The most difficult task, phase-out over the next 20-25 years of coal use that does not capture CO₂, is Herculean, yet feasible when compared with the efforts that went into World War II. The stakes, for all life on the planet, surpass those of any previous crisis. The greatest danger is continued ignorance and denial, which could make tragic consequences unavoidable.

As you get more global warming, you should see an increase in the extremes of the hydrological cycle - droughts and floods and heavy precipitation.

A 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.

It's as certain that as long as fossil fuels are the cheapest energy, we will just keep burning them.

We have known since the 1800s that carbon dioxide traps heat in the atmosphere. The right amount keeps the climate conducive to human life.

The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change.

Policy decisions on climate change are being deliberated every day by those without full knowledge of the science, and often with intentional misinformation spawned by special interests.