And where does climate change fit into all of this?
Doing nothing about greenhouse gas emissions would cost the U.S. billions of dollars and thousands lives.
New rules for oil trains aren't nearly strict enough to prevent disastrous explosions. The most dangerous cars can keep rolling until 2018.
New FEMA guidelines could push states to consider how climate change will affect their communities in order to gain access to funding.
As urban air pollution in China worsens, artists are taking to the streets and social media to document the problem and share their discontent.