We have known since the 1800s that carbon dioxide traps heat in the atmosphere. The right amount keeps the climate conducive to human life.
James HansenOnly in the last few years did the science crystallize, revealing the urgency - our planet really is in peril. If we do not change course soon, we will hand our children a situation that is out of their control.
James HansenIf we drive our fellow species to extinction, we will leave a far more desolate planet for our descendants than the world we inherited from our elders.
James HansenHow long have we got? We have to stabilize emissions of carbon dioxide within a decade, or temperatures will warm by more than one degree... We don't have much time left.
James Hansen