A dramatic drop in greenhouse gases and air pollutant emissions during the Covid-19 lockdown will have a small impact on global warming, scientists say. Recent analyses show that by 2030, global temperatures will be only 0.01 degrees lower than expected.
But the authors point out that nature’s recovery could have a significant impact on long-term forecasts. A strong green impulse could keep the temperature rise to 1.5 degrees by the middle of this century, the BBC writes on Friday.
Earlier studies also indicated changes in greenhouse gas emissions after the transport system stalled as part of measures against the coronavirus pandemic. Global daily carbon emissions fell 17 percent at the height of the crisis.
The new study builds on that data using results from Google and Apple on global population movements. The team led by prof. Piers Forster of the University of Leeds calculated that gases and air pollutants changed from February to June 2020 in 123 countries.
Experts found that they fell the most in April. Carbon dioxide, nitrogen oxides and other emissions are less than ten to 30 percent globally, mainly due to traffic shutdowns.
But new research shows that the fall in some greenhouse gases has offset the effect of others in terms of global warming.
Nitrogen oxides from transport usually heat the atmosphere. They have fallen 30 percent, as has sulphur dioxide, which is mostly formed by burning coal.
The release of this gas helps to form an aerosol that reflects sunlight back into space and thus cools the planet. This reversal of effects, combined with temporary restrictions due to the pandemic, means that the effect on global warming by 2030 will hardly be felt, scientists point out.
"While temporary changes are helping, carbon dioxide emissions need to be reduced permanently to reflect global warming," Forster said.