Billionaire Virgin Group Chairman Richard Branson on Thursday committed an estimated $ 3 billion over the next 10 years, or all of the profits from his airline and rail businesses, to combating global warming.

We are very pleased today to be making a commitment to invest 100 percent of all future proceeds to the Virgin Group from our transportation interest, both our trains and airline businesses, into tackling global warming, Branson told a news conference at the Clinton Global Initiative in New York. We have to wean ourselves off our dependence on coal and fossil fuels. Our generation has the knowledge, it has the financial resources and as importantly it has the will power to do so.

Most international experts say emissions of greenhouse gases, mainly from burning fossil fuels in power plants, factories and cars, are the primary cause of a 1.1 F (0.6 C) rise in temperatures over the past century.

A dwindling group of scientists says that the dominant cause of warming is a natural variation in the climate system, or a gradual rise in the sun's energy output.

We must not be the generation responsible for irreversibly damaging the environment. We must hand it over to our children in as near pristine condition as we were lent it from our parents, Branson said.

Branson's announcement comes one day after the Bush administration said it was committing $ 3 billion to climate technology research and development. Climate experts and members of Congress criticized the administration's plan as long-delayed and inadequate.