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Concentrations of greenhouse gases that retain heat in the atmosphere have reached record levels.
The World Meteorological Organization (WMO) of the United Nations warned that there was no sign of reversing this trend, which is causing long-term climate change, raising the level of the sea and extreme weather conditions.
The average concentration of carbon dioxide (CO2) reached 405.5 parts per million (ppm) last year, a level unmatched for three to five million years.
Since 1990, greenhouse gas emissions have resulted in a 41% increase in total radiative forcing – a warming effect of the climate – by greenhouse gases.
CO2 accounts for about 82% of the increase in radiative forcing recorded over the past decade, according to figures from the US National Oceanic and Atmospheric Administration (NOAA) cited in the Bulletin of the United States. WMO
said WMO Secretary-General Petteri Taalas: "The science is clear. Without rapid reduction of CO2 and other greenhouse gases, climate change will have more and more destructive and irreversible impacts on life on Earth.
"The last time we experienced a comparable concentration of CO2 was 3 to 5 million years ago, when the temperature was 2 to 3 ° C warmer and the sea level was 10 at 20 meters.
Concentrations of methane and nitrous oxide have also increased and the discovery of a powerful destructive compound of ozone and greenhouse gases called CFC-11 has been discovered, which has been banned as it warms and destroys the planet. [19659002] Additional Information
Carbon Dioxide
Carbon dioxide is the main long-term greenhouse gas of the atmosphere. Concentrations reached 405.5 ppm in 2017, or 146% of the pre – industrial era (before 1750). The increase in CO 2 from 2016 to 2017 was about the same as the average growth over the last decade. It was lower than the record jump observed from 2015 to 2016 under the influence of a strong El Niño event, which triggered droughts in the tropics and reduced the ability of CO absorption by " wells "as forests and vegetation 2 . There was no El Niño in 2017.
Methane
Methane (CH 4 ) is the second largest greenhouse gas long-term and contributes around 17% to radiative forcing. . About 40% of methane is emitted into the atmosphere from natural sources (wetlands and termites) and about 60% comes from human activities such as livestock rearing, rice cultivation, agriculture, and animal husbandry. exploitation of fossil fuels, landfilling and biombad burning.
Atmospheric methane met a new high of about 1859 parts per billion (ppb) in 2017 and now accounts for 257% of the pre-industrial level. Its rate of increase was about equal to that observed over the last decade.
Nitrous oxide
Nitrous oxide (N 2 O) is released into the atmosphere from natural sources (about 60%) and anthropogenic sources (about 40%), including oceans, soils, biombad burning, fertilizer use and various industrial processes.
Its atmospheric concentration in 2017 was 329.9 parts per billion. This represents 122% of pre-industrial levels. It also plays an important role in the destruction of the stratospheric ozone layer that protects us from the harmful ultraviolet rays of the sun. It accounts for about 6% of radiative forcing due to long-lived greenhouse gases.
CFC-11
The Bulletin has a special section devoted to CFC-11 (trichlorofluoromethane). It is a potent greenhouse gas and a stratospheric ozone depleting substance regulated by the Montreal Protocol. Since 2012, its rate of decline has slowed to about two-thirds of its rate of decline over the previous decade. The most likely cause of this slowdown is the increase in emissions badociated with the production of CFC-11 in East Asia.
This discovery illustrates the importance of long-term measurements of atmospheric composition, such as those conducted by the Global Atmosphere Watch program, by providing observational-based information to support national inventories of climate change. Emissions and agreements on anthropogenic climate change, as well as for the recovery of the stratospheric ozone layer.
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