Earlier this week, the United Nations Intergovernmental Panel on Climate Change (IPCC) released its first report commissioned under the Paris agreement. Among the report’s startling findings is that the most severe effects of climate change could occur as a result of a 2.7 degree Fahrenheit increase above preindustrial levels, rather than at the 3.6 degree increase that scientists previously considered the threshold for such effects. The IPCC concludes human activity has already caused a 1.8 degree increase in atmospheric temperatures, and at the current rate of greenhouse gas emissions, atmospheric temperatures will reach the 2.7 degree increase threshold by 2040. The report projects this would result in costs of $54 trillion (over an unspecified time period), roughly three times the GDP of the United States.

Emissions regulations received a lot of attention last month when the Trump administration announced its plan to replace the Obama-proposed Clean Power Plan with the Affordable Clean Energy Rule, which charges the states with developing plans to regulate greenhouse gas emissions from power plants. In addition to these types of command-and-control regulations, states will assume an increasingly important role in establishing market-based mechanisms for achieving emissions reductions. However, because wholesale electricity markets transcend state boundaries, questions remain about the limits of state authority. Two recent circuit court opinions considered whether state programs providing incentives to nuclear electricity generators impermissibly interfered with wholesale electricity markets. Concluding that the programs do not interfere with federal regulatory authority, the courts indicated that state authority to create clean energy policies is to be interpreted broadly.