Dhe year 2020 is likely to be one of the three warmest since temperature records began in the middle of the 19th century, according to preliminary analyzes by the World Weather Organization (WMO) – and the previous decade the warmest ever. The six warmest years since the measurements began were all in the period since 2015. For Europe, the average temperature in the first ten months was even higher than ever before. The organization reported on Wednesday in its preliminary report on the state of the climate in 2020. The main cause of accelerated warming is the increase in greenhouse gases. A week ago, the WMO reported a new historical high for greenhouse gas levels in the atmosphere for the past two years.
The current temperature forecasts relate to meteorological measurements from January to October. During these months the global average temperature was 1.11 to 1.23 degrees Celsius above the average for the years 1850 to 1900. The measurement results north of the Arctic Circle in Siberia were particularly drastic: the temperature there was more than five degrees above from January to October the average from 1981 to 2010. According to the WMO, the global temperature rise could temporarily exceed 1.5 degrees by 2024. Five years ago, in the Paris Agreement on Climate Change, the international community committed itself to limiting global heating to 1.5 degrees as possible. In the coming week everyone wants to celebrate the 5th anniversary of the climate protection agreement.
Climate change has meanwhile also become the greatest threat to world natural heritage sites worldwide. Global warming is a “high or very high threat” in a third of the areas, as the World Conservation Union (IUCN) also reported on Wednesday. In 2014 this was only the case for a quarter. The corona pandemic is also making itself felt, mostly negative, according to the IUCN. Without tourists, money for rangers in national parks would be lacking in many places and illegal activities flourished.
The Wadden Sea habitat on the North Sea is also one of the World Heritage Sites affected. The warming and rising sea levels endanger it as a breeding ground for migratory birds. The chances of survival of the world natural heritage are nevertheless good – if the ongoing conservation and protection measures are continued. The scientists are sounding the alarm at the world’s largest coral reef, the Great Barrier Reef off Australia. The IUCN now assesses the prospects of survival as “critical”. The warming and acidification of the sea leads to the death of the corals.
In addition to Europe, according to the WMO, it was also very warm in the southwest of the United States, in western South America and in parts of Central America. Canada, parts of Brazil, northern India and southeast Australia, on the other hand, experienced cooler temperatures than average.
The mean global sea level has risen by an average of 3.3 millimeters per year since measurements began in 1993. A slight decline in 2020 – as in 2011 – is probably due to the natural climate phenomenon La Niña, but that does not change the long-term trend. During the La Niña months, more rain falls in tropical river areas than over the sea, which temporarily lowers the mean sea level globally. La Niña should still be felt until spring 2021, according to the WMO. Since 1993, sea levels have risen most sharply in the southern hemisphere east of Madagascar, New Zealand and South America.
One of the reasons for sea level rise is melting ice near the North and South Poles. Greenland lost around 152 gigatons (billion tons) of ice from September 2019 to August 2020. That was less than in 2019, when 329 gigatons melted. The WMO warns: “The Arctic is experiencing drastic changes as global temperatures rise. Since the mid-1980s, temperatures there have been rising at least twice as fast as the global mean. “
In the Arctic, the extent of sea ice in July and October was lower than ever since the measurements began, according to the WMO. The minimum ice extent was 3.74 million square meters in September and was the second smallest (after 2012) that was ever measured. The floating ice of the Arctic does not contribute to sea level rise when it melts. However, the earth warms up faster if instead of ice, the light reflects, melts and dark water surfaces are exposed.
Sea levels are also rising because the increasing concentration of greenhouse gases in the atmosphere leads to excess energy in the earth system, a large part of which is absorbed by the oceans. The sea water becomes warmer and expands.
The hurricane season in the North Atlantic saw more severe storms this year than ever before. It usually ends on November 30th. Parts of Africa and Asia experienced heavy rain and flooding, including the Sahel region, the Horn of Africa, the Indian subcontinent, as well as China, the Korean Peninsula, Japan and parts of Southeast Asia. In contrast, northern Argentina, Paraguay and western Brazil experienced severe droughts in South America.