Record greenhouse gases

Greenhouse gases in the atmosphere rose to record levels in 2020 despite a decrease in new emissions due to the pandemic, jeopardizing the effort to cap rising temperatures


Roughly half of CO2 emitted by human activities remains in atmosphere. Half is absorbed by “sinks” in ocean and land ecosystems but this may become less effective in future

GREENHOUSE GAS WARMING EFFECT

Carbon dioxide
CO2 accounts for 66% of radiative forcing

Nitrous oxide: 7% of heating effect 
332 parts per billion (ppb)

Methane: Remains in atmosphere for 10 years, 16% of heating effect 
1,889 ppb

Other
11% 


ATMOSPHERIC CONCENTRATION OF GREENHOUSE GASES

1985: CO2 345 ppm 
N2O 305.7 ppb 
CH4 1,656.4 ppb

2020: CO2 413.2 parts per million

Atmospheric concentration of CO2 varies seasonally, reflecting balance between emissions from human activities and natural sources, and sinks in biosphere and ocean

Monthly mean

420 
380 
340 
300 

Pre-industrial CO2 ~280ppm
1985 1990 1995 2000 2005 2010 2015 2020 

Around 30% of CO2 from human activity is dissolved into oceans, increasing
acidity of water. Since 1750, acidity of ocean surface has risen by 30%


Sources: World Meteorological Organization, NOAA 
Picture: Getty Images 
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