President Barack Obama ordered the federal government to cut its greenhouse gas emissions 40 percent below 2008 levels by 2025, and mandated that at least 30 percent of its electricity come from renewable energy sources.

The executive order, which Obama signed Thursday morning, is the latest in a string of climate-related decisions the president has made in recent months to solidify his legacy on global warming in the face of Congressional gridlock. It also comes ahead of international climate treaty talks in Paris later this year, when all eyes will be on the United States, historically the world's top carbon emitter.

Obama's recent actions include vetoing a bill that would have fast-tracked a verdict on the controversial Keystone XL pipeline; banning drilling in Alaska's Bristol Bay; rolling out the Clean Power Plan to curb carbon emissions from coal plants; and in a joint announcement with China, pledging to cut U.S. emissions up to 28 percent below 2005 levels by 2025.

"We're encouraged to see this administration take a more aggressive stance in fighting climate change," said Karthik Ganapathy, a spokesman for the environmental group 350.org. "But in 2017, President Obama's decision on Keystone XL and the success or failure of COP 21 in Paris are what will really define his legacy on the issue. We're going to continue urging the White House to heed the science, and do what's necessary to prevent climate catastrophe."

With 360,000 buildings and 650,000 fleet vehicles, the federal government is the nation's largest consumer of energy. Federal agencies have already cut their emissions 17 percent since 2009 under Obama's direction and renewable energy not makes up 9 percent of their energy usage. White House officials said on Thursday the new 40 percent reduction goal would be the equivalent of taking 5.5 million cars off the road for one year. It is also expected to save taxpayers an estimated $18 billion in energy costs.

Major suppliers to the federal government from the technology, security, health and consulting industries also agreed to cut their emissions. This includes companies like IBM, GE, Honeywell, Hewlett-Packard, Northrup Grumman and Humana.

Rhea Suh, president of the Natural Resources Defense Council, called the executive order, "a powerful reminder of how much progress we can make simply through energy efficiency and greater reliance on clean, renewable sources of energy."

Greenpeace's climate and energy campaign director Kelly Mitchell commended the 40 percent reduction goal, but said the Obama administration, "needs to get serious about the federal government's much bigger carbon problem: Fueling the climate crisis by giving away our coal, oil, and gas from federal lands and waters."