The temporary greenhouse gas emission reductions during the COVID-19 lockdowns have done little to slow down the increase in atmospheric GHGs, and the world has a nearly one-in-four chance of temporarily hitting 1.5°C average global warming in the next five years, according to the new United in Science report issued this week by the United Nations, the World Meteorological Organization, and other global science groups.
“The probability of 1.5°C is growing year by year,” said  WMO Secretary-General Petteri Taalas. “It’s very likely to happen in the next decade if we don’t change our behaviour.”
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“Never before has it been so clear that we need long-term, inclusive, clean transitions to tackle the climate crisis and achieve sustainable development,” added UN Secretary General António Guterres in a foreword to the report. “We need science, solidarity, and solutions.”
The study “shows that global lockdowns had a significant and immediate impact on emissions of greenhouse gases, with daily levels in April 2020 falling by 17% compared with 2019,” the British Broadcasting Corporation reports . “But this steep drop hasn’t been maintained. As the world returned to work, emissions rose and by June were within 5% of the previous year,” leading experts to predict a drop of just 4 to 7% for 2020.
And “while emissions can tell us what is happening on the ground, it is the concentrations of these gases in the atmosphere that makes all the difference for global temperatures,” the BBC adds. From that broader perspective, “the period from 2016 to 2020 will likely be the warmest five years on record, the study finds,” and “the authors say ‘irreversible’ climate change impacts are increasing.”
With observatories at Mauna Loa, Hawaii and Cape Grim, Tanzania, both tracking increases in atmospheric CO2 of three parts per million between July 2019 and July 2020, “greenhouse gas concentrations—which are already at their highest levels in three million years—have continued to rise,” Taalas said. “Meanwhile, large swathes of Siberia  have seen a prolonged and remarkable heat wave  during the first half of 2020, which would have been very unlikely without anthropogenic climate change.”
The report points to sea levels rising by 4.8 millimetres per year between 2016 and 2020, Arctic sea ice extent  declining 13% per decade, and unprecedented wildfires in the Amazon , the Arctic , and Australia .
Stanford University climate scientist Noah Diffenbaugh said warming that has already taken place has “increased the odds of extreme events that are unprecedented in our historical experience,” The Associated Press reports. It has increased the odds of record-setting extreme heat across 80% of the globe and “doubled or even tripled the odds over the region of California and the western U.S.  that has experienced record-setting heat in recent weeks.”