You won’t find Rupert Murdoch’s niece Eve Kantor (number 6 on our rich crusaders list) on the BRW Rich 200 or in Who’s Who. But she and her husband, Mark Wootton, have given away at least $50 million in the past 15-20 years to protect Australia’s environment.

A big whack of that — about $10 million — has gone to the Australian Conservation Foundation, whose ultra-chic, green headquarters, 60L, in Melbourne’s inner suburb of Carlton, was a gift from the couple’s Poola Foundation, which originally commissioned the building.

An even bigger lump — about $14 million — has gone to the Climate Institute, which Eve and Mark set up from scratch in 2005 to lobby for action on global warming and warn about the consequences of doing nothing to reduce carbon emissions.

According to Wootton, half the $50 million they’ve spent has been matched by other people, so the total is closer to $75 million. Often, Eve’s four brothers and sisters and her mother, Anne Kantor, have put up the rest.

Another brother, Tom Kantor, who was a filmmaker and indigenous activist until his death in 2001, has contributed most of all by making Eve and Mark the beneficiaries of his estate and instructing them to give his money away.

The Kantor family fortune — which is reckoned to be still about $250 million — comes largely from uncle Rupert, who bought Anne and her two sisters out of the News Corp empire during the 1990s. Anne, who is five years younger than her famous brother, has used some of the money to fund Clive Hamilton’s Australia Institute, which is the nation’s leading left-wing think tank.

This and the Kantors’ green-left activism has put them at odds with Murdoch’s newspapers in Australia, which have been famously sceptical of man-made global warming, and contemptuous of greenies and the Greens.

But these rows haven’t persuaded the Kantors to pull back. Indeed, quite the opposite. “One of the reasons we do this,” Mark Wootton tells The Power Index bluntly, “is because of some of the things the Murdoch papers have done.”

The first skirmish between the two came in 2006, when the Kantor-backed Climate Institute paid $160,000 for a series of ads in the nation’s newspapers — including The Australian — attacking the Howard government for doing nothing about climate change.

But the stand-off got nasty last May when Rupert’s Sunday Telegraph let fly at “Carbon Cate” Blanchett, accusing the “multimillionaire Hollywood star” of sparking “outrage in the community” and being “out of touch” for agreeing to front the “Say Yes” campaign, urging Australians to back a carbon price. The TV and newspaper ads, which ran right across the country, were partly paid for by the Climate Institute, but just about everyone in the Kantor family chipped in to meet the cost.

Wootton admits that it can be “difficult” for them, and that “Anne (Kantor) is in a difficult space because of it”. However, their views are not entirely unrepresented in the Murdoch clan. Family matriarch, Dame Elisabeth, supported the “Say Yes” campaign, and got bagged by News’ neanderthal columnist, Piers Akerman, for doing so. (Akerman claimed she was too old to know what she was saying, and had been “used”). Melbourne theatre director Michael Kantor (Eve’s brother) also put his name to it. And according to Wootton, the differing views do not cause great friction. He cites a recent family gathering in Melbourne where they were all welcomed, and everyone got on fine.

But why do they want to give all their money away to such a cause? Wootton is the son of a Presbyterian missionary who worked in South Korea, so he comes from “a very strong social justice background”. Kantor grew up in a wealthy, eastern suburbs family, who went camping, bushwalking, and loved nature.

“We’ve been together now for 30 years,” says Wootton with disarming frankness, “and it hasn’t always been the most easy thing in our life, her huge wealth. We’ve got four kids and we’ve made a decision with them that we don’t want to pass it on; we don’t want them to end up with inherited wealth. It can be good, but it can also destroy people.”

*Read the full profile at The Power Index