The levels of greenhouse gases in the atmosphere have reached a new high: the UN

Before the COP 24 Climate Summit in Poland next month, senior UN officials are once again trying to pressure governments to respect their commitment to limit global warming to less than two degrees Celsius, registered in the Paris Agreement of 2015.

"Without rapid reductions in CO2 emissions and other greenhouse gases, climate change will have increasingly destructive and irreversible effects on life on Earth," said the President of the Organization. Petteri Taalas World Meteorological Council in a statement.

"The window of opportunity for the action is almost closed."

In an open letter to all states in advance of COP24, Michelle Bachelet, human rights officer at the United Nations, warned of catastrophic consequences if the world did not change course.

"Whole nations, ecosystems, peoples and lifestyles could simply cease to exist," she said, citing evidence that nations were not on the right track to respect the commitments made in Paris.

US President Donald Trump, who withdrew his government from the Paris agreement, again threw doubts on climate science Thursday.

"The cold, prolonged blast could shatter ALL THE RECORDS – What about global warming?" he said in a tweet.

Invited to respond to Trump, WMO Deputy Chief Elena Manaenkova told reporters that the science behind global warming was "unequivocal" without directly challenging the US leader.

5 million years

The Greenhouse Gas Bulletin, the flagship annual report of the United Nations Meteorological Agency, tracks the content of hazardous gases in the atmosphere since 1750.

This year's report, which covers data for 2017, estimates the concentration of CO2 in the atmosphere at 405.5 parts per million (ppm).

This represents an increase from 403.3 ppm in 2016 and 400.1 ppm in 2015.

"The last time the Earth experienced a comparable concentration of CO2, there are 3 to 5 million years, when the temperature was 2 to 3 ° C warmer," said Taalas.

Researchers have established reliable estimates of C02 levels dating back 800,000 years using air bubbles preserved in the ice of Greenland and Antarctica.

But by studying fossilized materials, the WMO has also established approximate estimates of CO2 up to five million years.

In addition to CO2, the UN agency has also highlighted rising levels of methane, nitrous oxide and another powerful ozone depleting gas called CFC-11.

& # 39; No magic wand & # 39;

Emissions are the main factor that determines the amount of greenhouse gases, but concentration levels are a measure of what remains after a series of complex interactions between the atmosphere, the biosphere, the lithosphere, the cryosphere and the oceans.

About 25% of all emissions are currently absorbed by the oceans and the biosphere, a term that refers to all the ecosystems on the planet. The lithosphere is the solid outer part of the Earth, while the cyrosphere covers this part of the world covered with frozen water.

The United Nations Intergovernmental Panel on Climate Change (IPCC) has stated that, in order to keep warming below 1.5 degrees Celsius, net emissions of CO2 must be zero. means that the quantity pumped into the atmosphere must be equal to the amount removed, whether it is natural or not. absorption or technological innovation.

Elena Manaenkova, Deputy Chief of WMO, said the CO2 remained in the atmosphere and the oceans for hundreds of years.

"There is currently no magic wand to remove any excess CO2 from the atmosphere," she said.

"Every fraction of global warming is important, as is every part of a million greenhouse gases," she said.

According to the UN, 17 of the 18 warmest years recorded since 2001, while the cost of climate-related disasters in 2017 exceeded 500 billion dollars (439 billion euros).

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The concentration of CO2 in the atmosphere reaches a record: the UN