The rise in the presence of carbon dioxide, methane and nitrous oxide in the air is showing no signs of a letdown, accelerating global warming, according to the World Meteorological Organization.
Just before the start of the 2021 United Nations Climate Change Conference COP26 in Glasgow, the World Meteorological Organization (WMO) warned the effect of the coronavirus pandemic on the concentrations of heat-trapping greenhouse gases in the atmosphere was negligible. There was only a temporary, 5.6% decline in new emissions last year, but carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) kept building up and the overall volume reached another record.
Furthermore, the annual rate of increase was above the 2011-2020 average and the trend continued from there. As long as emissions continue, global temperature will continue to rise, scientists warned.
The volume of greenhouse gas emissions dropped 5.6% last year due to the pandemic impact, but given that they remain in the atmosphere for a long time, concentrations kept building up
Given the long life of CO2, the temperature level already observed will persist for several decades even if emissions are rapidly reduced to net zero. It means more weather extremes including intense heat and rainfall, ice melt, sea-level rise and ocean acidification, accompanied by far-reaching socioeconomic impacts.
Ability of oceans, land ecosystems to absorb CO2 may be weakening
Roughly half of the CO2 emitted by human activities remains in the atmosphere. The other half is taken up by oceans and land ecosystems. WMO flagged concern that the ability of land ecosystems and oceans to act as so-called sinks may become less effective in the future, citing factors like droughts and wildfires.
Such changes are already happening, the organization said and pointed to the example of the transition of the part of Amazonia from a carbon sink to a carbon source.
The warming effect has been strengthening, mostly due to the rise in the presence of CO2 in the atmosphere
Carbon dioxide accounts for 66% of the warming effect, mainly because of fossil fuel combustion and cement production. The concentration of carbon dioxide, the most important greenhouse gas, reached 413.2 parts per million in 2020 (it breached the 400 milestone in 2015) and is 149% of the pre-industrial level.
Methane is at 262% and nitrous oxide is at 123% of the levels in 1750, when human activities started disrupting Earth’s natural equilibrium, the report shows.
From 1990 to 2020, radiative forcing – the warming effect – increased by 47%, with CO2 accounting for about 80% of the rise.
Taalas: Global warming exceeding Paris Agreement goals
“The Greenhouse Gas Bulletin contains a stark, scientific message for climate change negotiators at COP26. 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 to 2 degrees Celsius above pre-industrial levels,” WMO’s Secretary-General Petteri Taalas said and stressed the impact is huge. “We are way off track.”
CO2 remains in the atmosphere for centuries and in the ocean for even longer, the official noted. The last time the Earth experienced a comparable concentration was three to five million years ago, when the temperature was two to three degrees higher and sea level was 10-20 meters higher than now.
Taalas expressed hope that COP26 would bring “a dramatic increase in commitments” by countries to reach carbon neutrality. “We need to revisit our industrial, energy and transport systems and whole way of life,” he said.