A coalition of conservative and free-market groups is lobbying lawmakers to amend a major defense policy bill that would ensure climate change is no longer part of the Pentagon's planning and operations going forward.

"These climate programs and policies have nothing to do with the mission of the United States' Armed Services," said a letter sent to House members by the coalition on Wednesday. "In fact, many of these programs and policies are likely to undermine military readiness by diverting scarce resources to such things as helping state and local governments to 'go green,' meeting targets for reducing carbon dioxide emissions, meeting a variety of green energy quotas, meeting fleet requirements for low and zero emissions vehicles, and incorporating climate resilience and preparedness as principal aims of land and water management."

The libertarian Competitive Enterprise Institute is leading the lobbying effort, and Myron Ebell, Trump's former head of transition for the Environmental Protection Agency, signed the letter with over a dozen others.

The letter asked House members to support an amendment offered by Rep. Warren Davidson, R-Ohio, to the National Defense Authorization Act, which if enacted would prevent the Department of Defense from continuing to implement former President Barack Obama's Executive Order 13693, which orders all federal agencies to cut greenhouse gas emissions. "This executive order requires the Department of Defense to create a number of climate change programs and policies throughout the Department," the letter stated.

The letter pointed out that President Trump did repeal a similar Obama-era executive order that required the Defense Department to develop "comprehensive plans that integrate consideration of climate change into agency operations and overall mission objectives." But other climate orders have been overlooked and also must be dismantled, according to the groups.

"Rep. Davidson's amendment would continue President Trump's work and further curtail the Department of Defense's unnecessary and irrelevant forays into climate change policy," the letter said.

As of Thursday, 17 groups had signed onto the letter urging the House to pass the defense authorization bill with the Davidson amendment. The House is taking up amendments to the bill this week.

The new signatories that joined the effort on Thursday include: Joe Bast, the CEO of The Heartland Institute, Tom Pyle, president of the American Energy Alliance, and Judson Phillips, founder of Tea Party Nation.