Researchers are sounding the alarm: the four most important indicators of climate change have reached record levels. This is shown by the new climate status report from the World Weather Organization (WMO). Records have been set for sea level rise, ocean warming, ocean acidification and the concentration of greenhouse gases in the atmosphere. The latter is mainly carbon dioxide (CO₂).
The WMO confirmed that the global average temperature in 2021 was about 1.1 degrees above the pre-industrial level (1850 to 1900) and the past seven years were the warmest on record.
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According to the WMO, the concentration of greenhouse gases in the atmosphere reached a record value of 413.2 ppm (parts per million particles) in 2020. The average figure for 2021 is not yet available.
Regarding the acidification of the seas, it is said that the oceans absorb around 23 percent of man-made CO2 emissions. The gas reacts with the water, causing acidification. This not only threatens the ecosystem of the sea. In addition, the more acidic the water, the lower the capacity to absorb more CO₂. The pH value indicates the acidification.
The lower it is, the more acidic the water. The Intergovernmental Panel on Climate Change (IPCC) recently reported that the surface pH of the open oceans is very likely to be at its lowest level in at least 26,000 years.
Regarding the heat content of the oceans: An almost global, area-wide system with floating measuring devices has only existed since 2006. Before that, the data situation was less good. However, all research groups working on this agree that the heat content down to a depth of 2000 meters has been increasing for decades, particularly since 2016.
Regarding sea level: This rises because seawater expands due to warming oceans and the water volume increases due to melted ice. According to the WMO, the increase was about 2.1 millimeters per year between 1993 and 2002, and 4.5 millimeters per year between 2013 and 2021.
“Our climate is changing before our eyes,” said WMO chief Petteri Taalas. The greenhouse gases in the atmosphere prevent the earth from radiating heat into space, which is why the planet will continue to heat up for generations “unless processes are invented to remove carbon from the atmosphere”.
Nevertheless, it is important to reduce the amount of greenhouse gases released now in order to keep warming below 1.5 degrees above pre-industrial levels.
The world community agreed on this goal back in 2015 with the Paris Climate Agreement. International climate protection should limit the consequences of the climate crisis, such as more extreme heat, longer droughts and more floods. These effects are significantly smaller with global warming of 1.5 degrees than with two degrees. The second mark corresponds to the less ambitious climate target in the Paris Agreement.
According to a WMO forecast from mid-May, the global annual average temperature could at times be more than 1.5 degrees above the pre-industrial level by 2026. The probability of this is almost 50 percent.
With regard to the WMO climate report, UN Secretary-General António Guterres criticized “humanity’s pitiful failure to combat the climate crisis” and called for seizing the opportunities in the energy transition and breaking the “dead end” of fossil fuels.
“Renewables are the only path to energy security, stable energy prices and opportunities for sustainable jobs,” Guterres said in a video message on the occasion of the report. “If we act together, the transition to renewable energies can be the peace project of the 21st century.”
