And while most US evangelical Christians tend to vote Republican, the environmental cause is more associated with the Democratic Party, Cizik said in a Reuters interview.

"There are people who disagree with what I'm doing ... within the evangelical community of America," he said.

"Simply for standing up and saying, 'Climate change is real, the science is solid, we have to care about this issue because of the impact on the poor' -- why would that be controversial? Well, I'm sorry to say, it is controversial and there are people who want to take my head off."

As vice president for governmental affairs of the National Association of Evangelicals, Cizik has been a high-profile advocate for a spiritual motivation for environmental activism.

Cizik is part of an overall ecological push by evangelical Christians known as "creation care," the notion that the environment is a divine creation and must be protected by humans.

This movement included a highly successful pitch to evangelicals to use more fuel-efficient vehicles, dubbed "What Would Jesus Drive?" The title was inspired by the popular bromide, favored by Christians including President George W. Bush -- "What Would Jesus Do?"

DIVINE JUDGMENT

For the last three years, Cizik and others have pushed evangelicals to think hard about the environment, and pushed just as hard to make evangelicals' environmental worries known to policy-makers.

Cizik spends much of his time on Capitol Hill, but declines to specify which legislators are his targets. Instead, he stresses the political force evangelical Christians can be.

Noting a recent survey that showed one-third of Americans regularly attend an evangelical church, Cizik said, "It's an amazing figure, and I don't think there's a member on the Hill, Republican or Democrat, who can't imagine evangelicals talking and thinking about these (environmental) issues."

For evangelical Christians, Cizik said, "The Bible is authoritative in our lives, in our personal actions ... that's not to say that the Bible dictates one bill or another -- of course it doesn't. But it dictates stewardship of our natural resources."

Those who fail to care for the environment will face a divine reckoning, he said.

"Never mind what the voters say or do, there will be a judgment by God himself on these matters and it's a very serious consideration ... for this president, any senator, any House member, if you think about these issues in terms of what the Bible says."

When confronted with projections that half of all species may be extinct by the end of this century, Cizik sees a "biblical concern."

"God made 'em," he said of endangered species. "And He says we are to exercise a stewardship responsibility of this earth ... We're tenant-landlords and we will have to return it at some point, at the end of time, to God who made it. And are we going to return it in the condition it was made?"

A familiar presence on Capitol Hill and a frequent interview subject on US television, Cizik also appears in a new environmental documentary film called "The Great Warming," narrated by actor Keanu Reeves and singer Alanis Morrisette.

He admires the hit environmental film "An Inconvenient Truth," and gives its star, former Democratic Vice President Al Gore, full marks.

"The critics say the vice president is just engaging in hysteria," Cizik said of Gore's film presentation. "Not true. The vice president is simply stating the scientific facts that I happen to agree with on climate change."