In this article, Met Office Research Fellow Chris Jones discusses the study and what it tells us about limiting global temperature rise.

The COVID-19 pandemic has had a massive impact on our lives, and how we go about day-to-day business. It has directly affected millions of people and put our infrastructure under huge pressure. In this new study we look to see if the changes to our daily lives over the last 12 months have had an effect on the climate. On a global scale, the new study by Jones et al. (2021) (which is also the subject of a Research Spotlight in EOS) finds very little changes are detectable, but the way that we rebuild our economies does offer an unprecedented opportunity to “build back better” and shows potential pathways to meet long-term climate goals.

Many nations, including the UK, responded to the COVID-19 pandemic by restricting travel and other activities during 2020, and into 2021. This caused a temporary reduction in global greenhouse gas emissions and local air pollution.

Empty roads in the UK during the COVID-19 pandemic

Atmospheric concentrations of greenhouse gases have been increasing since the mid-1800s. Once in the atmosphere, these gases form a blanket around the planet trapping heat from the sun and increasing global temperatures. Aerosols, which are tiny particles suspended in the atmosphere, can also affect the Earth’s climate. Pollution from cars and factories is a major source of man-made aerosols but they can also be produced naturally. Aerosols play a key role in Earth’s energy balance through influencing the amount of energy from the sun that is either absorbed in the atmosphere or reflected back into space.  

To see if the temporary reduction in greenhouse gases and aerosol pollutants during the pandemic had any effect on our climate, we looked at results from 12 Earth system models to see how they responded to these emissions reductions. To assemble these results, a huge international research effort was coordinated at very short notice, involving 50 scientists from 30 different research organizations around the world. These research groups ran 12 climate models and performed over 300 experiments to assess the implications of 2020’s unusual emissions.