https://link.springer.com/article/10.1007/s41748-020-00182-6
Antipyretic Medication for a Feverish Planet Markus Stoffel, David B. Stephenson & Jim M. Haywood Earth Systems and Environment (2020)Cite this article 41 Accesses Metricsdetails As the coronavirus pandemic continues to unfold at a staggering pace, CO2 emissions are in for a sharp, if temporary, decline estimated at 7% of the 2019 annual emissions (Le Quéré et al. 2020; Carbon Brief 2020; Forster et al. 2020). Even if this reduction is substantial, it will not suffice to reach the 1.5 °C global temperature target of the 2015 Paris Conference of Parties Agreement (COP, Brown et al. 2019), as a reduction by 7.6% would be needed every year from today to reach net-zero emissions by 2050 (Sachs et al. 2016). Therefore, once the pandemic and ensuing economic lethargy are over, societies will need to make a crucial choice on how to reach the climate goals defined at the COP. Global emissions could resume if nations decided to lean heavily on fossil energy sources to rebuild their economies (Henry et al. 2020; Ou et al. 2020). Under different leadership, strong governmental support for clean energy could tilt major economies towards a greener, more climate-friendly direction (Barbier 2020; Carbon Brief 2020; Rosenbloom and Markard 2020; Andrijevic et al. 2020). Back in 1992, the Intergovernmental Panel on Climate Change (IPCC) forecast carbon dioxide (CO2) concentrations under their ‘IS92a best guess’ scenario (Nakicenovic et al. 2003). These predictions have proved remarkably accurate; an analysis of the mean CO2 concentrations over the past thirty years from the two models available at that time (for details see IPCC 2020) indicates that they are never in error by more than 1.5 ppmv when compared to CO2 observations (NOAA 2020). CO2 concentrations are currently increasing at a rate of around 0.5% per annum; if this continues (as they have for the last 50 years; Showstack 2013), atmospheric concentrations will rise from around 411 ppmv at current levels (their highest for the last 3 million years) to 611 ppmv by 2100 (i.e. 411 ppmv × 0.5% annual increase × 80 years). The IS92a scenario, that has proved so accurate over the last thirty years, suggests an even more pessimistic 713 ppmv (Houghton et al. 1995; IPCC 2020). Given the remarkable validation and future projections of CO2 concentrations, humanity cannot say that they have not been warned of the impact that their activities are having. The scientific consensus is that, given current mitigation efforts, the Paris Agreement target of limiting Global Mean Surface Temperature (GMST) warming to 1.5 °C (or even 2 °C; Masson-Delmotte et al. 2018) above pre-industrial values will be missed. Even if global warming continues to increase at the current rate of around 0.2 °C per decade, which is below the climate projection levels, the 1.5 °C threshold will be exceeded by 2040–50 (Masson-Delmotte et al. 2018). The above facts unfortunately lead to the conclusion that some governments—rather than reducing emissions drastically—may soon start to consider implementing the unpalatable option of solar radiation management geoengineering (Parson 2017; Schubert 2019). Although it may be a foul-tasting medicine, it is considered to provide considerable relief from the ever-increasing catalogue of damaging extreme events (Jones et al. 2018; Irvine et al. 2019; Irvine and Keith 2020). -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/CAJ3C-07UjJqgvqqXwbb3MmFhHYAAK%3D%3DXZsZrWtXGsjKe7TrZjQ%40mail.gmail.com.
