and consequent influences are affected by the seasons, air temperatures, and air pressure, so they change based on how those conditions are developing around the planet.

Until the Industrial Revolution, when atmospheric temperatures were relatively constant, the jet streams also flowed in a relatively consistent pattern. High above the poles, a 'vortex' - swirling winds miles above the surface - circled the region, containing those frigid air temperatures well to the north and south of civilization. Other jet streams circulated over the oceans, creating the global ocean conveyor belt of current that generates the Gulf Stream in the Atlantic and the Arctic Stream in the Pacific. On a seasonal basis, the combination of oceanic and atmospheric streams pulled colder air off the water to cool the planet in summer, acting like the planet's air conditioning system. Steady seasonal temperatures also maintained the course of the jet streams throughout the year, stabilizing the climate and regulating the weather accordingly.

Rising air temperatures are messing up the Jet Streams

Increasing air temperatures are playing havoc with the 'normal' courses of the jet and oceanic streams. As the air temperature has risen, the volume of warmer air in the atmosphere has also increased. At the same time, the oceans have been absorbing much of the excess heat generated by those higher temperatures so they, too, are warming. The formerly steady balance of colder and hotter air and water around the world is changing because of the increased levels of carbon in the atmosphere that trap and hold that extra heat. That change, in turn, is changing the direction, path, and impact of the jet streams.

Climate change in action

This year, the Arctic jet steam has veered off its 'normal' course and instead has sagged down over North America, dragging the frigid Arctic air down with it. At the same time, the now warmer water surrounding Australia can no longer cool the air above that continent, causing that country's hottest summer on record. 

At this point, we have no choice but to adapt to this 'new normal' of extreme weather.

Pam Sornson

Posted on January 30, 2019 19:03

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WASHINGTON | It might seem counterintuitive, but the vicious polar vortex is bringing its icy stranglehold to portions of...

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