In the lead-up to the landmark Paris climate talks in December — an event that yielded a first-of-its-kind global agreement to cut carbon emissions — the Obama administration released a series of sweeping new environmental rules, each garnering both condemnation and deep-pocketed opposition from interest looking to torpedo the regulations in 2016.

As Obama enters the final year of his presidency, much of his focus on environmental issues will be implementing and preserving the work he's already done. If 2015 was the year he pushed his environmental agenda forward, 2016 could be the year he looks to preserve it.

Here are some of the biggest regulations Obama finalized or proposed last year, and how they'll be litigated in 2016.

Clean Power Plan

The most notable environmental rule issued in 2015 was the climate rule for power plants, an Environmental Protection Agency (EPA) regulation designed to cut carbon emissions from the power sector.