Weaker Ocean Currents
A new study has found evidence that the ocean circulation in the North Atlantic has become the weakest of the past 1,500 years, mainly as a result of a warming climate.
Many climate models predict a weakening, or even a collapse, of this branch of the ocean circulation under global warming — partly due to a surge of fresh water from the melting of the Greenland ice sheet.
Researchers from the University of Hong Kong write in the journal Geophysical Research Letters that the Atlantic Meridional Overturning Circulation has far-reaching impacts on the climate from North America to Europe, and can influence the monsoon rainfall in South Asia and Africa.
CO2 Emissions Surge
Global emissions of the most prevalent greenhouse gas, carbon dioxide, rose to a new historic high last year, according to a U.N. report that warns the time for action to avoid disastrous climate change is running out.
It adds that emissions began rising again during 2017 for the first time in four years. Levels of accumulated atmospheric CO2 reached a global average of 405.5 parts per million during 2017, almost 50 percent higher than before the Industrial Revolution.
“The last time the Earth experienced a comparable concentration of CO2 was 3 to 5 million years ago, when the temperature was 2 to 3 degrees Celsius (3.6 to 5.4 F) warmer and sea level was 10 to 20 meters (33 to 66 feet) higher,” said World Meteorological Organization Secretary-General Petteri Taalas.