Evidence presented to SBSTA by the Global Carbon Project suggests that the COVID-19 global lockdown may result in a 3-months average of 8% fossil fuel emissions reduction and a peak drop of 17%. This may lead to 4-7 per cent drop in emissions over 2020 (dependent on when lockdown restrictions will be eased). This is much larger than the decrease during the 2008 financial crisis (which subsequently led to a rise in emissions of 6% during the recovery period).
“A reduction of emissions in the order of 4-7% globally does not mean that CO2 in the atmosphere will go down, in fact the CO2 will continue to accumulate and the level will just increase a little less than without this reduction,” according to the presentation from WMO. “Discerning the change will be difficult because the superimposed and larger natural variability.”
“Only when the net emission of CO2 comes close to zero, will the net uptake by ecosystems and ocean start to slightly reduce the CO2 levels in the atmosphere. Even then most of the CO2 already added to the atmosphere will remain there for several centuries and take part in the warming of our climate,” said the WMO paper presented by Oksana Tarasova, Head of the Atmospheric Environment Research Division.
Concentrations of greenhouse gases in the atmosphere continue to increase
- Long-term observations coordinated by the WMO demonstrated substantial interannual variability in the concentration annual growth rate that was largely driven by the natural processes (biosphere).
- The separation between natural variability and the one influence by lock-down measures will require datasets over longer time and sophisticated model analysis (helped also by use of isotope measurements).
- The most substantial impact of the shutdown emission reductions on atmospheric GHG concentrations has been observed in urban areas.
- Continued long-term observations under different conditions combined with comprehensive analysis can serve as a guiding tool to see where we go through the economic recovery process and can guide the corrective actions.
Full WMO article here.