A review of the state of the climate crisis in the midst of the COVID-19 pandemic

The atmospheric concentration of well-mixed greenhouse gases has drastically increased since 1850. The prime cause for this increase is anthropogenic activity, particularly the burning of fossil fuels. As a consequence of the changing atmospheric composition, we observe a net positive radiative forcing, which manifests in global warming. The global mean surface temperature has increased since the preindustrial by about 1.0 degrees C. Under the assumption of continued greenhouse gas emissions, climate models project a temperature increase between 3.7 degrees C and 4.8 degrees C until 2100 (compared to the 1850-1900 mean). The assessment reports of the Intergovernmental Panel on Climate Change detail the catastrophic consequences of global warming of such extent for both ecosystems and mankind. As a consequence, the Paris Agreement aims to limit global warming to below 2 degrees C, ideally 1.5 degrees C, when compared to the preindustrial. To achieve this goal, fast and ambitious emission controls are required, reaching net zero emission by 2050 at the latest. Examining the global greenhouse gas emissions of recent decades, it becomes obvious how far away we are at present from reaching this goal. Also, the currently determined national contributions for emission reduction do not suffice to meet the 1.5 degrees C target. Thus, it is of uttermost importance to raise the global ambition in climate protection. The 1.5 degrees C target can still be reached, however, the time to set the required measures will expire within this decade.