According to new research published Tuesday by the independent economic research firm Rhodium Group, emissions increased an estimated 3.4% in 2018 — marking the biggest jump in eight years.

Despite President Trump’s promise to withdraw from the Paris Agreement, the increase means the U.S. now has a rapidly shrinking window to meet the promises it made under the agreement in 2015.

Rhodium notes that the increases were exacerbated by Trump administration decisions to roll back regulations that limit greenhouse gas emissions. Emissions from electrical power generation, for example, were up 1.9%, despite coming largely from natural gas rather than coal as a near-record number of coal plants closed last year.

With the growing replacement of coal by natural gas and renewable energy, however, fossil fuel emissions have decreased, declining every year over the last three years. But the decreased reliance on coal has proven to be inadequate to offset carbon emissions, driven in large part by a lack of regulation on heavy industry — one of the biggest contributors to carbon emissions.

In order to counteract the effects of such emissions and halt climate change, more drastic measures will be required.