To keep climate change within the limits to which we can reasonably adapt, the world must reduce emissions at almost the same rate as it did during the peak of the global COVID-19 pandemic, scientists say.
Key points:
- Relative CO2 emissions fell more between 2019 and 2020 than at any other time in recorded modern history
- Climate scientists say reducing emissions by a similar percentage each year, transforming into a clean energy economy, could keep warming around 1.5 ° C
- The climate emergency must be managed with the same urgency as the pandemic, they warn
Between 2019 and 2020, global carbon dioxide emissions experienced the largest year-on-year fall ever, 6.3%, both during the global financial crisis of 2008 and during the estimated decline after the end. of World War II.
If we could continue this trend every year, we could limit warming to about 1.5 degrees Celsius, according to the international team of scientists, which published its results today in Nature Geoscience.
“This tells you that the massive change we saw in the economy – in this case because we were closing it down – requires an equivalent change in the decarbonization of the world,” said study co-author Pep Canadell of CSIRO.
“Those equivalent units of the economy that are closing [during COVID]these units need to be shifted to the zero carbon economy. “
A comparison of the fall in emissions by sector, on average, between 2019 and 2020. (Photographed by: Nature Geoscience)
While the economy shrank significantly during 2020, it doesn’t have to be that way to reduce global emissions, Dr. Canadell said.
“The economy is like this [intertwined] with fossil fuels, which when the economy collapses, so do emissions, ”he said.
“The big message at home is that we need to decouple fossil fuels from the economy.”
Under the 2015 Paris Agreement, the signatory countries undertook to limit the rise in global temperature this century below 2 ° C and to continue efforts to limit warming to 1.5 ° C. C.
But since then, substantial research has shown a sharp increase in risk as warming exceeds 1.5ºC.
“A lot of new research has come out to show the incredible difference between 1.5 ° C and 2 ° C [and] there has been an evolution within the Paris Agreement that we really need to push for 1.5 ° C, ”Dr Canadell said.
“We are now seeing bigger and stronger expressions of climate change, proving that even 1.5ºC is a lot.”
Transportation and shipping are the most important factors
The researchers were able to create a set of daily emissions data for the year 2020, based on activity data and activity fluctuations for each sector.
They found that the most important factor in reducing emissions was the decline in land transport (cars and goods), which accounted for just under a third of the cut.
Almost a third of the emission reductions were due to lower land transport. (Getty Images)
Reduced emissions from international aviation, industry and energy also had a prominent place.
The initial wave of COVID-19 in the first half of 2020, which led to “orders to stay at home, factory closures, air traffic collapse and supply chain disruptions,” caused the fall higher CO2 production compared to equivalent period in 2019.
During a week in April, when many regions were under strict blockade and industrial and aeronautical activity was limited, it was estimated that 17% less carbon dioxide emissions were pumped into the atmosphere, in compared to the same week last year.
In the second half of 2020, emissions recovered to levels close to 2019, and subsequent waves of COVID and consequent restrictions on activity experienced only minor falls.
Brazil and the United States experienced the largest falls as a proportion of their global carbon dioxide emissions in 2020, 9.7% and 9.5% respectively, while China saw their emissions increase. 0.9%, according to the data.
Researchers suggest that China’s continued growth was due to its relatively short lock-in periods and the rapid recovery of full production capacity.
Australia’s quarterly emissions data for September 2021 (including LULUCF) show that we have not yet recovered pre-COVID emissions.
The importance of the study, according to climate scientist Nerilie Abram of the National University of Australia, is that it shows that the world is able to act collectively to implement change at the scale that the climate emergency demands. .
“It’s a great demonstration that it’s possible to reduce our emissions, we just have to choose the way we’re going to do it,” Professor Abram said.
“It’s not just individuals doing their part to reduce the amount they travel – these kinds of things are not the solutions.
“We need a planned transition through society to implement the necessary changes.”
It’s also important to note that we should see how this type of emission reduction gets worse every year in a row as we move toward net zero, he said.
“It’s a really interesting example that shows you what it means when scientists say we need ambitious and immediate action to [combat climate change]. “
The problem, of course, is that in the economic upturn that followed COVID restrictions, emissions have shifted back north, Dr. Canadell said.
“We missed an opportunity and made decisions that weren’t the best for a green recovery.”
However, Dr Canadell said he saw some hope that many countries would remain below 2019 levels.
“Countries where emissions were falling [prior to COVID-19]including the United States and Australia, we are all below where we were in 2019, ”he said.
However, this will not continue without a large-scale change in infrastructure.
“If we don’t make structural changes, we’ll get back to where we were before,” Dr. Canadell said.
“Everyone is grateful that the magnitude of the change in 2020 was huge.
“An equivalent amount of change is needed to get on the road [1.5C]. “
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