The concentration of greenhouse gases in the atmosphere, responsible for climate change, reached record levels in 2021, according to a scientific report that once again shows that global warming “shows no signs of slowing down”, reports AFP.

“The data presented in this report is clear: We continue to see increasing scientific evidence of global warming impacts that show no signs of slowing,” commented Rick Spinrad, administrator of the US National Oceanic and Atmospheric Administration (NOAA). , whose scientists led the annual climate report.

“Given that this year many communities have been affected by once-in-a-thousand-year floods, exceptional droughts and historic heatwaves, this shows that the climate crisis is not a threat to the future, but something we have to face. today,” he added.

Atmospheric CO2 concentrations averaged 414.7 parts per million (ppm) in 2021, up 2.3 parts per million from 2020, according to a study published Tuesday in the Journal of the American Meteorological Society. This is a record since the beginning of measurements and for at least a million years.

However, the record is not a surprise. After an exceptional reduction in emissions in 2020 due to the Covid-19 crisis, they increased significantly again in 2021.

And in any case, CO2 lives in the atmosphere for up to several hundred years.

Some scientists compare the atmosphere to a bathtub. Even if you reduce the flow of water entering it (emissions from human activity), the volume of water leaving (CO2 absorption by plants) simply isn’t enough to compensate, and the tub continues to fill.

Levels of methane, a gas that lasts only a decade but has 80 times the warming capacity of CO2 over a 20-year period, also reached record levels, according to a NOAA statement, marking a “significant” acceleration in annual growth. increase in methane levels in recent years.

A smaller and smaller planet

As for the effects of global warming, the average ocean level is also at a record level for the tenth year in a row: 0.97 cm above the level of 1993, when satellite measurements began.

The temperature of the oceans, which absorb most of the additional heat from warming, is also at a record high.

And 2021 is one of the six warmest years on record (fifth or sixth, depending on the measurement), despite the La Niña cooling period.

The report also highlights “well above average” cyclone activity in 2021, with 97 cyclones and typhoons large enough to be named.

“If we take (this discovery) seriously and use it wisely, it can help us thrive on a planet that is becoming smaller and smaller in terms of the impact of our activities,” said Paul Higgins, an official spokesman for the American Meteorological Society.

Since the pre-industrial era, the planet has warmed by almost 1.2 °C on average, which has already caused an increase in extreme weather events, from heat waves to storms, droughts and floods.

And this is just the beginning. While every tenth of a degree matters, according to UN climate experts (IPCC), the world is indeed headed for a warming of +2.8°C by 2100, even if countries meet their commitments under the Paris Agreement.

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 target, emissions must be reduced every year between 2030 and 2050, as was the case in 2020, an exceptional year when much of the global economy ground to a halt due to Covid-19.