august

Missing Antarctic Sea Ice | Earth Wise

August 30, 2023 By EarthWise Leave a Comment

It is summer here in the United States, but it is winter in Antarctica. Antarctic sea ice is water that forms and melts entirely in the ocean and it has a pattern of growth and reduction that has been monitored by satellites for the past 44 years. The area of sea ice that surrounds the continent of Antarctica is known as the sea ice ‘extent’ and it had been quite stable for much of those years.

In 2016, the sea ice extent began to decline. Since then, there have been several record summer lows with both the summers of 2021/22 and 2022/23 setting new minimum records.

This August, the deviation from all previous records intensified. This winter’s sea ice extent is over 900,000 square miles below the long-term average, an area about the size of Greenland or, for example, Texas and Alaska combined.

Climate models have long predicted that Antarctic sea ice would reduce as a result of global warming but the current change to sea-ice extent is so dramatic that it is difficult to explain. Sea ice extent is affected by multiple factors including the El Niño Southern Oscillation, the strength of the southern hemisphere jet stream, and regional low-pressure systems. The warming climate is certainly the overall force that is changing Antarctic sea ice extent over time.

Antarctic sea ice extent is important because it covers a vast area of the dark Southern Sea with a bright white surface that reflects the sun’s energy back into space, helping to reduce temperatures at the pole and protecting glaciers and polar ice sheets.

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The mystery of the missing Antarctic sea ice

Photo, posted November 7, 2016, courtesy of Rob Oo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Death Valley Flooding | Earth Wise

September 13, 2022 By EarthWise Leave a Comment

Furnace Creek in Death Valley is the driest place in North America. Its average annual rainfall is under two inches. On August 5th, a thousand-year rainfall event dropped 1.46 inches of rain – about three-quarters of a year’s precipitation. The all-time record for a single day is 1.47 inches, set in April 1988. The storm did break the record for the most rain ever recorded in August, which averages just over a tenth of an inch of rain for the entire month.

The flash flood washed debris over roads, swept away and buried cars, knocked a water facility offline, damaged buildings, and stranded about a thousand visitors and staff in Death Valley National Park. By the next day, the flood water had mostly receded, and stranded visitors could be escorted out of the park by National Park personnel.

Death Valley sits at 282 feet below sea level. If it were not for the extremely arid climate there, Death Valley would likely be filled with water. However, humid air masses traveling east from the Pacific Ocean have to cross four mountain ranges before they reach the desert valley. Those air masses lose their moisture in the form of rain on the western slopes of the mountain, leaving a dry area, or rain shadow, on the eastern sides. By the time the air masses reach Death Valley, they are bone dry. On rare occasions, the lowest spot in the valley fills with water forming a wide, shallow lake, known as Lake Badwater.

The extreme heat and aridity of Death Valley evaporates the temporary lake quickly, returning the valley to its usual state. Furnace Creek still holds the record for the highest air temperature ever recorded: 134 degrees Fahrenheit.

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Death Valley Flash Flooding

Photo, posted April 7, 2021, courtesy of Matthew Dillon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Heatwaves And Alpine Mountain Climbing | Earth Wise

August 25, 2022 By EarthWise Leave a Comment

From June to August, there were persistent heat waves affecting parts of Europe that caused wildfires, evacuations, and heat-related deaths. Nearly 12,000 people died from heat stroke or other causes associated with the high temperatures. The highest temperature recorded during this period was 116.6 degrees F in Pinhao, Portugal on July 14th. The RAF base in Coningsby, Lincolnshire recorded a temperature over 104 degrees on July 19th, the highest ever recorded in the United Kingdom.

Among the effects of the multiple European heatwaves has been the cancellation of climbing tours up some of the most iconic peaks in the Alps, including Mont Blanc and the Matterhorn. The high temperatures and rapidly melting glaciers have made the climbing routes too dangerous. Overall, climbing cancellations occurred on about a dozen peaks, including the Jungfrau in Switzerland, which cancelled tours for the first time in a century.

In previous years, during warm summers, some of these climbing routes were closed in August, but the glaciers were already in a condition that usually only happens at the end of summer or even later.

The combination of heat and glacier melt can be treacherous. In July, 11 people were killed at Italy’s Marmolada glacier by falling ice and rock.

Glacial melt in the Alps is rapidly accelerating. The Forni Glacier, the largest valley glacier in Italy, has retreated two miles since 1860 and its area has shrunk by half. Forecasts are that it will retain only 20% of its current volume by 2050 and may disappear entirely by the end of the century. Half of the 4,000 glaciers in the Alps are expected to disappear by 2050.

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European Heat Waves Force Closure of Classic Climbing Routes in Alps

Photo, posted September 4, 2020, courtesy of Dmitry Djouce via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.