"Our climate is changing before our eyes," warns the head of the World Weather Organization, Petteri Taalas. Four important indicators for climate change will reach their highest values in 2021. The 1.5 degree limit is also getting closer.
Four key indicators of climate change have hit record highs, according to the World Weather Organization's (WMO) new climate status report. The WMO reported in Geneva that this underscores the devastating consequences of human activities for the ecosystems that are supposed to ensure the survival of mankind. Records have been set for sea level rise, ocean heat content, ocean acidification and the concentration of greenhouse gases in the atmosphere. This is mainly carbon dioxide (CO2).
The WMO confirmed its preliminary calculation that the global average temperature in 2021 was about 1.1 degrees above the pre-industrial level (1850-1900) and the past seven years were the warmest on record. She had already touched on this worrying development in her preliminary status report in October. At that time, however, not all measured values were available. According to a WMO forecast last week, the global annual average temperature could be more than 1.5 degrees above the pre-industrial level by 2026 at least in one year. The probability of this is almost 50 percent. The hottest year so far was 2016 with 1.2 degrees above pre-industrial levels.
"Our climate is changing before our eyes," said WMO chief Petteri Taalas. The man-made 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 methods are invented to remove carbon from the atmosphere," said Taalas. Nevertheless, the WMO emphasizes that 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 concentration of greenhouse gases in the atmosphere is at a record high. In 2020, this reached the record value of 413.2 ppm (parts per million particles). The average figure for 2021 is not yet available. But the Mona Loa station in Hawaii reported 416.45 ppm in April 2020, 419.05 ppm in April 2021 and 420.23 ppm in April 2022.
Another indicator is ocean acidification. According to the WMO, the oceans absorb around 23 percent of man-made greenhouse gases. The gases react 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 additional 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.
The WMO also warned of the rising 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.
The organization is also concerned about rising sea levels. Contributing to this are the thermal expansion of seawater due to warming of the oceans and the increase in water volume due to the melting of ice on land. 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.