Global fossil carbon emissions rebound near pre-COVID-19 levels

Fossil CO 2 emissions in 2021 grew an estimated 4.2% (3.5%–4.8%) to 36.2 billion metric tons compared with 2020, pushing global emissions back close to 2019 levels (36.7 Gt CO 2 ).

At the time of peak confinement in a given country, emissions decreased by one quarter (26%) on average (Le Quéré et al. 2020).Daily global fossil CO2 emissions decreased 17% at peak confinement in April of 2020 (compared to 2019), and daily emissions decreased up to 75% in aviation, 50% in road transportation, and 35% in industry (Le Quéré et al. 2020).
Almost half of the decline in total annual fossil CO2 emissions in 2020 was attributable to reductions in transport activity (Le Quéré et al. 2020, Liu et al. 2020).
The economic disruption of COVID-19 in 2020 altered emissions in ways that varied by country, sector, and fuel type and that may have accelerated the transition to renewables.
China was among the few large countries whose emissions increased in 2020 compared with 2019, despite a large but brief drop attributable to COVID-19 (Figure 1).The increase in China's total emissions was attributable primarily to its power and industry sectors, where emissions increased by ~54 and 156 Mt CO2, respectively, in 2020 compared to 2019, according to preliminary estimates (Liu et al. 2020).Most of this increase took place after April 2020 in the more industrialized maritime provinces of China (Zheng et al. 2020).
Almost all other sectors and countries showed substantial reductions in CO2 emissions from 2019 to 2020 (Figure 1) (Friedlingstein et al. 2021).
For fuels globally in 2020, coal use fell 6.2 EJ to 151.4 EJ/yr, a 4% decline compared to consumption in 2019 (Figure 2).Petroleum consumption decreased even more (9.6%) in 2020-an 18.2 EJ drop to 173.7 EJ/yr.Gas consumption fell a modest 2.1% to 137.6 EJ.In contrast, wind, solar, and other renewable sources jumped 10% in 2020 to 31.7 EJ, despite a substantial 25 EJ decline in global energy demand attributable to COVID-19 (Figure 2).
For 2021, we project that global fossil CO 2 emissions compared with 2020 levels will rebound by 4.9% (4.1% to 5.7%) to 36.4±0.3Gt CO 2 , nearly overlapping 2019 emission levels of 36.7 Gt CO 2 (Figure 1) (Friedlingstein et al. 2021).CO 2 emissions in 2021 are expected to rise compared to 2020 in every country and region.Our 2021 fossil CO2 emissions projections are based on energy data for coal, oil and gas for the first 7 to 9 months of the year for China, USA, EU27+UK, and India, and a GDP-based projection for the Rest of the World.Full details are provided in Friedlingstein et al. (2021).
Projected fossil emissions for China in 2021 are 11.1 Gt CO2, an increase of 4.0% (range 2.1% to 5.8%) compared with 2020 emissions and almost 7% higher than in 2019 (Figure 1).In fact, the largest increases across sectors and countries in 2021 compared with 2019 are found in China's power and industrial sectors (385 and 303 Mt CO2, respectively; Figure 3).Projected fossil CO2 emissions for India in 2021 are 2.7 Gt CO2, a substantial rebound of 12.6% (10.7% to 13.6%) compared with 2020, and slightly (~3%) above its 2019 emissions (Figure 1).In contrast, projected fossil CO2 emissions for the United States and European Union in 2021 are expected to remain below 2019 levels, despite substantial increases relative to 2020 of 7.6% (5.3% to 10.0%) and 7.6% (5.6% to 9.5%), respectively, in 2021 (Figure 1).Our 2021 projections reflect long-term background trends of increasing CO2 emissions for India and decreasing CO2 emissions for the United States and European Union.
For China, in contrast, COVID-19 recovery may have sparked growth in CO2 emissions, whereas for the Rest of the World (in aggregate), it may act to dampen the recent growth in emissions (Figure 1).
For fuels in 2021, we project that CO2 emissions from coal use will rebound above 2019 levels to 14.7 Gt CO 2 (Figure 1), primarily because of increased coal use in China (Figure 4), and will remain only slightly (0.8%) below their peak in 2014 (Figure 1).CO 2 emissions from natural gas use in 2021 (7.7 Gt CO 2 ) are also expected to rebound above 2019 levels; of all fossil fuels, gas use has risen steadily for at least sixty years (Figure 2).Only CO 2 emissions from oil remain well below 2019 levels in 2021 at an estimated 11.5 Gt CO 2 (Figures 1 and 2).
