Strengthened scientific support for the Endangerment Finding for atmospheric greenhouse gases

Abstract

We assess scientific evidence that has emerged since the U.S. Environmental Protection Agency’s 2009 Endangerment Finding for six well-mixed greenhouse gases and find that this new evidence lends increased support to the conclusion that these gases pose a danger to public health and welfare. Newly available evidence about a wide range of observed and projected impacts strengthens the association between the risk of some of these impacts and anthropogenic climate change, indicates that some impacts or combinations of impacts have the potential to be more severe than previously understood, and identifies substantial risk of additional impacts through processes and pathways not considered in the Endangerment Finding.

Doubling of U.S. Population Exposure to Climate Extremes by 2050

“…There is now clear evidence that these and other forms of climate‐related threats to the economy, human health, and ecosystems are on the rise (Duffy et al, 2019). For example, the U.S. has witnessed a substantial increase in billion‐dollar disasters during the past five years (2015 to 2019: 13.8 events per year) compared to the long‐term average (1980 to 2019: 6.5 events per year).…”

Untangling global change impacts on hydrological processes: Resisting climatization

“…Noting that the countries most responsible for loading Earth's atmosphere with greenhouse gases may differ from those that bear the brunt of climate change impacts, the hydrological science literature may play a role in attribution of observed phenomena as adverse effects of climate change, as a consequence of which the impacted countries may seek aid from those countries chiefly responsible for emissions or global organizations that fund climate change adaptation (Grant, Tamason, & Jensen, ). Finally, accurate climate change attribution research serves as the basis for government determination as to the threat posed to its citizens by climate change, as in the Endangerment Finding by the U.S. Environmental Protection Agency (Duffy et al, ), and the consequent need for a government response. Although it is important not to downplay the already observed and predicted future effects of anthropogenic climate change, these widespread broader societal impacts motivate accurate attribution (Van Loon, Stahl, et al, ) and clear communication of the relative importance of global change impacts on hydrological processes.…”

Chronic Mental Health Impacts of Climate Change Extremes: A Case Study of the Largest Californian Wild Fire

“…Natural disasters, such as oods, cyclones and droughts, are predicted to increase as a consequence of climate change (1). The annual western forest-re area in the US increased by ~ 1000% from 1984 to 2017 (2), and since the 1970s to 2018, particularly California has witnessed an eight-fold increase in the areal extent of res (3,4). During the same period the state has warmed by 1.4ºC (about 50% greater than global warming estimates) largely due to anthropogenic sources (2).…”

“…The annual western forest-re area in the US increased by ~ 1000% from 1984 to 2017 (2), and since the 1970s to 2018, particularly California has witnessed an eight-fold increase in the areal extent of res (3,4). During the same period the state has warmed by 1.4ºC (about 50% greater than global warming estimates) largely due to anthropogenic sources (2). In 2017-2018 alone, there have been approximately 16,000 wild res reported in this state, with 2 million acres of land burned, resulting in 13.7 billion USD in costs of damages, and ~ 250 reported injuries, 25% of which have resulted in death (5,6).…”