In view of the immense power of natural weather and climate fluctuations and the great buffering capacity of the Earth, especially the ocean, it is easy to be skeptical about whether small anthropogenic changes of atmospheric composition can have important practical impacts.
James HansenA level of no more than 350 ppm is still feasible, with the help of reforestation and improved agricultural practices, but just barely - time is running out.
James HansenBurning all the fossil fuels will destroy the planet we know, Creation, the planet of stable climate in which civilization developed.
James HansenGlobal warming has already triggered a sea level rise that could reach from 6 metres (19.69 ft) to 25 metres (27.34 yards).
James Hansen