According to the latest figures published by the Global Carbon Project (GCP), the current coronavirus pandemic has led to a significant reduction in global CO2 emissions. The GCP is an international collaboration of climate researchers, which includes LMU geographers Julia Pongratz, Selma Bultan and Kerstin Hartung as contributors. The group monitors both the amounts of greenhouse gases released into Earth‘s atmosphere and the quantities absorbed by the world’s oceans and sequestered in vegetation on land.
The latest report issued by the GCP shows that, 5 years after the conclusion of the Paris Agreement, the rate of increase in global CO2 emissions has slowed. In the decade from 2010 to 2019, CO2 emissions from fossil sources decreased significantly in 24 countries whose economies had grown over the same period. This result suggests that policies intended to mitigate climate change may be having an effect. Over the course of this year – in part owing to the measures introduced in response to the coronavirus pandemic – global emissions of fossil carbon are estimated to have fallen to 34 billion tons (34 Gt CO2). This figure represents a decrease of some 2.4 Gt from the previous year. This is a considerably larger drop than previous dips in the emission record for the years 1981 and 2009 (0.5 Gt), 1992 (0.7 Gt) and 1945 (0.9 Gt). In order to achieve the goals set out in the Paris Agreement, CO2 emissions must fall by between 1 and 2 Gt annually between now and 2030.
The decrease was particularly notable in the USA (-12%) and in member states of the EU (-11%). “In both cases, reductions in the use of coal were complemented by the effects of the restrictions imposed in response to the coronavirus pandemic,” says Pongratz. “In 2019, the rate of increase in CO2 emissions was slower than in previous years. As a consequence of the pandemic, emissions have now fallen significantly. This makes 2020 a crucial year, but whether it marks the start of a trend strongly depends on how the measures taken to stimulate the economy unfold around the world. We are already seeing signs that the emission rate is climbing back toward the level observed for 2019.”
The transport sector accounts for most of the fall
Most of the decrease recorded for 2020 can be attributed to a drop in the carbon footprint of the transport sector. In December 2020, emissions due to road and air traffic still were lower by about 10% and 40%, respectively, relative to 2019 values. The authors of the report emphasize that it is not yet possible to assess whether the rate of global emissions will continue to fall in the coming years. Following the decrease in emissions in the aftermath of the global financial crisis in 2008, emissions rebounded a massive 5% in 2010, as the global economy recovered. The fear is that this could happen also in 2021.
Overall, total emissions of CO2 – from fossil sources and land use – for 2020 are estimated to be on the order of 39 Gt, which approximately corresponds to the value recorded for the year 2012. This caused the CO2 concentration of the atmosphere to continue rising, and the average concentration for the current year is expected to set a new record of 412 ppm (parts per million). This corresponds to a rise of 48% relative to the pre-industrial level. The authors of the new report point out that the atmospheric CO2 level, and consequently the world’s climate, will only stabilize when global CO2 emissions are near zero. The overall amount of CO2 absorbed by carbon sinks on land and in the oceans continues to rise, and in 2020, they sequestered some 54% of all anthropogenic CO2 emissions.
No significant decrease in emissions from land use change
Julia Pongratz is particularly interested in the impact of changes in land use on the global carbon balance. While unusually high level of emissions from these sources were estimated for 2019 – which were exacerbated by extraordinarily dry conditions in Indonesia and the highest rate of deforestation in the Amazon Basin since 2008 – the value for 2020 is lower again and equivalent to the mean level for the decade as a whole.
“For the first time, we were able to estimate the gross CO2 emissions and removals through land use changes on the global carbon budget in 2020,” Pongratz says. She and her colleagues come to the conclusion that this factor – largely attributable to deforestation – accounts for the release of around 16 Gt of CO2 per year during the past decade. On the other hand, removals of CO2 such as through the abandonment of agricultural lands, over the same period resulted in an estimated increase of nearly 11 Gt in CO2 sequestration capacity. The net balance of +6 Gt for 2020 is similar to the values for previous years. “We have not found a reduction in carbon emissions in this sector yet. Deforestation continues at a rapid pace, especially in tropical regions, and public awareness of the impact of agricultural emissions has been muted owing to the influence of Covid,” Pongratz says. “Effective measures to improve land management could not only curb deforestation, they could also contribute to an increase in CO2 uptake from the atmosphere by allowing for the regrowth of natural vegetation.”
The team of 86 climate researchers from all parts of the world publishes its study in the peer-reviewed journal Earth System Science Data. The Global Carbon Budget 2020 is the 15th edition of the annual update that started in 2006. Besides Julia Pongratz, Selma Bultan und Kerstin Hartung, scientists from 7 other German institutions contributed -- the Alfred-Wegener-Institut (Bremerhaven), the Max Planck Institute for Meteorology (Hamburg), the Max Planck Institute for Biogeochemistry (Jena), the Karlsruhe Institute of Technology, the GEOMAR Helmholtz Centre for Ocean Research (Kiel) and the Leibniz-Institut für Ostseeforschung (Warnemünde).