President Trump’s energy agenda calls for drilling more oil and gas, something that could take years. But he took other actions this week that could more quickly affect the way the country prepares for and adapts to climate changes driven by the burning of fossil fuels.

In 2021, President Biden ordered the Pentagon and Department of Homeland Security to study the security implications of climate change and to incorporate them into defense strategy and other national security plans.

The Biden administration, in a final push to shore up the nation’s pandemic preparedness before President-elect Donald J. Trump takes office, announced on Thursday that it would nearly double the amount of money it was committing to ward off a potential outbreak of bird flu in humans.

Federal health officials have been keeping a close eye on H5N1, a strain of avian influenza that is highly contagious and lethal to chickens, and has spread to cattle. The virus has not yet demonstrated that it can spread efficiently among people.