Four key climate change indicators have reached record levels, according to the World Meteorological Organization’s (WMO) new State of the Climate report.
This underscores the devastating consequences of human activities on the ecosystems that are supposed to ensure humanity’s survival, the WMO reported this morning in Geneva.
Records were set for sea level rise, ocean heat content, ocean acidification and atmospheric concentrations of greenhouse gases. These are mainly carbon dioxide (CO2).
The WMO confirmed its preliminary calculation that the global average temperature in 2021 was about 1.1 degrees above pre-industrial levels (1850-1900), and that the past seven years were the warmest on record.
Average temperature in 2021 about 1.1 degrees above pre-industrial levels
It had already touched on this worrying development in its preliminary status report in October. At that time, however, not all measured values were available.
According to a WMO forecast from last week, the global annual average temperature could be more than 1.5 degrees above the pre-industrial level in at least one year by 2026.
The probability of this happening is nearly 50 percent, it said. The hottest year to date was 2016, when temperatures were 1.2 degrees above pre-industrial levels.
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„Our climate is changing before our eyes,“ said WMO chief Petteri Taalas. Man-made greenhouse gases in the atmosphere are preventing the Earth’s heat from radiating into space, so the planet will continue to heat up for generations „unless methods are invented to remove carbon from the atmosphere,“ Taalas said.
Nevertheless, the WMO stresses, it is important to reduce the amount of greenhouse gases released now to keep warming permanently below 1.5 degrees above pre-industrial levels.
CLIMATE IS CHANGING BEFORE OUR EYES
Turning to the concentration of greenhouse gases in the atmosphere, it reached a record 413.2 ppm (particles per million particles) in 2020. The average figure for 2021 is not yet available. But the Mona Loa monitoring station in Hawaii reported 416.45 ppm in April 2020, 419.05 ppm in April 2021 and 420.23 ppm in April 2022.
WMO study: oceans are acidifying more and more / Photo by Matt Hardy on Unsplash
ON OCEAN ACIDIFICATION:
The oceans absorb about 23 percent of man-made greenhouse gases, according to the WMO. The gases react with the water, leading to acidification. This not only threatens the marine ecosystem. In addition, the more acidic the water, the lower its capacity to absorb further CO2. The pH value indicates acidification. The lower it is, the more acidic the water.
The Intergovernmental Panel on Climate Change (IPCC) recently reported that the pH at the surface of the open oceans is almost certainly lower now than it has been for at least 26,000 years.
Regarding the heat content of the oceans, a near-global system of floating gauges has only been in place since 2006, and prior to that, the data was less good.
However, all research groups working on this issue agree that the heat content down to a depth of 2,000 meters has been increasing for decades, and particularly markedly since 2016.
SEA LEVEL RISE:
Contributing factors include thermal expansion of seawater due to ocean warming and increased water volume due to melting of ice on land. According to the WMO, the rise was about 2.1 millimeters per year between 1993 and 2002, and 4.5 millimeters per year between 2013 and 2021.