Alarm sounded over the shrinking of frigid zones
Climate scientists have been warning of an increase in the frequency of extreme weather events, increased variability and instability of climatic patterns because of global warming.Updated: Jul 04, 2019 23:42 IST
The sea ice extent — a measure of the surface area of the ocean covered by ice — in both the Arctic and Antarctic has shrunk, proving right climate scientists’ warnings about the effect of global warming on the world’s frigid zones, according to new data released by scientific agencies.
Arctic sea ice extent in June was second lowest on record; the lowest was recorded in June 2016. Arctic sea ice extent in June averaged 10.53 million square kilometres, which is 1.23 million square kilometres below the 1981 to 2010 average and 120,000 square kilometres above the previous record in 2016, the US National Snow and Ice Data Center said in a study released on Tuesday.
Climate scientists have been warning of an increase in the frequency of extreme weather events, increased variability and instability of climatic patterns because of global warming.
The Snow and Ice Data Center also said the sea surface temperatures (SSTs) in the open waters of the Arctic have been unusually high, up to 5 degrees Celsius above average in the Chukchi Sea, a marginal area of the Arctic Ocean.
“Large areas of open water are now apparent in the Laptev and Kara seas with extent below average in Baffin Bay and along the southeast coast of Greenland,” it said.
And the World Meteorological Organization (WMO), in a statement on June 28, in the run-up to a UN climate meeting at Abu Dhabi, said the Antarctic sea ice extent was the smallest on record, and Arctic sea ice extent was the second smallest on record in May.
A new study published in the Proceedings of the National Academy of Sciences (PNAS) by the Cryospheric Sciences Laboratory at the NASA Goddard Space Flight Center on July 1 also red-flagged massive sea ice loss in the Antarctic.
Satellite observations of Antarctic sea ice coverage since the late 1970s have revealed that after a gradual increase in the Antarctic sea ice over decades until 2014, the trend suddenly reversed completely in the 2014- 2017 period. During 2014-2017, the rate of sea ice loss in the Antarctic far exceeded those recorded for the Arctic.
“Since then (2014), the decreases have been so great that the yearly averages for 2017 and 2018 are the lowest in the entire 1979–2018 record, essentially wiping out the 35 years of overall ice extent increases in just a few years,” the study by PNAS warned.
The Snow and Ice Data Center at the University of Colorado also said sea ice surrounding Antarctica was at the lowest mean monthly extent for June, surpassing 2002 and 2017. “While the recent decline is noteworthy, trends in Antarctic sea ice extent over the continuous satellite record since late 1978 remain slightly positive,” it said.
“The sea ice situation is a clear demonstration of greenhouse gas warming,” said Professor Paul Mayewski, director, Climate Change Institute, University of Maine. A paper he co-authored with Charles H Norchi from the University of Maine School of Law captures why sea ice loss in the Arctic is a warning of likely future disasters.
“Arctic warming and attendant sea ice decline have far reaching consequences for the climate of the Northern Hemisphere. The westerly flowing air that comprises the jet stream is getting wavier with Arctic warming… a wavier jet stream leads to greater persistence in seasonal patterns and an increased frequency of extreme events resulting in increased variability and instability in climate,” the paper said.
The paper referred to the Intergovernmental Panel on Climate Change (IPCC) models which suggest that Arctic warming will increase significantly, yielding a nearly year-round ice free Arctic Ocean by the end of the 21st century with a mean annual Arctic temperature rise of up to 8 degrees C and Arctic summer temperatures close to two times the present ones.
WMO, in its statement, also said the four warmest years on record were in the past four years, “and we are on track for 2015-2019 to be the warmest five years on record.
The warming trend continues unabated so far in 2019 and the months January to May were the third warmest such period on record.”