Impact of Covid19 on Climate

1:30 to 2:00 pm James Weber: Minimal climate impacts from short lived climate forces following emission reductions related to the COVID ‐19 pandemic

2:00 to 2:30 pm Sanna Markkanen: Maximising the benefits: Economic, employment and emissions impacts of green recovery stimulus in Europe

2:30 to 3:00 pm Paul Young: Lockdown and future pathways to sustainability: Learning and doing from broad perspectives

Abstracts

James Weber

Title: Minimal climate impacts from short lived climate forces following emission reductions related to the COVID ‐19 pandemic

We present an assessment of the impacts on atmospheric composition and radiative forcing of short‐lived pollutants following a worldwide decrease in anthropogenic activity and emissions comparable to what has occurred in response to the COVID ‐19 pandemic, using the global composition‐climate model United Kingdom Chemistry and Aerosols Model (UKCA). Emission changes reduce tropospheric hydroxyl radical and ozone burdens, increasing methane lifetime. Reduced SO2 emissions and oxidizing capacity lead to a decrease in sulfate aerosol and increase in aerosol size, with accompanying reductions to cloud droplet concentration. However, large reductions in black carbon emissions increase aerosol albedo. Overall, the changes in ozone and aerosol direct effects (neglecting aerosol‐cloud interactions which were statistically insignificant but whose response warrants future investigation) yield a radiative forcing of −33 to −78mWm−2. Upon cessation of emission reductions, the short‐lived climate forcers rapidly return to pre‐COVID levels; meaning, these changes are unlikely to have lasting impacts on climate assuming emissions return to pre‐intervention levels.

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Sanna Markkanen

Title: Maximising the benefits: Economic, employment and emissions impacts of green recovery stimulus in Europe

Abstracts: This report contributes to the growing evidence base of what green recovery policies can achieve in Europe by drawing on Cambridge Econometrics’ E3ME modelling results carried out for the We Mean Business Coalition publication, Assessment of Green Recovery Plans after COVID -19. The CLG Europe technical report presents an overall view of the EU, the UK and specific EU economies including Poland, Germany and Spain.

The modelling results show the Green Recovery plan as consistently more favourable than more traditional option of cutting VAT by 5 percent in terms of boosting GDP and employment, as well as contributing to additional reduction in CO2 emissions. At the EU level, the effect of increases over time with significantly better outcomes shown in 2030 if Green Recovery packages are pursued. The modelling also illustrates how countries can achieve maximum impact at a national level, taking into consideration the contextual factors that may restrict the benefits from specific green recovery measures. However, it is also clear from the results that in some countries there will be a need for longer-term support beyond the two-year period that most countries have announced economic stimulus packages for and as modelled in the packages in this report.

The report is accessible online from https://www.corporateleadersgroup.com/reports-evidence-and-insights/maximising-the-benefits

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Paul Young

Title: Lockdown and future pathways to sustainability: Learning and doing from broad perspectives

COVID19 has wrought massive disruption to lives and livelihoods. Through changing our habits and activities, this disruption has left a signature on important atmospheric processes, including air pollution and greenhouse gas emissions. From an atmospheric science point of view, it has created a “natural experiment”, where we can test our understanding of atmospheric chemistry and physics from an abundance of measurements and advanced analyses. I shall review some of this work in terms of air pollution and greenhouse gas emissions, including demonstrating how new data science techniques are becoming an indispensable tool for this research. There have also been broader discussions as to whether the lockdown is a suitable model for a sustainable future, or how we might use this as an opportunity to Build Back Better. Environmental science certainly has important contributions to this discussion, but I will argue that it must recognize its limitations and engage in a broader coalition of expertise and participants if it is to play a useful, legitimate and just role.