EPA’s current proposed finding determined six greenhouse gases to be harmful but only covers US mobile sources (CAA Section 202(a) sources). Interesting features of EPA’s ruling are:
The finding of endangerment was influenced by the long-life of these pollutants; current emissions of these pollutants will be in the atmosphere for many centuries no matter what reduction policies are implemented now. Their long-life means we are already committed to global climate change even if we don’t know what that change is going to look like.
US Mobile sources are a huge contributor to global emissions, ranked fourth among eight contributing global sources which are as follows:
1. Total Chinese emissions
2. Total US emissions
3. Total Russian emissions
4. Total Indian emissions
5. US Mobile emissions
6. Total Japanese emissions
7. Total Brazilian emissions
8. Total German emissions
In the US, only electricity generation outpaces mobile sources in contribution of greenhouse gases.
Impacts of global climate change will be most pronounced upon vulnerable populations sectors (low-income and immigrant) and geographic regions (Atlantic and Gulf Coastal regions due to rising sea levels and the arid southwest due to drought).
The EPA’s finding of endangerment and contribution of these greenhouse gases is necessary to get cohesive policies in place to address current observed effects of climate change and prepare for potential abrupt impact events (like the collapse of the West Antarctic Ice Sheet).
[...] EPA’s proposed modification to CAA Section 202 (a) recently stated that the effect of atmospheric greenhouse gases endangers humans through global warming. Global warming increases air and ocean temperatures, melts snow and ice over widespread geographic areas and increases average sea levels, causing various problems directly to human health, and indirectly to institutions and infrastructure. [...]