This post is by James Wang, Ph.D., a climate scientist at Environmental Defense.

Climate change denier and U.S. Senator James Inhofe (R-Okla) published a report just before Christmas with the headline: "Over 400 Prominent Scientists Disputed Man-Made Global Warming Claims in 2007." Does that leave you surprised and wondering? It shouldn’t. It’s a shocker of a headline, but the report itself doesn’t back up the claim.

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This post is by Michael Oppenheimer, Ph.D., the Albert G. Milbank Professor of Geosciences and International Affairs in the Woodrow Wilson School and the Department of Geosciences at Princeton University. He also serves as science advisor to Environmental Defense.

The award of the 2007 Nobel Peace Prize to Al Gore and the Intergovernmental Panel on Climate Change (IPCC) is an important milestone in the journey toward a global warming solution, and it got me thinking about how the IPCC came to be. To some extent, it was thanks to a miscalculation by the Reagan Administration!

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The author of today"s post, Lisa Moore, Ph.D., is a scientist in the Climate and Air Program.

Climate models are usually run far into the future, projecting temperature changes to the end of the century. Over the long term, the effects of greenhouse gases overwhelm all other factors. But climate can have substantial "short-term internal variability" – for example, temperature shifts due to El Niño and La Niña. Climate models have never been able to predict this internal variability – until now.

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The author of today’s post, Lisa Moore, is a scientist in the Climate and Air Program.

I’ve been reading a great book called Uncertain Science… Uncertain World by Henry Pollack – a readable and engaging discussion of decision-making in the face of uncertainty. Pollack argues that decision-makers use uncertainty as an excuse for inaction, when in fact it should be a stimulus for creativity and progress.

How sure do you have to be that something will happen to act on the possibility?

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The author of today’s post, Lisa Moore, is a scientist in the Climate and Air Program.

Stephen Colbert once quipped, "It’s not that I don’t believe in climate change, it’s that I don’t believe in climate. Have you ever heard anyone say, "How’s the climate?" No! They say, "How’s the weather?""

People often confuse climate and weather. They wonder how scientists can reliably predict climate 50 years from now when they can’t predict the weather a few weeks from now. The answer is that climate and weather are different, and it’s easier to predict climate than weather.

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Lisa Moore is a scientist in the Climate and Air Program.

Of everything in climate science, what seems to spark the most skeptical questions is our use of computer models. In this post and another to follow, I’ll talk about exactly what these models do, and how they contribute to our understanding of global warming.

I’ll start with why we use models in the first place. We want to project what will happen to our climate in the future – will it be warmer? How much warmer? Will it change in different ways in different places? Climate models use our knowledge of how the climate system works to calculate what different emissions scenarios mean for the future. Here’s how the models are built.

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This post is dedicated to the two great Americans we will honor on Presidents’ Day this Monday.

Everybody knows about Abraham Lincoln’s Emancipation Proclamation and Gettysburg Address; they are a big part of why Lincoln’s birthday is honored. Most people don’t know that Lincoln also established the National Academy of Sciences (NAS).

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Reports about the new 2007 IPCC assessment on climate change have been all over the news. The findings are sobering – the globe is warming largely because of human activities, the effects are already being felt, and if we don’t curb greenhouse gas pollution soon the consequences could be catastrophic.

But some folks are not so sure about this IPCC thing. They want to know: “What is the IPCC anyway, and why should I trust what they have to say?” Our good friends at the Wall Street Journal tell us not to trust the IPCC, it’s written by a bunch of “policymakers.” (See the editorial.)

Not so fast. Here’s what the IPCC really is. Read more »