Global warming isn't a prediction. It is happening.
Adding CO2 to the air is like throwing another blanket on the bed.
The five warmest years over the last century occurred in the last eight years.
What we are doing to the future of our children, and the other species on the planet, is a clear moral issue.
It's as certain that as long as fossil fuels are the cheapest energy, we will just keep burning them.
Scientists will say we can't blame global warming for any single event. In a sense that's right, but the fact that the frequency and intensity of these events is increasing you can blame on global warming.
Tipping points are so dangerous because if you pass them, the climate is out of humanity's control: if an ice sheet disintegrates and starts to slide into the ocean there's nothing we can do about that.
As species are exterminated by shifting climate zones, ecosystems can collapse, destroying more species.
Coal is responsible for as much atmospheric carbon dioxide as other fossil fuels combined and it still has far greater reserves. We must stop using it.
Until the public demands otherwise, the policy makers will continue to serve their financiers.
Talking nice about sun and wind and green jobs is just greenwash.
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.
The evidence for human-made climate change is overwhelming.
With a fourth generation of nuclear power, you can have a technology that will burn more than 99 percent of the energy in the fuel. It would mean that you don't need to mine uranium for the next thousand years.
Several times in Earth's history, rapid global warming occurred, apparently spurred by amplifying feedbacks. In each case, more than half of plant and animal species became extinct. New species came into being over tens and hundreds of thousands of years. But these are time scales and generations that we cannot imagine.
What makes tar sands particularly odious is that the energy you get out in the end, per unit carbon dioxide, is poor. It's equivalent to burning coal in your automobile.
I was lucky to grow up at a time when it was not difficult for the child of a tenant farmer to make his way to the state university.
Jail threats did not dissuade Martin Luther King - and intergenerational justice is a moral issue of comparable magnitude to civil rights.
As a government employee, you can't testify against the government.
I have been described as the grandfather of climate change. In fact, I am just a grandfather and I do not want my grandchildren to say that grandpa understood what was happening but didn't make it clear.
