James Hansen
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.Collection: Technology
Global warming isn't a prediction. It is happening.
Adding CO2 to the air is like throwing another blanket on the bed.
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.
On a per capita basis, Britain is responsible for more of the carbon dioxide now in the atmosphere than any other nation on Earth because it has been burning it from the dawn of the Industrial Revolution.
You can't tie a rope around the ice sheet. You can't build a wall around the ice sheets.
Jail threats did not dissuade Martin Luther King - and intergenerational justice is a moral issue of comparable magnitude to civil rights.
What has become clear from the science is that we cannot burn all of the fossil fuels without creating a very different planet.
The five warmest years over the last century occurred in the last eight years.
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.
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.
The United States did not sign Kyoto, yet its emissions are not that different from the countries that did sign it.
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.
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.
As a government employee, you can't testify against the government.
Some Democrats deserve to be criticized.
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.
What is frustrating people, me included, is that democratic action affects elections but what we get then from political leaders is greenwash.
The democratic process is supposed to be one person one vote, but it turns out that money is talking louder than the votes.
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.
The evidence for human-made climate change is overwhelming.
Climate change is analogous to Lincoln and slavery or Churchill and Nazism: it's not the kind of thing where you can compromise.
You have no time to do the science if you're talking to the media.
Talking nice about sun and wind and green jobs is just greenwash.
Until the public demands otherwise, the policy makers will continue to serve their financiers.
What we are doing to the future of our children, and the other species on the planet, is a clear moral issue.
We have known since the 1800s that carbon dioxide traps heat in the atmosphere. The right amount keeps the climate conducive to human life.
I've tried to be a straight scientist doing the science and reporting it as best I can.
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.
The fact is fossil fuel carbon will stay in the surface climate system for millennia.
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.
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.
I tend to be naive and gullible, I guess, but I try to believe that governments believe what they say.
As species are exterminated by shifting climate zones, ecosystems can collapse, destroying more species.
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.
The trains carrying coal to power plants are death trains. Coal-fired power plants are factories of death.
It's as certain that as long as fossil fuels are the cheapest energy, we will just keep burning them.
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.
Because cap and trade is enforced through the selling and trading of permits, it actually perpetuates the pollution it is supposed to eliminate.
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.
Being at NASA and having the access to both computing capability and satellite observation capability is kind of the ideal research situation to try to understand global climate change.
Money has too big an influence on our politics in Washington and somehow we need to do something about that.
We have at most ten years—not ten years to decide upon action, but ten years to alter fundamentally the trajectory of global greenhouse emissions.Collection: Years
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.Collection: Impact
Imagine a giant asteroid on a direct collision course with Earth. That is the equivalent of what we face now with climate change, yet we dither.Collection: Motivation
Global warming has already triggered a sea level rise that could reach from 6 metres (19.69 ft) to 25 metres (27.34 yards).Collection: Sea
If humanity wishes to preserve a planet similar to that on which civilisation developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO₂ will need to be reduced from its current 385 ppm [parts per million] to at most 350 ppm... If the present overshoot of this target CO₂ is not brief, there is a possibility of seeding irreversible catastrophic effects.Collection: Humanity
We are on the precipice of climate system tipping points beyond which there is no redemption.Collection: Climate
Politicians think that if matters look difficult, compromise is a good approach. Unfortunately, nature and the laws of physics cannot compromise - they are what they are.Collection: Thinking
It would be immoral to leave young people with a climate system spiraling out of control.Collection: Inspirational