Oceans hit record heat, acidity in 2021: UN report

A diver inspects transplanted coral near Dibba Port in Fujairah, United Arab Emirates on June 15, 2020.

Christopher Pikes | Reuters

The oceans reached their warmest and most acidic levels on record last year, the World Meteorological Organization said Wednesday, marking one of the main consequences of climate change due to human-induced greenhouse gas emissions.

The results were part of a larger annual report which he detailed how four primary measures of climate change – greenhouse gas concentrations, sea level rise, ocean temperatures and ocean acidification – hit record highs in 2021.

“Our climate is changing before our eyes,” said WMO General Secretary Petteri Taalas said in a statement. “The heat trapped by human-induced greenhouse gases will warm the planet for many generations to come.”

The oceans have been particularly affected by rising greenhouse gas emissions and temperatures. In fact, much of the ocean experienced at least one “strong” sea heatwave at some point last year, according to the report.

Such extreme temperatures have put critical marine ecosystems such as coral reefs, seagrass beds and kelp forests at risk of collapse. Rapid ocean warming has also triggered a decline in global fish populations.

The WMO also confirmed that pH levels in the oceans have reached their lowest point in at least 26,000 years. As the oceans become more acidic, their ability to absorb carbon dioxide from the atmosphere decreases.

Sea level also hit record highs last year after rising an average of 4.5mm annually over the past decade, the WMO said. It is more than double the rate observed between 1993 and 2002 and is mainly due to the accelerated loss of ice mass due to the melting of ice sheets. Rising sea levels put hundreds of millions of coastal residents at risk from more intense and frequent storms and floods, the WMO warned.

“Sea level rise, ocean heat and acidification will continue for hundreds of years unless means are invented to remove carbon from the atmosphere,” Taalas said.

Scientists have warned that the world has already warmed about 1.1 degrees Celsius above pre-industrial levels and that global temperatures will rise 2.4 degrees Celsius by 2100. The past seven years have been the seven warmest years ever. sign in.

UN Secretary-General António Guterres in a statement criticized “the sad litany of humanity’s inability to tackle climate change” and called for urgent action to grab the “low fruit” of shifting energy systems away from fuels. fossils that warm the planet with renewable energy.