Ozone-depleting chemicals decreasing in atmosphere, but weather plays big role in year-to-year variability
FRISCO — The ozone hole over Antarctica didn’t change much from last year, scientists said this week, pointing to weather and climate variability as key factors in year-to-year variability.
The single-day maximum area was similar to that in 2013, which reached 9.3 million square miles. The largest single-day ozone hole ever recorded by satellite was 11.5 million square miles) on Sept. 9, 2000. Overall, the 2014 ozone hole is smaller than the large holes of the 1998–2006 period, and is comparable to 2010, 2012, and 2013. Continue reading “Ozone hole about the same size as last year”→
FRISCO — Scientists say it’s unlikely that the Arctic will see ozone depletion on the scale of the Antarctic ozone hole, thanks mainly to international efforts to limit ozone-killing chemicals.
“While there is certainly some depletion of Arctic ozone, the extremes of Antarctica so far are very different from what we find in the Arctic, even in the coldest years,” said MIT atmospheric scientists Susan Solomon.
“It’s really a success story of science and policy, where the right things were done just in time to avoid broader environmental damage,” said Solomon, who made some of the first measurements in Antarctica that pointed toward CFCs as the primary cause of the ozone hole. Continue reading “Study assesses likelihood of Arctic ozone hole”→
Warmer stratosphere, active polar vortex help speed seasonal recovery
By Summit Voice
FRISCO — Relatively warm stratospheric temperatures helped limit the size of this year’s Antarctic ozone hole, which disappeared completely by Nov. 10, earlier than in recent years.
Using data gathered from ground stations and weather balloons, the World Meteorological Organization said the warmer temps at an elevation of about 20 kilometers limited the formation of polar stratospheric clouds which, through a chemical chain reaction between water, nitric acid and halogenated reservoir gases cause ozone loss. In this respect, the 2012 ozone hole was similar to the one in 2010, when a sudden stratospheric warming in July and August gave rise to a smaller amount of polar stratospheric clouds than usual. Continue reading “Environment: Antarctic ozone hole closes early this year”→
New study pinpoints regional growth and decline of Antarctic sea ice
By Bob Berwyn
FRISCO — After compiling more than 5 million individual daily ice motion measurements of sea ice motion around Antarctica, scientists from the U.S. and U.K. say they’re sure that the recent increases in Antarctic sea ice are linked to changing wind patterns in the region.
Essentially, the circumpolar winds are strengthening around Antarctica, said Dr. Ron Kwok, of NASA’s Jet Propulsion Laboratory in California. Why those winds are intensifying, and whether it’s linked with a warming atmosphere remains as a huge question, Kwok said. View a mult-year animation of Antarctic sea ice changes here.
“We are basically finding evidence of change over a long time scale … That’s why it’s inportant to quantify the mechanisms,” he said. “It’s probably associated with a changing climate. The Antarctic sea ice interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent.” Continue reading “Climate: Shifting winds drive Antarctic sea ice changes”→
Warmer temps in the lower stratosphere helped shrink the hole this year
By Summit Voice
FRISCO — The Antarctic ozone hole shrank to its second-smallest size in the past 20 years, down to “only” 8.2 million square miles, just barely big enough to cover all of North America.
NASA researchers said natural variations in weather patterns are the biggest factor in determining the size of the hole, which allows harmful ulraviolet radiation to reach the surface of the Earth. This year, those patterns generated warmer-than-average stratospheric temperatures in the region.
Trace radioactivity from nuclear test era helps researchers measure growth of rare Antarctic plants
By Bob Berwyn
SUMMIT COUNTY —Some of the earliest explorers racing each other to reach the South Pole found fossil fragments showing that lush forests once grew on Antarctica, when it was part of the supercontinent, Gondwanaland.
In this era, it’s difficult to find any signs of vegetation in Antarctica, but a few sparse patches of moss suggest that climate change in recent decades is having an impact on the few plants that do grow in the short summer season.