Global Warming Current Affairs

Volcanic carbon dioxide drove ancient global warming: Study

According to study conducted by researchers from University of Southampton, UK, extreme global warming event 56 million years ago was driven by massive carbon dioxide (CO2) emissions from volcanoes, during formation of North Atlantic Ocean.

They had used combination of new geochemical measurements and novel global climate modelling to show that Palaeocene-Eocene Thermal Maximum (PETM) was associated with rapid doubling of atmospheric CO2 in less than 25 thousand years because of CO2 emissions from volcanoes.

Key Facts

The PETM was most rapid and extreme natural global warming event of last 66 million years. It had lasted for around 150 thousand years and increased global temperatures by at least 5 degrees Celsius. Its period coincided with the formation of massive ‘flood basalts’ — large stretches of ocean floor coated in lava, resulting from of a series of huge eruptions.

Earlier it was suggested that PETM event was caused by injection of CO2 into ocean and atmosphere, but ultimate trigger source of CO2 was not known. Now researchers believe that, the CO2 was released during land drifts, separating Greenland from north-western Europe, thereby creating North Atlantic Ocean.

During this time, more than 10,000 petagrammes of CO2 was released predominantly from volcanic source. This is a vast amount of CO2, 30 times larger than all fossil fuels burned to date and equivalent to all current conventional and unconventional fossil fuel reserves.

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Sea ice hits record winter low at both poles: Scientists

According to US and European scientists, the extent of sea ice at both poles has hit new record lows for this time of the year.

The disappearing sea ice comes as the Earth marks three consecutive years of record-breaking heat and temperature rise, raising fresh concerns about the accelerating pace of global warming. 

Key Findings 
  • Artic region: The ice floating in the Arctic Ocean grows and shrinks on a seasonal cycle every year, reaching its largest size in March and smallest at the end of the summer melt in September.
  • But this year’s Arctic maximum spanned 14.42 million sq.km i.e. 95,829 sq.km below the previous record low in 2015. This year’s ice cover is 12,19,884 sq.km smaller compared to average sea ice extent for 1981-2010.
  • The Arctic sea ice maximum has dropped by an average of 2.8% per decade since 1979. There was a lot of open ocean water and very slow ice growth because the water had a lot of accumulated.
  • Antartic region: The ice in the Antarctic also follows a seasonal cycle but its maximum comes in September and its minimum around February (summer in Southern Hemisphere).
  • In the Antarctic, this year’s annual sea ice was 21,10,840 sq.km, about 1,83,889 sq.km below the previous lowest minimum extent in the satellite record, which occurred in 1997.
  • For the past two years, Antarctica saw record high sea ice extents and decades of moderate sea ice growth.

Ice level

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