Antarctica’s last 6 months were the coldest on record
By Allison Chinchar, CNN meteorologist
In a year of extreme heat, Antarctica’s last six months have been the coldest on record.
“For the period of polar darkness, April through September, the average temperature was -60.9 degrees Celsius (-77.6 degrees Fahrenheit), a record for those months,” National Snow and Ice Data said. Center (NSIDC).
The last six months are also the darkest time at the South Pole, hence the name polar darkness (also known as polar night). Here, the sun sets for the last time around the spring equinox and does not rise again until around the fall equinox six months later.
For the entire Antarctic continent, the winter of 2021 was the second coldest on record, with the ‘temperature for June, July and August 3.4 degrees Celsius (6.1 degrees Fahrenheit) below the 1981 average. to 2010 at -62.9 degrees Celsius (-81.2 degrees Fahrenheit), ”according to a new report from the NSIDC.
“This is the second coldest winter (June-July-August) on record, behind only 2004 in the 60-year weather record at Amundsen-Scott station at the South Pole,” said the NSIDC.
“The unusual cold has been attributed to two extended periods of stronger than average circling winds around the continent, which tend to isolate the ice sheet from warmer conditions,” the NSIDC explained. “A powerful polar vortex in the upper atmosphere has also been observed, leading to a large hole in the ozone layer. The ozone hole appears to have peaked from this message, with early measurements indicating that it is in the top quartile (top 25%) of ozone layer depletion events since 1979. “
Even during the southern summer months from November to February, it never gets really “hot” at the South Pole. The Amundsen-Scott station at the South Pole, which sits at an elevation of 2,835 meters (9,300 feet), has an average monthly temperature of -28 ° C (-18 ° F) during the austral summer.
The National Science Foundation, which manages the US Antarctic program, points out that winter temperatures have had minimal impact on scientific support for the South Pole, as most of the in-depth fieldwork takes place during the austral summer. However, polar environments are still difficult.
“Everyone cope with the cold differently, and the equipment today makes it much safer than when Shackleton and the other explorers had little specialized equipment; they only had woolen socks and leather shoes to protect their feet! an NSF spokesperson said. “All participants in the NSF’s US Antarctic Program (USAP) are provided with extremely cold weather gear and trained in how to recognize the dangers of extreme cold. “
An extremely cold winter is intriguing from a record-keeping standpoint, but one season alone doesn’t change the long-term progression, which is rapid warming.
Weather vs climate
It is important to understand that the weather is different from the climate. Weather is what happens over shorter periods (days to months), such as a seven-day forecast. Climate is what happens over much longer periods of time, like several years, or even entire generations.
“One such example is a cold snap, which can occur due to sudden changes in atmospheric circulation and may not be related to climate change,” says Tom Slater, a researcher at the Center for Polar Observation and Modeling at the University of Leeds. “Texas is a good example; although parts of it experienced extreme cold earlier this year when arctic air was pushed south, looking at the long-term temperature change tells us that Texas is on average 1.5 degrees warmer than 100 years ago. It’s the climate.
Scientists also agree that since the 1950s extreme cold spells have occurred, but climate change brings many more record heat than record cold.
“In other words, while the globe may be warmer than average as a whole, some regions will still see colder temperatures and even severe cold outbreaks,” says Zack Labe, climate scientist at Colorado State. University. “This regional variation is due to influences from oceans, mountains, deserts, ice caps and other geographic features that all affect our weather and climate. It is also because of changes in weather conditions that are related to the position of the jet stream (trajectory of storms), which can vary from day to day or even from month to month.
So this recent winter period from June to August is certainly interesting from a research perspective, but it doesn’t necessarily reflect what Antarctica is doing in the long run.
A good example of this is that while June-August of this year may have been quite cold, February of the previous year set the new all-time record for the Antarctic continent. On February 6, 2020, the Esperanza research station recorded an elevated temperature of 18.3 ° C (64.9 ° F). This broke the previous record for the Antarctic region (mainland, including mainland and surrounding islands) of 17.5 ° C (63.5 ° F) recorded in March 2015 at the same station.
“There were thousands upon thousands of these penguins just in distress because they were so overheated and there was no snow,” Camille Seaman, a photographer who visited, told CNN. Antarctica in August. “They were looking for any small patch of snow or ice to lay on.”
What happens at one pole does not mean that it happens at the other.
Thanks to the extreme cold near the South Pole, the extent of the Antarctic sea ice has been above average in recent months, peaking at the end of August when it reached 5th in satellite records.
However, the ice near the North Pole did just the opposite.
The summer of 2021 has been relatively cool near the North Pole compared to many recent years, according to the NSIDC, allowing the September ice extent to be the highest since 2014.
However, while this may sound good, keep in mind that the past 15 years (2007 to 2021) had the 15 lowest September ice areas on record.
The extent of the Arctic sea ice in September averaged 1.90 million square miles (4.92 million square kilometers), making it the 12th lowest in 43 years of record keeping.
Literally everywhere else is heating up
What is happening at the poles of the Earth does not mean that it is happening all over the world as well.
“Although global temperatures have risen by about 1.1 degrees over the past 150 years on average, different parts of the globe have warmed at different rates due to natural variations in the climate system such as cloud cover, land cover and atmospheric circulation patterns, ”Slater mentioned.
“The Earth’s poles have warmed faster than anywhere else, mainly due to melting ice and snow. Although Antarctica has experienced a cold winter this year, in recent decades the northernmost parts of Antarctica have warmed five times faster than the global average, i.e. faster than everywhere else in the southern hemisphere.
As scientists take note of the changes taking place at the Earth’s poles, the greatest danger lies in the most populous continents where people live and work.
“As a climatologist, I am particularly alarmed at how extreme heat waves, such as the one that hit the Pacific Northwest this summer, are expected to become more frequent in the future,” Labe said. “But right now we have a great opportunity. We can help reduce the severity and frequency of future extreme heat waves (and global climate change) by systematically reducing our consumption of fossil fuels.
The impact on humans and animals is central to the climate crisis.
“Extreme heat and humidity can present serious health risks to those who have to endure them – on average, the world now experiences 14 more days per year with temperatures of 45 ° C compared to 40 years ago. years, ”Slater said. “This is why I hope that we will see countries strengthen their commitments in the fight against climate change at COP26 in just a few weeks. “
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