Aileen Getty set up a fund that helps to bank-roll groups such as Just Stop Oil, which aim to force the Government to alter policy via “civil disobedience”.
The American’s grandfather was the late J Paul Getty, once the world’s richest man and patriarch of a dynasty worth £4billion.
Ms Getty, 65, established the Climate Emergency Fund two years ago – and it is claimed she donated nearly £1million.
Speaking from her home in California, she said: “It’s true that over a century ago, my family played a role in unlocking fossil fuels at a time when we did not know what we know now, that the extraction and use of fossil fuels is killing life on our planet.”