Friday October 18, 2019
Home Lead Story Banned Chemic...

Banned Chemical Responsible For Antarctic Ozone Hole

After considering a number of possible causes, researchers concluded that CFC emissions must have increased after 2012.

0
//
Emissions of a banned chemical most responsible for the giant Antarctic ozone hole are on the rise, according to a study which suggests that an international treaty that required an end to its production in 2010 is being violated.
Ozone Hole Representational Image. Pixabay

Emissions of a banned chemical most responsible for the giant Antarctic ozone hole are on the rise, according to a study which suggests that an international treaty that required an end to its production in 2010 is being violated.

Trichlorofluoromethane, or CFC-11, is the second-most abundant ozone-depleting gas in the atmosphere and a member of the family of chemicals most responsible for the giant hole in the ozone layer that forms over Antarctica each September.

Once widely used as a foaming agent, production of CFC-11 was phased out by the Montreal Protocol in 2010.

The new study, published in the journal Nature, documents an unexpected increase in emissions of this gas, likely from new, unreported production.

“We’re raising a flag to the global community to say, ‘This is what’s going on, and it is taking us away from timely recovery from ozone depletion,'” said Stephen Montzka, scientist at the US National Oceanic and Atmospheric Administration (NOAA).

“Further work is needed to figure out exactly why emissions of CFC-11 are increasing and if something can be done about it soon,” said Montzka.

CFCs were once widely used in the manufacture of aerosol sprays, as blowing agents for foams and packing materials, as solvents, and as refrigerants.

Though production of CFCs was phased out by the Montreal Protocol, a large reservoir of CFC-11 exists today primarily contained in foam insulation in buildings, and appliances manufactured before the mid-1990s. A smaller amount of CFC-11 also exists today in chillers.

Since CFC-11 still accounts for one-quarter of all chlorine present in today’s stratosphere, expectations for the ozone hole to heal by mid-century depend on an accelerating decline of CFC-11 in the atmosphere as its emissions diminish – which should happen with no new CFC-11 production.

Emissions of a banned chemical most responsible for the giant Antarctic ozone hole are on the rise, according to a study which suggests that an international treaty that required an end to its production in 2010 is being violated.
Chemical Emission is the main reason of the hole in Ozone layer above Antarctica. Pixabay

Despite the increase in CFC-11 emissions, its concentration in the atmosphere continues to decrease, but only about half as fast as the decline observed a few years ago, and at a substantially slower rate than expected.

This means that the total concentration of ozone-depleting chemicals, overall, is still decreasing in the atmosphere. However, that decrease is significantly slower than it would be without the new CFC emissions.

Precise measurements of global atmospheric concentrations of CFC-11 made by scientists at 12 remote sites around the globe show that CFC-11 concentrations declined at an accelerating rate prior to 2002 as expected.

Then the rate of decline hardly changed over the decade that followed. Even more unexpected was that the rate of decline slowed by 50 per cent after 2012.

Know About Glow Plugs: How Glow Plugs Work 

After considering a number of possible causes, researchers concluded that CFC emissions must have increased after 2012.

This conclusion was confirmed by other changes recorded in NOAA’s measurements during the same period, such as a widening difference between CFC-11 concentrations in the northern and southern hemispheres – evidence that the new source was somewhere north of the equator.

Measurements from Hawaii indicate the sources of the increasing emissions are likely in eastern Asia. More work will be needed to narrow down the locations of these new emissions, Montzka said. (IANS)

Next Story

Amount of Ice Circling Antarctica Plunges from Record High to Record Lows

Floating ice off the southern continent steadily increased from 1979 and hit a record high in 2014

0
Ice, Antarctic, Scientists
FILE - An iceberg floats in Andvord Bay, Antarctica, Feb. 14, 2018. VOA

The amount of ice circling Antarctica is suddenly plunging from a record high to record lows, baffling scientists.

Floating ice off the southern continent steadily increased from 1979 and hit a record high in 2014. But three years later, the annual average extent of Antarctic sea ice hit its lowest mark, wiping out three-and-a-half decades of gains — and then some, a NASA study of satellite data shows.

In recent years, “things have been crazy,” said Mark Serreze, director of the National Snow and Ice Data Center. In an email, he called the plummeting ice levels “a white-knuckle ride.”

Serreze and other outside experts said they don’t know if this is a natural blip that will go away or more long-term global warming that is finally catching up with the South Pole. Antarctica hasn’t showed as much consistent warming as its northern Arctic cousin.

Ice, Antarctic, Scientists
The amount of ice circling Antarctica is suddenly plunging from a record high to record lows, baffling scientists. Pixabay

“But the fact that a change this big can happen in such a short time should be viewed as an indication that the Earth has the potential for significant and rapid change,” University of Colorado ice scientist Waleed Abdalati said in an email.

At the polar regions, ice levels grow during the winter and shrink in the summer. Around Antarctica, sea ice averaged 4.9 million square miles (12.8 million square kilometers) in 2014. By 2017, it was a record low of 4.1 million square miles (10.7 million square kilometers, according to the study in Monday’s Proceedings of the National Academy of Sciences.

The difference covers an area bigger than the size of Mexico. Losing that much in just three years “is pretty incredible” and faster than anything scientists have seen before, said study author Claire Parkinson, a NASA climate scientist.  Antarctic sea ice increased slightly in 2018, but still was the second lowest since 1979. Even though ice is growing this time of year in Antarctica, levels in May and June this year were the lowest on record, eclipsing 2017, according to the ice data center.

Ice melting on the ocean surface doesn’t change sea level. Non-scientists who reject mainstream climate science often had pointed at increasing Antarctic sea ice to deny or downplay the loss of Arctic sea ice.

Also Read- Scientists Say Cigar-Shaped Interstellar Object Not an Alien Spaceship

While the Arctic has shown consistent and generally steady warming and ice melt — with some slight year to year variation — Antarctica has had more ups and downs while generally trending upward. That is probably in part due to geography, Parkinson and Serreze said.

The Arctic is a floating ice cap on an ocean penned in by continents. Antarctica is just the opposite, with land surrounded by open ocean. That allows the ice to grow much farther out, Parkinson said.

When Antarctic sea ice was steadily rising, scientists pointed to shifts in wind and pressure patterns, ocean circulation changes or natural but regular climate changes like El Nino and its southern cousins. Now, some of those explanations may not quite fit, making what happens next still a mystery, Parkinson said. (VOA)