Climate 411

Ozone Alert For Plants

By Lisa Moore / Bio / Published: August 7, 2007

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

If you’re in or near a big city, you’ve probably heard your local news give ozone alerts. Those warnings mean that smog levels are high enough to affect your lungs. Even moderate pollution causes respiratory problems for kids with asthma. Really high levels of ozone make it dangerous for even the healthiest adult to be outdoors.

Now scientists are warning that smog could make global warming worse because of its effects on plants.

Also posted in Plants & Animals / Read 1 Response

Extreme Weather Across Europe

By Bill Chameides / Bio / Published: July 27, 2007

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

A week or so ago I wrote about all the recent extreme weather in the United States. Well, it’s not just happening here. Great Britain is being hit by the worst flooding in decades, and it keeps on raining. A heatwave blanketing south-eastern Europe has killed hundreds of people, and out-of-control wildfires are burning across Greece.

Is this global warming? It’s impossible to say for sure what causes a particular weather event, but global warming does make extreme weather events more likely. Whether or not the events in Europe are due to global warming, I do think the Europeans are, unfortunately, getting a taste of things to come. For more, visit our Web page on global warming and extreme weather.

Also posted in Extreme Weather / Comments are closed

The Greenhouse Effect Explained

By Bill Chameides / Bio / Published: July 25, 2007

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

Also posted in Basic Science of Global Warming / Read 4 Responses

Global Warming from Soot

By Lisa Moore / Bio / Published: July 19, 2007

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.

Also posted in Arctic & Antarctic / Read 5 Responses

Extreme Weather: This Season's Norm?

By Bill Chameides / Bio / Published: July 17, 2007

With all that’s going on in the world, it’s easy to miss weather events. So you may not have noticed that U.S. weather patterns the last few months have been quite extreme and worrying.

From NOAA’s National Climatic Data Center

Also posted in Extreme Weather / Read 50 Responses

Part 5 of 5: The Only Explanation Left

By Bill Chameides / Bio / Published: July 12, 2007

This is the final installment of a five-part series by Bill Chameides on How We Know Humans Cause Global Warming.

1. A 175-year-old Puzzle
2. What Chemistry Tells Us
3. Causes of Past Climate Change
4. The Medieval Warming Period
5. The Only Explanation Left

Compared to 100 years ago, the temperature of the atmosphere is warmer. No one disputes that. And no one disputes that an extra source of heat must be causing it – that’s a basic law of physics. But how do we know that the source of the heat is increasing levels of greenhouse gases from burning fossil fuels and deforestation?

So far in this series I’ve described how the relationship between atmospheric carbon dioxide (CO₂) and global warming was discovered, how carbon isotopes prove that rising CO₂ concentrations are from the burning of fossil fuels, and how the orbital shifts that cause ice ages cannot explain our recent warming.

That certainly suggests that global warming is caused by increased CO₂ from burning fossil fuels, but how can we be sure?

Also posted in Basic Science of Global Warming / Read 22 Responses

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