Amount of ocean heat found to be accelerating and fuelling extreme weather events

The amount of heat accumulating in the ocean is accelerating and penetrating ever deeper, with widespread effects on extreme weather events and marine life, according to a new scientific review.

More than 90% of the heat caused by adding greenhouse gases to the atmosphere through burning fossil fuels is taken up by the ocean.

The rate of warming in the top 2km has doubled from levels in the 1960s, the article in the journal Nature Reviews: Earth and Environment said.

According to the review the extra heat is accelerating sea level rise, intensifying extreme rain events, melting ice, adding energy to cyclones and changing where they form, and causing more intense marine heatwaves.

Marine habitats including coral reefs were being threatened and the heating meant oceans were less able to take carbon out of the atmosphere.

Fifteen scientists from Australia, New Zealand, China, the United Kingdom, France and the United States carried out the review which looked at historic changes in ocean temperatures at different depths and examined the results of climate models of future changes.

All ocean basins were getting hotter, but heating was most pronounced in the southern ocean and the Atlantic, the review found. From the 1990s, heating was also detected deeper than two kilometres.

He said the amount of rain seen in parts of Victoria in recent days was linked to the extra heat seen in the Coral Sea and the Tasman Sea.

At current rates, Trenberth said, the amount of energy being added to the ocean each year in the form of heat was equal to about 80 times the total global electricity generation.

Prof David Schoeman, of the University of the Sunshine Coast, was not involved in the review but was a co-ordinating lead author of the oceans chapter in the most recent UN climate report.

He said the review was broadly in line with previous UN assessments but had reduced the uncertainties and likely ruled out the highest and lowest predictions of changes in ocean heat.

Schoeman said marine heatwaves, made worse from global heating, had caused mass mortalities of marine plants and animals.