Monday December 10, 2018
Home Science & Technology NASA: Earth&#...

NASA: Earth’s Ozone Hole Shrinks to Smallest Since 1988

0
//
NASA
NASA: Earth's Ozone Hole Shrinks to Smallest Since 1988 (VOA)
Republish
Reprint

Washington: The ozone hole over Antarctica shrank to its smallest peak since 1988, NASA said Thursday. The huge hole in Earth’s protective ozone layer reached its maximum this year in September, and this year NASA said it was 7.6 million square miles (19.6 million square kilometers). The hole size shrinks after mid-September.

This year’s maximum hole is more than twice as big as the United States, but it’s 1.3 million square miles smaller than last year and 3.3 million square miles smaller than 2015.

FILE - A false-color view of total ozone over the Antarctic pole is seen in this NASA handout image released Oct. 24, 2012. The purple and blue colors are where there is the least ozone. The average area covered by the Antarctic ozone hole in that year was the second smallest in two decades, at 8.2 million square miles; in September 2017, it was 7.6 million square miles.

[ FILE – A false-color view of total ozone over the Antarctic pole is seen in this NASA handout image released Oct. 24, 2012. The purple and blue colors are where there is the least ozone. The average area covered by the Antarctic ozone hole in that year was the second smallest in two decades, at 8.2 million square miles; in September 2017, it was 7.6 million square miles ].

Paul Newman, chief Earth scientist at NASA’s Goddard Space Flight Center, said stormy conditions in the upper atmosphere warmed the air and kept the chemicals chlorine and bromine from eating ozone. He said scientists haven’t quite figured out why some years are stormier — and have smaller ozone holes — than others.

“It’s really small this year. That’s a good thing,” Newman said.

Newman said this year’s drop is mostly natural but is on top of a trend of smaller steady improvements likely from the banning of ozone-eating chemicals in a 1987 international treaty. The ozone hole hit its highest in 2000 at 11.5 million square miles (29.86 million square kilometers).

Ozone is a colorless combination of three oxygen atoms. High in the atmosphere, about 7 to 25 miles (11 to 40 kilometers) above the Earth, ozone shields Earth from ultraviolet rays that cause skin cancer, crop damage and other problems.

Scientists at the United Nations a few years ago determined that without the 1987 treaty, by 2030 there would have been an extra 2 million skin cancer cases. They said that overall, the ozone layer is beginning to recover because of the phase-out of chemicals used in refrigerants and aerosol cans. (VOA)

Click here for reuse options!
Copyright 2017 NewsGram

Next Story

Wintertime Ice Growth in Arctic Sea Slows Long-Term Decline: NASA

The switch will happen once the sea ice is less than 1.6 feet thick at the beginning of winter, or its concentration

0
NASA, tissue
Wintertime ice growth in Arctic sea slows long-term decline: NASA. Flcikr

While sea ice in the Arctic continues to be on the decline, a new research from the US Space agency NASA suggests that it is regrowing at faster rates during the winter than it was a few decades ago.

The findings showed that since 1958, the Arctic sea ice cover has lost on average around two-thirds of its thickness and now 70 per cent of the sea ice cap is made of seasonal ice, or ice that forms and melts within a single year.

But at the same time, that sea ice is vanishing quicker than it has ever been observed in the satellite record, it is also thickening at a faster rate during winter.

This increase in growth rate might last for decades, explained the researchers, in the paper to be published in the journal Geophysical Research Letters.

However, this does not mean that the ice cover is recovering, though. Just delaying its demise.

“This increase in the amount of sea ice growing in winter doesn’t overcome the large increase in melting we’ve observed in recent decades,” said lead author Alek Petty, a sea ice scientist at NASA’s Goddard Space Flight Center in Maryland.

NASA, Hubble, Keplar, asteroids
However, this does not mean that the ice cover is recovering, though. Just delaying its demise. Flickr

“Overall, thickness is decreasing. Arctic sea ice is still very much in decline across all seasons and is projected to continue its decline over the coming decades,” she added.

To explore sea ice growth variability across the Arctic, the team used climate models and observations of sea ice thickness from the European Space Agency’s CryoSat-2 satellite.

They found that in the 1980s, when Arctic sea ice was on average 6.6 feet thick in October, about 3.3 extra feet of ice would form over the winter.

This rate of growth may continue to increase, and in the coming decades, we could also have an ice pack that would on average be only around 3.3 feet thick in October, but could experience up to five feet of ice growth over the winter.

Also Read- Apple Releases its New Beddit 3.5

However, by the middle of the century, the strong increases in atmospheric and oceanic temperatures will outweigh the mechanism that allows ice to regrow faster, and the Arctic sea ice cover will decline further, Petty said.

The switch will happen once the sea ice is less than 1.6 feet thick at the beginning of winter, or its concentration — the percentage of an area that is covered in sea ice — is less than 50 per cent, she noted. (IANS)