The Vatican has yet another strange bedfellow in its expanding ecological alliance, hosting anti-capitalist eco-crusader Naomi Klein at a conference on saving the planet.

Klein, author of "This Changes Everything: Capitalism vs. the Climate," acknowledged Wednesday that she never expected to be invited to the Vatican, "as a secular Jewish feminist."

But she told a Vatican news conference that Pope Francis' recent encyclical on the environment and the global economic system that is threatening it spoke to her. She said it should inspire those who use the Bible to defend man's domination of nature and deny climate change to change their ways.

The Vatican has come under fire from conservatives for hosting the U.N. chief and Jeffrey Sachs at another climate conference, given their support for access to contraception.