The bottom billion people don't contribute at all to climate change - maybe 1 percent of emissions, they could double or triple their emissions and the climate would not be destabilised.

We have 20 years [until 2026] to reduce carbon emissions or climate change will become irreversible.

Don't ask what global climate protection can do for your country; ask what your country can do for climate protection.

The planetary machinery tends to be jumpy, this is to respond disproportionately to disruptions that come with the manmade greenhouse effect.

In a sense the U.S. is climate illiterate. If you look at global polls about what the public knows about climate change even in Brazil, China you have more people who know about the problem and think deep cuts in emission are needed.

Either the Earth System would undergo major phase transitions as a result of unchecked human pressure on nature's capacities and resources or a "Great Transformation" towards global sustainability would be initiated in due course. Neither transitions nor transformations will be manageable without novel forms of global governance and markets.

When you imagine that if all these 9 billion people claim all these resources, then the earth will explode.