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Earth's cryosphere is shrinking by 87,000 square kilometers per year


beecee

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https://phys.org/news/2021-07-earth-cryosphere-square-kilometers-year.html

The global cryosphere—all of the areas with frozen water on Earth—shrank by about 87,000 square kilometers (about 33,000 square miles, an area about the size of Lake Superior) per year on average between 1979 and 2016, as a result of climate change, according to a new study. This research is the first to make a global estimate of the surface area of the Earth covered by sea ice, snow cover and frozen ground.

The extent of land covered by frozen water is just as important as its mass because the bright white surface reflects sunlight so effectively, cooling the planet. Changes in the size or location of ice and snow can alter air temperatures, change the sea level and even affect ocean currents worldwide.

The new study is published in Earth's Future, AGU's journal for interdisciplinary research on the past, present and future of our planet and its inhabitants.

 

more at link..............

the paper:

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020EF001969

A Holistic Assessment of 1979–2016 Global Cryospheric Extent

Abstract:

The cryosphere plays a major role in earth’s climate system. Most cryospheric assessments focus on one or more of its components and their response to climate change. However, to date, there has not been a comprehensive evaluation of the entire global cryosphere. We therefore determine such a holistic estimate and quantify changes to the hemispheric and global cryosphere due to climate change, by synthesizing sea ice, snow cover, and frozen ground extents into one global cryospheric extent dataset. The 1981–2010 climatology of daily global cryospheric extent ranges from 45.7±0.7×106 to 87.2±2.0×106 km2 (9.0%–17.1%), from 13.3±0.8×106–66.3±1.7×106 km2 (5.2%–26.0%) in the Northern Hemisphere (NH), and from 17.9±0.3×106 to 33.6±0.4×106 km2 (7.0%–13.2%) in the Southern Hemisphere (SH). The monthly maximum cryospheric extent of 85.84±1.91×106 km2 occurs in December, whereas minimum occurs in July with 45.92±0.70×106 km2. During 1979–2016, global cryospheric area extent lost approximately 87±11×103 km2/yr, with a decrease of 102±9.7×103 km2/yr in the NH that was partly offset by an increase of 14.6±4.4×103 km2/yr in the SH. The first day of cryospheric cover was delayed by 3.6 days at a rate of 0.95 days/decade, and the last day advanced by 5.7 days, at a rate of 1.5 days/decade. The duration and number of cryospheric cover days decreased by 8.7 days and 7.6 days over the study period, respectively. These variations of global cryospheric extent are correlated with rising air temperatures. Our findings highlight the importance of assessing the cryosphere as a whole, and provide a way to quantitatively estimate its overall changes.

 

Supplementary article............

https://phys.org/news/2021-07-183c-antarctica.html

UN confirms 18.3C record heat in Antarctica:

The United Nations on Thursday recognised a new record high temperature for the Antarctic continent, confirming a reading of 18.3 degrees Celsius (64.9 degrees Fahrenheit) made last year.

The record heat was reached at Argentina's Esperanza research station on the Antarctic Peninsula on February 6, 2020, the UN's World Meteorological Organization said.

The World Meteorological Organization confirmed a record high temperature for Antarctica at the Esperanza Base on February 6, 20

more at link............

Edited by beecee
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In terms of climatic tipping points,  it seems to me the media have not brought the importance of albedo change sufficiently to the public's attention.  Both temp rise and particulate deposition on ice fields (diesel soot,  dust, and so on) seem to be major players in ice shrinkage.  Those are scary numbers (but these days what numbers,  in climatological data,  aren't scary?).  

 

The potential effect on the AMOC,  of dumping lots of cold glacial melt in to the North Atlantic,  is also something that Europe needs to be crisis planning for.   Especially UK,  which dips its feet right in the middle of the AMOC.   

 

Thanks for posting this.   

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