Why I must speak out about climate change

TED2012 · 17:51 · Filmed Feb 2012

Top climate scientist James Hansen tells the story of his involvement in the science of and debate over global climate change. In doing so he outlines the overwhelming evidence that change is happening and why that makes him deeply worried about the future.

TED Talk

JAMES HANSEN: WHY I MUST SPEAK OUT ABOUT CLIMATE CHANGE

… the longer we wait, the more difficult and expensive it becomes. If we had started in 2005, it would have required emission reductions of three percent per year to restore planetary energy balance and stabilize climate this century. If we start next year, it is six percent per year. If we wait 10 years, it is 15 percent per year — extremely difficult and expensive, perhaps impossible. But we aren’t even starting.

17:10 So now you know what I know that is moving me to sound this alarm. Clearly, I haven’t gotten this message across. The science is clear. I need your help to communicate the gravity and the urgency of this situation and its solutions more effectively. We owe it to our children and grandchildren.

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James Hansen
Climatologist

James Hansen has made key insights into our global climate — and inspired a generation of activists and scientists. 🔗 Full bio