Written by Graham Readfearn
Courtesy of Guardian News & Media Ltd.
The temperature of the world’s ocean surface has hit an all-time high since satellite records began, leading to marine heatwaves around the globe, according to U.S. government data.
“The current trajectory looks like it’s headed off the charts, smashing previous records,” said Prof. Matthew England, a climate scientist at the University of New South Wales.
These past three years of La Niña conditions across the vast tropical Pacific have helped suppress temperatures and dampened the effect of rising greenhouse gas emissions.
But scientists said heat was now rising to the ocean surface, pointing to a potential El Niño pattern in the tropical Pacific later this year that can increase the risk of extreme weather conditions and further challenge global heat records.
La Niña periods — characterised by cooling in the central and eastern tropical Pacific and stronger trade winds — have a cooling influence on global temperatures. During El Niño periods, the ocean temperatures in those regions are warmer than usual and global temperatures are pushed up.
More than 90 percent of the extra heat caused by adding greenhouse gases to the atmosphere from burning fossil fuels and deforestation has been taken up by the ocean.
A study last year said the amount of heat accumulating in the ocean was accelerating and penetrating deeper, providing fuel for extreme weather. Hotter oceans provide more energy for storms, as well as putting ice sheets at risk and pushing up global sea levels, caused by salt water expanding as it warms.