The heat in the world’s oceans reached a new record level in 2019, showing “irrefutable and accelerating” heating of the planet.
The world’s oceans are the clearest measure of the climate emergency because they absorb more than 90% of the heat trapped by the greenhouse gases emitted by fossil fuel burning, forest destruction and other human activities.
The new analysis shows the past five years are the top five warmest years recorded in the ocean and the past 10 years are also the top 10 years on record. The amount of heat being added to the oceans is equivalent to every person on the planet running 100 microwave ovens all day and all night.Hotter oceans lead to more severe storms and disrupt the water cycle, meaning more floods, droughts and wildfires, as well as an inexorable rise in sea level. Higher temperatures are also harming life in the seas, with the number of marine heatwaves increasing sharply.
The vast majority of oceans regions are showing an increase in thermal energy. This energy drives bigger storms and more extreme weather, said Prof John Abraham at the University of St Thomas, in Minnesota, US, and one of the team behind the new analysis.: “When the world and the oceans heat up, it changes the way rain falls and evaporates. There’s a general rule of thumb that drier areas are going to become drier and wetter areas are going to become wetter, and rainfall will happen in bigger downbursts.”
Hotter oceans also expand and melt ice, causing sea levels to rise. The past 10 years also show the highest sea level measured in records dating back to 1900.
Dan Smale, at the Marine Biological Association in the UK, and not part of the analysis team, said the methods used are state of the art and the data is the best available. “For me, the take-home message is that the heat content of the upper layers of the global ocean, particularly to 300 metre depth, is rapidly increasing, and will continue to increase as the oceans suck up more heat from the atmosphere,” he said.