The Global Carbon Project is a worldwide consortium of researchers who annually document the amount of CO2 that enters the atmosphere and how much of it is sequestered by sinks on land and in the ocean. For 2020, the team recorded the largest reduction in fossil CO2 emissions ever observed. In the wake of action against the coronavirus, global CO2 emissions fell by 5.4 percent from the previous year - about four times more than the reduction caused by the global financial crisis in 2009.1
My research group has been working with the Global Carbon Project for several years. This year, I was particularly curious to see how the world's emissions would unfold. Did countries use the billions of dollars in financial injections not only to lift them out of the Corona crisis, but also to prepare their economies for a carbon-neutral future?
In a newly published report, the Global Carbon Project presents the first projections for 2021. Unfortunately, they are sobering: After the Corona-induced decline in 2020, global emissions this year are likely to shoot back up almost to the record level of 2019.2, 3 However, it is worth taking a detailed look at the drivers and trends among the major emitters: The global decline and rebound in CO2 emissions hides relevant regional and sectoral differences.
Pre-Corona trends continue
Preliminary results show that in 2021, major emitters continue their respective pre-Corona trends: in the U.S. and the EU, CO2 emissions are trending downward; for them, the increase in 2021 is smaller than the decrease in 2020. In contrast, in China and India, emissions are increasing and in 2021 are above the pre-pandemic level of 2019.
Analyses by Carbon Monitor, a platform that estimates emissions virtually in real time, further show that the increase in global emissions in 2021 is fueled primarily by energy production and industry - this with an increased use of coal, whose use rose by almost six percent.4 Supply bottlenecks for natural gas have certainly contributed to the renewed renaissance of this particularly climate-damaging energy source.
Drivers of the decline
While it is still too early to take a differentiated look at the emissions drivers for the current year, the Global Carbon Project has done this for 2020. In the pandemic year, fossil emissions fell by more than 10 percent in the US and EU, and by more than 7 percent in India. In China, growth slowed, but emissions still grew by 1.4 percent.
The main cause of the plummeting CO2 emissions was the declining economic output due to globally imposed measures such as lockdowns to curb the spread of the virus. This is unsurprising, as the growth of the economic output has been the strongest driver of changes in global fossil CO2 emissions for more than 30 years. One bright spot, however, is that the trend toward improved energy efficiency and reduced CO2 intensity of energy production has continued in the pandemic year of 2020. This means that less CO2 is being emitted to achieve the same economic output.
This confirms a development that has been ongoing for more than a decade. Thanks to higher energy efficiency and reduced CO2 intensity, economic output and emissions are becoming increasingly decoupled. This is very encouraging, because this decoupling forms the backbone for the decarbonization of the global economy. It is particularly noteworthy that there are already 27 countries where fossil CO2 emissions have actually fallen over the last decade while the economy has grown. Among them is Switzerland, although it should be noted here that this only applies to the so-called territorial emissions. If the import of "grey" CO2 is taken into account, Switzerland loses its pioneering role.
No help for climate change
This is mainly because it is the total amount of CO2 in the atmosphere that is relevant for climate change. Cumulative emissions are much more important than the emissions of a single year. And in terms of the accumulation of CO2 in the atmosphere, we increased it substantially during 2020 as well - despite the Corona-induced decline in emissions. CO2 concentrations rose by a hefty 2.4 parts per million (ppm) to a new record high of 412 ppm, an increase of more than 18 billion metric tons of CO2. That's a lot, but only about half of the total man-made emissions of about 37 billion metric tons of CO2 in 2020, the other half being removed from the atmosphere by sinks on land and in the ocean.
The sinks continue to work amazingly well
These strong sinks are another bright spot for me. For more than 60 years, the land and oceans have almost consistently absorbed about half of the total man-made emissions, even though they have more than tripled. This means that the sinks have grown in sync, and now also absorb more than three times as much CO2. This is astonishing given how complex and potentially prone to change the underlying processes are, especially with respect to climate change. This threat is supported by latest report from the Intergovernmental Panel on Climate Change (IPCC). We must assume that the sinks will generally decrease in the future with climate change.5 Fortunately, we do not yet see this in the sink estimates to which my group has contributed with model calculations and data analyses.
The residual budget is shrinking fast
Even though the pandemic year 2020 brought the biggest drop in emissions in the last 60 years - more than five percent - the decline is not particularly impressive in relation to the reduction required by the Paris climate targets. To meet the two-degree target, we would need to reduce emissions by at least five percent every year from now on.
Meanwhile, the carbon budgets for the Paris climate goals are shrinking rapidly. As of 2022, the remaining allowed emissions to meet the 1.5-degree target with 67 percent probability is about 325 billion metric tons of CO2. For the two-degree target, the budget is around 1075 billion metric tons. With emissions remaining constant, this would leave less than 10 years for a 1.5-degree warmer world, and less than 30 years for a maximum two degree warmer world.6
Given the long renewal cycles of energy systems, the window for the 1.5-degree target is probably closed by now. Nevertheless, we should make every effort to keep warming as low as possible, because every additional tenth of a degree harms us and our environment more.
The direction is right
Certainly, the resurgent emissions in 2021 are a concern because we missed a real opportunity to accelerate the sustainable transformation of the economy through the Corona bailout. Nevertheless, I am optimistic. The decarbonization of the economy is underway. Renewables have a steep growth curve. Their costs have fallen sharply and they are competitive with fossil fuels in many areas. A great many countries have set themselves longer-term climate targets since Paris.
These are major steps, and their impact should not be underestimated. Clearly, we are moving far too slowly; clearly, we need to massively accelerate decarbonization across all countries and sectors. But the direction is right. That makes me confident that we can still achieve the Paris climate targets.