(Washington) Atmospheric concentrations of greenhouse gases responsible for climate change reached record highs in 2021, according to a scientific report which again shows that global warming “shows no signs of slowing down”.
Posted at 2:28 p.m.
“The data presented in this report is clear: we continue to see growing scientific evidence of the global impacts of warming, which shows no signs of abating,” commented Rick Spinrad, Administrator of the U.S. Observation Agency. Oceanic and Atmospheric (NOAA) whose scientists led this annual climate report.
“With many communities hit by floods that only happen every 1,000 years, exceptional droughts and historic heat this year, it shows that the climate crisis is not a threat to come but something we owe. face today,” he added.
In 2021, the concentration of CO2 in the atmosphere averaged 414.7 parts per million (ppm), 2.3 ppm higher than in 2020, according to the study published Tuesday in the journal of the American Meteorological Society. A record since the beginning of measurements and for at least a million years.
This record is not really a surprise. After the exceptional drop in 2020 with the COVID-19 crisis, emissions have largely started to rise again in 2021.
And in any case, the CO2 has an atmospheric lifetime of up to several hundred years.
Some scientists compare the atmosphere to a bathtub. Even if we reduce the flow of water discharged into it (emissions from human activities), the volume of evacuation (absorption of CO2 by plants) is simply not enough to compensate, and the tub continues to fill.
Levels of methane, a gas that lasts only ten years but has a warming power 80 times greater than CO2 over a 20-year period, also hit a record high, according to the NOAA statement, which noted a “significant” acceleration in the annual increase in methane levels in recent years.
“A planet getting smaller and smaller”
In terms of the consequences of global warming, for the tenth consecutive year, the average level of the oceans is also at a record level: 9.7 cm above the level of 1993, the year in which satellite measurements began.
The temperature of the oceans, which absorb most of the additional heat linked to global warming, has also never been so high.
And 2021 ranks among the six hottest years on record (5e or 6e according to measurements), despite a period marked by the La Niña phenomenon which causes cooling.
The report also highlights “well above average” cyclone activity in 2021, with 97 cyclones and typhoons large enough to name.
“If we take (this observation) seriously and use it wisely, it can help us to prosper on an increasingly small planet in terms of the impacts of our activities”, pleaded Paul Higgins, a manager of the American Meteorological Society.
The planet has gained an average of nearly 1.2°C since the pre-industrial era, already causing an increase in extreme weather events, from heat waves to storms, including droughts and floods.
And that’s just the beginning. While every tenth of a degree counts, the world is indeed heading towards a warming of +2.8°C by 2100 even if the commitments made by States under the Paris agreement are respected, according to the UN climate experts (IPCC).
This historic 2015 agreement aims to limit warming to well below +2°C, if possible +1.5°C. But to hope to meet even the least ambitious objective, between 2030 and 2050, emissions would have to be reduced each year as in 2020, an exceptional year when a good part of the world economy came to a standstill due to COVID- 19.