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2023: A year of extreme climate

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There have already been all sorts of extreme weather this year in many parts of the world and undoubtedly there will be more to talk about in the coming months.  But the American Meteorological Society has recently published its State of the Climate report for 2023 and it was a year for the record books.

In 2023, the Earth’s layers of heat-reflecting clouds had the lowest extent ever measured.  That means that skies were clearer around the world than on average, a situation that amplifies the warming of the planet.  Since 1980, clouds have decreased by more than half a percent per decade. 

The most dramatic climate effect last year occurred in the world’s oceans.  About 94% of all ocean surfaces experienced a marine heatwave during the year.  The global average annual sea surface temperature anomaly was 0.13 degrees Celsius above the previous record set in 2016.  This is a huge variation for the ocean.  Ocean heatwave conditions stayed in place for at least 10 months in 2023 in vast reaches of the world’s oceans.  Ocean heat was so remarkable that climate scientists are now using the term “super-marine heatwaves” to describe what is going on. 

There were many other ways in which 2023 experienced weather extremes.  July experienced a record-high 7.9% of the world’s land areas in severe drought conditions.  During the year, most of the world experienced much warmer-than-average conditions, especially in the higher northern latitudes.  These unprecedented changes to the climate are unlikely to be one-time occurrences; 2024 is likely to be another one for the record books.  

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New Federal Report Details More of 2023’s Extreme Climate Conditions

Photo, posted May 27, 2021, courtesy of Wendy Cover/NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Shrinking African glaciers

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We don’t usually associate Africa with glaciers, but the continent has had glaciers on its highest peaks for the past 10,000 to 15,000 years.  Africa’s glaciers are found in three regions:  the Rwenzori Mountains along the border between Uganda and the Democratic Republic of the Congo, Mount Kilimanjaro, and Mount Kenya.  At the turn of the 20th century, there were 43 glaciers scattered across 6 peaks within the Rwenzori Mountains.  In the intervening years, things have greatly changed.

 Since the early 20th century, Africa’s glaciers have shrunk by 90%.  Because all these glaciers are close to the equator, they are especially vulnerable to warming.  According to a new study published in the journal Environmental Research: Climate, in the last two decades, Africa’s glaciers have lost roughly half their area.

This rapid decrease is alarming to climate scientists because they represent a clear indicator of the impact of climate change.  A major factor in the decline of the glaciers is the reduction in cloud cover over the mountains.  Sunshine is melting glaciers and turning ice directly into water vapor even when temperatures are below freezing.  Reductions in snowfall at the same time means that the melting glaciers are not being replenished.

Scientists believe that the tropical glaciers of Africa may all but disappear over the next 25 years.

Roughly three-quarters of the Earth’s freshwater is stored in the world’s more than 200,000 glaciers.  According to scientists, if the world reaches but maintains 1.5 degrees of warming, half of the world’s glaciers could be gone by the end of this century.  If the world continues to warm as it has been without slowing down, more than 80% of the glaciers will disappear.

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Africa’s Tropical Glaciers Have Shrunk by 90 Percent, Research Shows

Photo, posted February 26, 2022, courtesy of Ray in Manila via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greenland Becoming Darker | Earth Wise

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According to research published by Dartmouth University, a weather pattern that pushes snowfall away from parts of Greenland’s ice sheet is causing the continent to become darker and warmer.

Reducing the amount of fresh, lighter-colored snow exposes older, darker snow on the surface of Greenland’s ice sheets.  Fresh snow is the brightest and whitest. The reflectivity of snow decreases fairly quickly as it ages. This decrease in albedo – or reflectivity – allows the ice sheet to absorb more heat and therefore melt more quickly. 

The research attributes the decrease in snowfall in Greenland to a phenomenon called atmospheric blocking in which persistent high-pressure systems hover over the ice sheet for up to weeks at a time.  Such systems have increased over Greenland since the mid-1990s.  They push snowstorms to the north, hold warmer air over Western Greenland, and reduce light-blocking cloud cover.

All of this contributes to Greenland melting faster and faster.  According to research cited in the study, the Greenland ice sheet has warmed by nearly 5 degrees Fahrenheit since 1982.  Overall, Greenland is experiencing the greatest melt and runoff rates in the last 450 years, at the minimum, and quite likely the greatest rates in the last 7,000 years.

The Greenland ice sheet is the second largest ice body in the world, after the Antarctic ice sheet.  It is 1,800 miles long and about 700 miles wide at its greatest width.  Its thickness is between 1.2 and 1.9 miles.  If the entire sheet were to melt, it would lead to a global sea level rise of 24 feet.  So, the darkening of Greenland is a source of great concern.

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Greenland Becoming Darker, Warmer as Snow Changes

Photo, posted April 3, 2012, courtesy of Francesco Paroni Sterbini via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)