Atmospheric Greenhouse Gas Emissions Hit Record Levels, Report Warns

The surge in global green­house gas emis­sions in 2021 rep­re­sents a fur­ther threat to inter­na­tional efforts to con­tain Earth’s tem­per­a­ture rise, the World Meteorological Organization (WMO) warned.

According to data pre­sented by the WMO at the COP26 inter­na­tional cli­mate sum­mit, emis­sions have now reached new records, top­ping the alarm­ing data reported in the pre­vi­ous year.

“At the cur­rent rate of increase in green­house gas con­cen­tra­tions, we will see a tem­per­a­ture increase by the end of this cen­tury far in excess of the Paris Agreement tar­gets of 1.5 ºC to 2 ºC above pre-indus­trial lev­els,” said Petteri Taalas, the sec­re­tary-gen­eral of WMO. ​“We are way off track.”

Carbon diox­ide, methane and nitrous diox­ide are among the most rel­e­vant green­house gas emit­ted as a result of human-related activ­i­ties.

“The increase in car­bon diox­ide from 2019 to 2020 was slightly lower than that observed from 2018 to 2019 but higher than the aver­age annual growth rate over the last decade,” the WMO wrote in a recent report.

“This is despite the approx­i­mately 5.6 per­cent drop in fos­sil fuel car­bon diox­ide emis­sions in 2020 due to restric­tions related to the Covid-19 pan­demic,” they added.

Emissions of both nitrous diox­ide and methane in 2020 were higher than the pre­vi­ous year and both were above the aver­age emis­sions recorded in the pre­vi­ous decade. In 2021, the emis­sions of both gases con­tinue to grow.

The impact of the spe­cific gases on global warm­ing varies con­sid­er­ably depend­ing on their con­cen­tra­tion and dura­bil­ity in the atmos­phere.

“Each of these gases can remain in the atmos­phere for dif­fer­ent amounts of time, rang­ing from a few years to thou­sands of years,” the U.S. Environmental Protection Agency wrote in a note.

“All of these gases remain in the atmos­phere long enough to become well mixed, mean­ing that the amount that is mea­sured in the atmos­phere is roughly the same all over the world, regard­less of the source of the emis­sions,” they added.

According to WMO, car­bon diox­ide is the most dan­ger­ous of all green­house gases due to its long-last­ing dura­bil­ity in the atmos­phere.

Boosted by fos­sil fuel com­bus­tion and cement pro­duc­tion, the WMO said car­bon diox­ide is respon­si­ble for at least 66 per­cent of the global warm­ing effect. The agency esti­mates that in 2020, this gas con­cen­tra­tion in the atmos­phere had risen to 149 per­cent above pre-indus­trial lev­els. Methane was up 262 per­cent and nitrous oxide 123 per­cent.

While methane and nitrous oxide are pro­duced by sev­eral dif­fer­ent human-related activ­i­ties, live­stock and fer­til­izer pro­duc­tion are among the main sources of both green­house gases.

“Global human-induced nitrous oxide emis­sions, which are dom­i­nated by nitro­gen addi­tions to crop­lands, increased by 30 per­cent over the past four decades,” the WHO said. ​“Agriculture, owing to the use of nitro­gen fer­til­iz­ers and manure, con­tributes 70 per­cent of all anthro­pogenic nitrous oxide emis­sions. This increase was mainly respon­si­ble for the growth in the atmos­pheric bur­den of nitrous oxide.”

“As long as emis­sions con­tinue, global tem­per­a­ture will con­tinue to rise,” they added. ​“Given the long life of car­bon diox­ide, the tem­per­a­ture level already observed will per­sist for sev­eral decades even if emis­sions are rapidly reduced to net zero.”

“Alongside ris­ing tem­per­a­tures, this means more weather extremes includ­ing intense heat and rain­fall, ice melt, sea-level rise and ocean acid­i­fi­ca­tion, accom­pa­nied by far-reach­ing socioe­co­nomic impacts,” they added.

Taalas said that the ​“last time the Earth expe­ri­enced a com­pa­ra­ble con­cen­tra­tion of car­bon diox­ide was three to five mil­lion years ago when the tem­per­a­ture was 2 ºC or 3 °C warmer and sea level was 10 or 20 meters higher than now.”

At the time, Taalas con­cluded, ​“there weren’t 7.8 bil­lion peo­ple [on the planet].”

• World Meteorological Organization
• UN News
• Environmental Portection Agency