Global average sea surface temperatures last month reached unprecedented levels for June. The north Atlantic Ocean recorded exceptionally warm sea surface temperatures, with several extreme marine heatwaves. These were related to short term changes in atmospheric circulation and longer-term changes in the ocean, according to analysis from the Copernicus Climate Change Service (C3S*).
So far this year, discussions of our oceans and climate have largely focused on the onset of El Niño, recently
declared by the World Meteorological Organization, and its potential for pushing global temperatures into “uncharted territory” by the end of 2023 and into 2024. But in fact, we have already entered uncharted territory due to the exceptionally warm conditions in the north Atlantic Ocean.
« The temperatures in the North Atlantic are unprecedented and of great concern. They are much higher than anything the models predicted, » said Dr
Michael Sparrow, head of WMO’s World Climate Research Department. “This will have a knock on effect on ecosystems and fisheries and on our weather, » he said.
“The North Atlantic is one of the key drivers of extreme weather. With the warming of the Atlantic there is an increasing likelihood of more hurricanes and tropical cyclones. North Atlantic sea surface temperature is associated with heavy rain or drought in West Africa,” said Dr Baddour.
The marine heatwaves observed during June were likely a result of a combination of the short-term anomalous atmospheric circulation and longer-term changes, including variations in circulation and heat transport in the Atlantic, and the
warming of our oceans due to climate change. Globally,
mean sea surface temperature has increased, and continues to increase, since the pre-industrial era,
while 90% of the extra heat associated with global warming has been taken up by the oceans.
The warm sea surface temperatures in the north Atlantic also impacted the Atlantic hurricane season, which officially began on 1 June, and has already seen three named storms, including two simultaneously, which is
exceptionally rare for June.
The world just had the hottest week on record, according to preliminary data. It follows the hottest June on record, with unprecedented sea surface temperatures and record low Antarctic sea ice extent.
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