Climate at a Glance: COVID-19’s Impact on CO2 Levels

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Key Takeaways:

  • The global economy shrank as a consequence of the lockdowns instituted in response to the COVID-19 pandemic.
  • Despite crashing economies and large cutbacks in travel, industry, and energy generation, climate scientists have yet to find a substantial decline in atmospheric CO2 levels.
  • The lack of a strong reduction in atmospheric CO2 connected to the energy-use decline linked to the COVID-19 pandemic suggests that climate activists’ calls for global energy use reductions would be ineffective in limiting atmospheric CO2 levels. These policies would, however, cause significant economic harm.

Figure 1. Atmospheric CO2 Concentrations

Short Summary:

Governments’ response to the COVID-19 pandemic caused a worldwide reduction in economic activity, as businesses closed, airlines canceled flights, energy production and consumption fell, and people sheltered in their homes.1 However, some climate activists celebrated the economic shutdowns, arguing that they created the largest-ever drops in global CO2 emissions.2

Climate activists expected this economic downtown to result in reduced energy use and fewer CO2 emissions globally, which did occur. China’s CO2 emissions declined by 40 percent. U.S. energy-related CO2 emissions also dropped significantly in 2020. However, the global decline in human emissions did not cause a decline or pause in atmospheric carbon dioxide concentrations.3,4,5

University of Alabama climate scientist Dr. Roy Spencer studied the effect of the pandemic lockdowns on atmospheric CO2 concentrations and found very little, if any, correlation.6 Spencer conducted his analysis by removing from his data the effects of the large CO2 cycle that occurs during seasonalplant photosynthesis processes, as well as the average effects from El Nino and La Nina events, which change the rate of ocean outgassing of CO2. The results showed that there was no substantial downtown in global atmospheric CO2 levels, despite reduced CO2 emissions.6,7,8,9 (See Figure 1.)

Figure 1. Using a simple method for removing the large seasonal cycle from the Mauna Loa CO2
data, as well as the average effects from El Nino and La Nina events, Spencer analyzed atmospheric

CO2 concentrations during the height of the COVID-19 lockdowns and found there was no obvious
downturn in global CO2 levels. It is worth noting that USA Today conducted a fact check on this issue
and found the same result.9 Source: Roy Spencer, “March 2020 CO2 Levels at Mauna Loa Show
no Obvious Effect from Global Economic Downturn,”, April 7, 2020, https://www.

NOAA’s Earth System Research Laboratories also studied the issue and concluded, “That drop in emissions needs to be large enough to stand out from natural CO2 variability caused by how plants and soils respond to seasonal and annual variations of temperature, humidity, soil moisture, etc. These natural variations are large, and so far, the ‘missing’ emissions do not stand out.”10

Clearly, there is no indication that the forced reductions in economic activity and human CO2 emissions had any effect on global CO2 levels, suggesting that natural forces, such as ocean outgassing of CO2, overwhelmed humans’ contributions.

This further suggests that calls from climate activists to reduce fossil fuel use, automobile use, airline travel, beef consumption, etc., would likely have little or no impact on atmospheric CO2 concentrations, unless imposed dramatically and over the long term. Of course, that would undoubtedly be accompanied by an equivalent long-term reversal in economic progress and living standards.


  1. Josh Zumbrun, “Coronavirus-Afflicted Global Economy Is Almost Certainly in
    Recession,” The Wall Street Journal, April 14, 2020,
  2. Tobias Hoonhout, “Dem Rep. Told Colleagues Coronavirus Bill Is ‘Tremendous
    Opportunity to Restructure Things to Fit Our Vision,’” National Review, March 23,
  3. Lauren Sommer, “Why China’s Air Has Been Cleaner During the Coronavirus
    Outbreak,” National Public Radio, March 4, 2020,
  4. U.S. Energy Information Administration, “Short Term Energy Outlook,” May 2020,
    accessed August 15, 2021,
  5. NASA, “Seasonal Changes in Carbon Dioxide,” Scientific Visualization Studio, May 4,
    2017, accessed August 15, 2021,
  6. Roy Spencer, “Is the COVID-19 Economic Downturn Affecting Atmospheric CO2?
    Mauna Loa Data Say, Not Yet,”, March 22, 2020, https://www.
  7. Roy Spencer, “Why the Current Economic Slowdown Won’t Show Up in the
    Atmospheric CO2 Record,”, May 15, 2020, http://www.drroyspencer.
  8. Roy Spencer, “March 2020 CO2 Levels at Mauna Loa Show no Obvious Effect from
    Global Economic Downturn,”, April 7, 2020, https://www.
  9. Matthew Brown, “Fact check: The Coronavirus Pandemic Isn’t Slowing Climate
    Change,” USA Today, May 11, 2020,
  10. National Oceanic and Atmospheric Administration, “Can We See a Change in the
    CO2 Record Because of COVID-19?,” NOAA Earth System Research Laboratories, May

Climate At A Glance is a Project of The Heartland Institute