The distribution of the 2021 rebound in fossil CO2 emissions is heterogenous across countries and sectors (Figures 1 and 3).Beyond the increases in China's power and industrial sectors in 2021 discussed above, other sectors that have also surpassed 2019 levels include power in India and Brazil (49 and 35 Mt CO 2 higher, respectively), residential emissions in the European Union (22 Mt CO2 higher), and all sectors in Russia other than international aviation (totaling 35 Mt CO2 higher) (Figure 3).These increases are balanced by sustained reductions in many other sectors, primarily international aviation emissions, which are still well below 2019 levels in all major countries (Figure 3).
Rapidly increased market penetration of renewables that displace fossil fuels is critical for limiting climate change in the 1.5° to 2°C range (Figure 2).Although most 1.5°C mitigation scenarios (e.g., van Vuuren et al. 2018) require the substitution to no-or lowcarbon sources for almost all energy infrastructure by 2050, this transition is not currently occurring quickly enough to limit warming to 1.5°C (IPCC 2018).Global gas use is rising particularly quickly.Despite the temporary effects of COVID-19 to suppress energy demand and supply, gas use and its associated CO 2 emissions rose more than 2% a year on average for the five-year period of 2015-2020 (Figures 1 and 2).In consequence, fossil CO 2 emissions associated with gas use over the next few years are likely to surpass 8 Gt CO 2 /yr.The continuing rise in natural gas use is also problematic for climate because the CO2 emissions come with large and poorly constrained additional warming from methane leakage associated with fossil extraction and use (e.g., Hmiel et al. 2020, IEA 2021).Just as for coal and oil, which were also rising quickly prior to COVID-19 (Figures 1 and 2), carbon emissions from global gas use must drop rapidly if global temperatures are to stabilize below increased thresholds of 1.5 or 2 °C (Davis et al. 2019).
Climate change was revealed in many ways in 2021.Average global temperatures for the period 2017 through 2021 are expected to be between 1.1 and 1.3 °C higher than in preindustrial times (WMO 2021).Human-induced climate change is already increasing the frequency and intensity of weather and climate extremes in virtually every region of the globe (IPCC 2021).Moreover, five years after the Paris Agreement, the emissions gap continues to grow: global emissions need to be 15 billion tons CO2e lower (for all greenhouse gases, not just CO2) than current nationally determined contributions (NDCs) for a 2 °C goal, and 32 billion tons CO2e lower for the 1.5 °C goal (WMO 2021).Progress in reducing emissions is occurring, albeit slowly (Le Quéré et al. 2019, 2021, Eskander and Fankhauser 2020).Fossil CO2 emissions significantly decreased in 23 countries during the decade 2010 through 2019; for the 5-year period of 2015 through 2019, fossil CO2 emissions decreased in 64 countries globally (Friedlingstein et al. 2021).
The rapid rebound in global fossil CO 2 emissions in 2021 (returning very close to 2019 levels) is driven primarily by emissions in the power and industry sectors (Figures 3 and   5).Fossil-based investments in economic stimulus packages in post-COVID recovery plans around the world appear to have overwhelmed substantial investments in green infrastructure (Hepburn et al. 2020).The full effect of responses to the COVID-19 pandemic on CO2 emissions is still uncertain, but a further rise in emissions in 2022 cannot be ruled outgiven the surface transport and aviation sectors have not yet fully recovered (Figures 3 and   5).Green investments could still work to alter underlying emissions trends, as many will take years before showing their full effects (Andrijevic et al. 2020).These trends reinforce the need for strong and globally concerted actions to slow fossil-based investments (that continue to push CO 2 emissions up) and to set global emissions on a trajectory consistent with the temperature limits set in the Paris Agreement.

Figure 2 .
Figure 2. Top panel: Annual global energy consumption (EJ) by fuel source from 2000 through 2020 (BP 2021), with average annual growth shown under brackets for the period 2015 through 2020.Bottom panel: Fossil CO 2 emissions by fuel type (coal, oil, and natural gas) plus emissions from cement production and flaring; note that these emissions estimates do not include methane leakage during extraction and use.

Figure 3 .
Figure 3. Fossil CO2 emissions by sector and country for the difference between 2021 and

Figure 4 .Figure 5 .
Figure 4. Annual fossil CO 2 emissions (Gt CO 2 ) in China by fuel type and industry.The projected emissions growth numbers for 2021 (in %) are relative to 2020 emissions.