sciencetech-blog

comments

Global warming could be triggering increasingly cold winters in some parts of the world, scientists have claimed.

Researchers have discovered a link between rising ocean temperatures, and a large pocket of cold air known as the polar vortex.

They discovered that as oceans heat up and melt the Arctic ice, warm air is released that destabilises polar air and sends cold blasts into the atmosphere.

Researchers claim the most recent polar vortex (illustrated) was caused by melting polar ice, which was melted by warmer ocean temperatures. This caused warm air to destabilise the polar air and send cold air into the atmosphere. And as global warming continues to heats oceans, freezing winters could increase

The polar vortex was responsible for the extreme and freezing temperatures experienced in the US last winter.

A polar vortex is a large pocket of very cold air that sits above the polar region during the winter months.

During winter this air chills and contrasts with the warmer temperatures further away from the pole.

Pressure contrasts between these temperatures create fast winds that swirl around the pocket of cold air. 

Researchers, led by Baek-Min Kim from Korea Polar Research Institute, compared recent weather trends and reports, with computer models.

The modelling was designed to reveal what Earth would look like if it hadn't experienced any Arctic ice loss.

They discovered that the polar ice is melting because warmer water is travelling up the Gulf Stream from tropical regions of the Atlantic Ocean towards Scandinavia and other areas of Europe.

In particular, the water is causing 'exceptional sea ice melt' in the Barents-Kara seas.

This melting leads to areas of open water, which release heat into the atmosphere during winter months.

In turn they found this causes the northern jet stream to weaken and move further south, taking cold, polar air with it.

The warmer temperatures cause the colder, polar temperatures to destabilise and emit cold blasts into the atmosphere.

Due to its location, Canada and the US in particular, faced the brunt of this cold air in more recent winters.

But Eurasia is likely to also see the cooling effect impacting on winters.

The polar vortex (illustrated) was blamed for extreme and freezing temperatures in the US this winter. It is a large pocket of cold air that sits above the polar region. During winter, this air gets cold, and contrasts with temperatures further away. Pressure contrasts between these temperatures to create fast winds

Researchers, led by Baek-Min Kim from Korea Polar Research Institute, compared statistical analysis of recent weather trends, including freezing temperatures in the midwest of the US (pictured), with computer modelling. The modelling was designed to see what Earth would look like if it hadn't experienced Arctic ice loss

And, if global warming continues to raise ocean temperatures, the chances of more extreme winter weather will increase, claim the researchers.

The study was published in the journal Nature Communications.

Earlier this year global warming was blamed for the 'irreversible retreat' of west Antarctic glaciers.

But scientists recently claimed that warming of the planet is in fact behind a paradoxical growth in South Pole sea ice.

They believe the shift is caused by water melting from beneath the Antarctic ice shelves and re-freezing back on the surface.

Earlier this week, reports even claimed sea ice cover in the Antarctic is now at its highest level since records began.

This graphic shows trends in sea ice duration between 1979 and 2010. It shows large regional variations. Rather than disproving global warming, some scientists claim that a recent growth in sea ice may in fact be caused by westerly winds, created by an increase in greenhouse gases

Satellite images revealed 7.7 million square miles (20 million sq km) of ice surrounding the continent.

But rather than disproving global warming, scientists claim that this growth may in fact be caused by it.

The first theory is that westerly winds, which flow around Antarctica, are speeding up and moving south. 

This is thought to be linked to an increase in greenhouse gases and an increase in sea ice.

The second theory is that sea ice forms easier due to the colder and fresher melt water from Antarctica's melting glaciers and ice sheets.