The seven years between 2015 and 2021 were probably the warmest on record, announced this Sunday (31) the WMO (World Meteorological Organization), in a report warning that the climate is entering “unknown territory”.
This annual report on the state of the climate “is based on the most recent scientific data that show that the planet is changing before our eyes”, said the UN secretary general, António Guterres, cited in the text.
“From the depths of the oceans to the tops of mountains, from melting glaciers to relentless extreme weather events, ecosystems and communities around the world are being destroyed,” he added.
The text, prepared from observations on the ground and by means of meteorological service satellites around the world, is published at the beginning of the UN Climate Change Conference, COP26, this Sunday (31).
The Scottish city of Glasgow hosts the conference, at which the international community is expected to step up its fight to limit global warming and, ideally, to a maximum of +1.5°C.
COP26 “must be a turning point for people and for the planet,” defended Guterres.
The report is based on historical records of temperatures on the planet and, in particular, uses the period 1850-1910, which the UN climate experts (IPCC) use as a basis for comparing with today.
Humanity is currently emitting far more than double the greenhouse gas emissions compared to that time.
However, these historical records do not take into account previous meteorological phenomena, which are recorded thanks to climatic paleontology.
Tom alarming
The tone of the WMO report is alarming, linking droughts, forest fires, large floods in different regions of the planet with human activity.
The year “2021 is less warm than recent years due to the influence of a moderate La Niña episode that occurred earlier in the year. La Niña has a temporary cooling effect on global average temperature and affects weather and climate conditions. . The La Niña brand was clearly observed in the tropical Pacific”, recalls the text.
However, the average temperature over the last 20 years has broken the symbolic barrier of +1°C for the first time.
“Persistent rainfall above the average recorded during the first half of the year in some parts of northern South America, especially in the north of the Amazon Basin, caused severe and long-lasting floods in the region,” the text adds.
And at the same time, “for the second year in a row, there were severe droughts that devastated much of the subtropical region of South America. Rainfall was below average in most of southern Brazil, Paraguay, Uruguay and northern Argentina.”
Experts acknowledge that they used a system of “quick attribution,” that is, the study of extreme natural events soon after they occur, to determine the extent to which they are the responsibility of human activity.
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“The IPCC has noted that there has been an increase in heavy rainfall in East Asia, but there is a low level of confidence in human influence,” the text acknowledges, for example.
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