In 2020, civilization emitted an estimated 34 billion tonnes (or 37.5 billion tons) of heat-trapping carbon dioxide into the atmosphere, according to an annual analysis released Thursday by the Global Carbon Project, an organization that annually compiles worldwide carbon emissions. Because the pandemic temporarily depressed economic activity and slowed travel while luridly killing well over 1.5 million people (with over 290,000 deaths in the U.S. alone as of Dec. 10), global carbon dioxide emissions were seven percent lower than they were in 2019.
But, critically, the number that global warming cares about — the amount of CO2 in the atmosphere — still increased and hit a record high in 2020. That is to say, carbon emissions from human activity were less this year, but were still a hell of a lot.
Put another way, the CO2 amassing in our atmosphere is like a wealthy person’s burgeoning bank account. 2020’s 34 billion tonnes were another sizable deposit.
The seven percent drop in emissions this year, as a result of the pandemic, was the largest fall since World War II. But much of this drop is almost certainly temporary as economies strive to recover.
“Emissions will most likely rebound in 2021,” Corinne Le Quéré, a research professor of climate change science at the University of East Anglia who worked on the 2020 emissions research, said at Future Earth’s Global Carbon Project press conference on Thursday.
Exactly how much emissions rebound in 2021 is still uncertain, Le Quéré noted, as this depends on how quickly economies recover and how they recover (if many people adopt working from home, for example, transportation emissions would fall). China, the top emitter of CO2 (the U.S. is second), is already close to returning to its prodigious 2019 emission levels, the report found.
Overall, the UN expects the temporary pandemic emissions drop to have a “negligible” impact on the climate, resulting in just a 0.01C reduction in warming by 2050.
Not all the carbon humanity emits stays in the atmosphere — but much of it does. Both the land and ocean act as potent “carbon sinks,” meaning they absorb CO2 from the atmosphere (that’s why the oceans are acidifying, to the detriment of corals and other marine life). In 2020, Global Carbon Project researchers estimated the oceans soaked up some nine billion tonnes of CO2 while land absorbed around 13 billion tonnes. Ultimately, when accounting for CO2 also released from land (largely from deforestation), some 19 billion tonnes will be left.
Each year, as billions of tonnes are added to the atmospheric CO2 bank account, the planet continues to warm. Nineteen of the last 20 years are the warmest on record. Meanwhile, atmospheric CO2 levels haven’t been this high in — though more likely . Yet to curb Earth’s relentless warming trend, CO2 emissions must fall, dramatically.
“In order to stabilize the climate, CO2 emissions need to be reduced, eventually down to zero,” Pierre Friedlingstein, chair in Mathematical Modelling of the Climate System at the University of Exeter, said at The Carbon Project presentation.
Honestly mystified by the notion that generating energy by setting fire to ancient dead stuff represents some pinnacle of human achievement and creativity
— Kate Marvel (@DrKateMarvel) December 10, 2020
To put the world on the road to stabilizing the climate at a highly ambitious 2 degrees Celsius, or 3.6 Fahrenheit, above pre-Industrial temperatures (which would limit the worst impacts of climate change), emissions need to fall each year for the next decade by 1 or 2 billion tonnes annually, Friedlingstein noted.
Can it happen?
Climate policy experts have outlined a path forward. It will, however, take unprecedented efforts on behalf of countries to slash carbon emissions in the coming decade and beyond. The opportunity lies in a green recovery from an economically devastating pandemic.
“We need to make some change,” Anne Olhoff, a UN climate policy expert, told Mashable on Wednesday. “The openings for doing so are enormous investments going into recovery.”
The rates of carbon emission increases have indeed slowed over the last decade as natural gas replaces coal, the dirtiest fossil fuel, in major economies like the U.S. But truly curbing carbon emissions will need a potent kick from the government. “Government actions to stimulate the economy at the end of the COVID-19 pandemic can also help keep emissions down and tackle climate change,” Le Quéré said. “Incentives that help accelerate the deployment of electric cars and renewable energy, and support walking and cycling in cities are particularly timely given the deep perturbations observed in the transport sector this year.”
As the years pass, the consequences of a heating planet become increasingly stark. A warmer planet exacerbates drought, amplifies storms and flooding, stokes extreme wildfires, destabilized Antarctica’s Florida-sized Thwaites Glacier, and is driving the spread of vector-borne disease. It’s going to get warmer. How much so, is the question.