JAMES HANSEN

As species are exterminated by shifting climate zones, ecosystems can collapse, destroying more species.

I tend to be naive and gullible, I guess, but I try to believe that governments believe what they say.

The evidence for human-made climate change is overwhelming.

Some Democrats deserve to be criticized.

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.

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.

You have no time to do the science if you're talking to the media.

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

What has become clear from the science is that we cannot burn all of the fossil fuels without creating a very different planet.

Jail threats did not dissuade Martin Luther King - and intergenerational justice is a moral issue of comparable magnitude to civil rights.

Until the public demands otherwise, the policy makers will continue to serve their financiers.

The democratic process is supposed to be one person one vote, but it turns out that money is talking louder than the votes.

Money has too big an influence on our politics in Washington and somehow we need to do something about that.

You can't turn on your television without seeing these advertisements about clean coal, clean tar sands and the claim that there's more jobs associated with fossil fuels than other industries. That's of course not true. But they're hammering that into the voters' heads.

We need to send a message to Congress and the president that we want them to take the actions that are needed to preserve climate for young people and future generations and all life on the planet.

Climate change is analogous to Lincoln and slavery or Churchill and Nazism: it's not the kind of thing where you can compromise.

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.

Consider the perverse effect cap and trade has on altruistic actions. Say you decide to buy a small, high-efficiency car. That reduces your emissions, but not your country's. Instead it allows somebody else to buy a bigger S.U.V. - because the total emissions are set by the cap.

Because cap and trade is enforced through the selling and trading of permits, it actually perpetuates the pollution it is supposed to eliminate.

The trains carrying coal to power plants are death trains. Coal-fired power plants are factories of death.

If your child gets asthma, the fossil fuel industry doesn't pay. Or if there's a natural disaster, the bill is paid by the taxpayer, not the fossil fuel company.

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.

Talking nice about sun and wind and green jobs is just greenwash.

After spending three or four years interacting with the Bush administration, I realized they were not taking any actions to deal with climate change. So, I decided to give one talk, and then it snowballed into another talk and eventually to even protesting and getting arrested.

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