President Obama signed a presidential memorandum Wednesday establishing that climate-change impacts must be factored into the development of all national security-related doctrine, policies and plans.

The move signals Obama’s determination to exercise his executive authority during his final months in office to elevate the issue of climate in federal decision-making, even though it remains unclear whether his successor will embrace this approach.

Under the directive, 20 federal agencies and offices that work on climate science, intelligence and national security must “collaborate to ensure the best information on climate impacts is available to strengthen our national security” through the new Federal Climate and National Security Working Group. That group must release a climate change and national security action plan in 90 days. All the relevant agencies must then identify steps to implement it.

Speaking to reporters on a conference call, White House officials said this would spur a more specific and focused strategy when it comes to both identifying how different regions of the world would be affected by climate change and how to respond.

“Simply put, our agencies want to protect our nation against this threat,” said Alice Hill, special assistant to the president and senior director for resilience policy at the National Security Council. She added that the memorandum establishes “a unified approach to identify the priorities for the federal government.”

John Holdren, the president’s top science and technology adviser, said changing weather patterns and other climate impacts — including drought, more-intense storms and rising sea levels — are already exacerbating regional conflicts and “straining the capacity of the United States and allied armed forces to deliver humanitarian and disaster relief.”

White House aides described the directive as the culmination of a year-long effort to more fully integrate climate considerations into intelligence analysis and military planning. While the next president could easily overturn it, Holdren said the changes underway in the atmosphere, on land and at sea will ensure that agencies continue on their current course.

“There’s every reason for the next administration to follow this blueprint,” he said. “In fact, the impacts on national security are only going to grow.”

But Sen. Lindsey O. Graham (R-S.C.), who in the past has supported federal limits on greenhouse gas emissions to curb climate change, said in an interview that Obama’s new memorandum was “elevating it beyond where it needs to be right now.”

“Climate change is real. I think it’s a problem that needs to be solved … but I think the president is making a huge mistake to interject climate-change solutions into national security,” he said, adding that it could hamper some of the military’s efforts. “If I’ve got to choose between climate-change solutions and solutions that will put Iran in a box, and they may be carbon intensive, I’m going to go with putting Iran in a box.”