Should the government regulate greenhouse gas as a pollutant? As the Supreme Court takes on one such case, Amanda Leigh Haag finds out who’s suing whom.

What is happening?

The problem of climate change just landed squarely on the desk of the US Supreme Court. Twelve states, led by Massachusetts, plus a handful of cities and non-profit organizations are confronting the Environmental Protection Agency (EPA) on its failure to regulate CO2 emissions from motor vehicles.

Read the briefing here.