As a result of the global COVID-19 (Coronavirus Disease 2019) pandemic, there have been huge reductions in economic activity, with the lockdowns imposed to reduce the spread of the disease causing widespread reductions in transport and aviation emissions. This has resulted in a reduction in the emissions of many short-lived climate forcers (SLCF) and in this study, we have quantified using a chemistry-climate model how these changes in SLCF are likely to impact on atmospheric composition and the radiative balance of the atmosphere using a set of idealised experiments. In spite of large changes in nitrogen dioxide and aerosol optical depth (both improvements for an air quality perspective), we find that there is a very small change in the radiative balance of the atmosphere and neglecting any aerosol-cloud interactions this small change results in a negative forcing which would act to cool the planet. However, these effects are all likely to be very short-lived depending on what happens to emissions following the return to the new normal.