Climate 411

The Greenhouse Effect Explained

The author of today’s post, Bill Chameides, is Chief Scientist at Environmental Defense.

Last week we got a request to explain the Greenhouse Effect. Here goes.

The Greenhouse Effect

Source: National Park Service, U.S. Department of the Interior

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Posted in Basic Science of Global Warming / Read 4 Responses

Scientific Uncertainty

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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Posted in News / Read 4 Responses

Short-term Change and El Niño

The author of today’s post, Bill Chameides, is Chief Scientist at Environmental Defense.

Last week in our Suggestion Box we got this question:

I’ve compiled a NCDC state by state average temperature map and trends from 1895 thru 2006. 1998 was the warmest year, but years since then are showing either the same as 1998 or cooler in most states. How can I explain to people why average temps haven’t been warming EVERY year since 1998 instead of going up and down?

This is a good question, and one I get fairly often, so let me try to explain.

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Posted in News / Read 8 Responses

Signs of Global Warming

In reading the news this week, I was struck by how many reports there were from around the world of problems related to global warming. Here’s what I found:

Warming poses threat to Chesapeake
Washington Post, July 20, 2007

China says climate change drying up major rivers
Yahoo! News – Reuters, July 16, 2007

Warming may bring hurricanes to Mediterranean
Yahoo! News – Reuters, July 16, 2007

Glacier in retreat
New York Times, July 17, 2007

Climate change threatens Italy’s Po River delta
Yahoo! News – AFP, July 17, 2007

I also came across an interesting article in the Washington Post about by a guy who went around the world visiting places affected by global warming. The descriptions are, um, chilling.

Posted in News / Read 3 Responses

Global Warming from Soot

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

Most people don’t realize it, but "black carbon" or soot – the same stuff that dirties up chimney flues and car mufflers – is a significant contributor to global warming. Today’s best estimates place it next in line behind the greenhouse gases CO2 and methane (see Table 2.13 in the IPCC report).



Soot particle under a microscope. Credit: D.M. Smith, University of Denver.

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Posted in Arctic & Antarctic / Read 5 Responses

Climate Models: How Good Are They?

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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Posted in News / Read 3 Responses