The climate dice are now loaded. Some seasons still will be cooler than the long-term average, but the perceptive person should notice that the frequency of unusually warm extremes is increasing. It is the extremes that have the most impact on people and other life on the planet.

The carbon emissions from tar shale and tar sands would initiate a continual unfolding of climate disasters over the course of this century. We would be miserable stewards of creation. We would rob our own children and grandchildren.

Recent warming coincides with rapid growth of human-made greenhouse gases. The observed rapid warming gives urgency to discussions about how to slow greenhouse gas emissions.

Adding CO2 to the air is like throwing another blanket on the bed.

Interference with communications of science to the public has been greater during the current administration than at any time in my career.

The question is not whether to close the parks, but how to accomplish this goal.

If 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.