Climate 411

This post is by Sheryl Canter, an Online Writer and Editorial Manager at the Environmental Defense Fund.

On Monday, the Washington Post reported that new studies say carbon output must be near zero to avert danger. They referred to two recent studies, one published in Geophysical Research Letters and one in the journal Global Biogeochemical Cycles.

I asked the scientists here at EDF about this. It turns out what’s missing from the Washington Post article is the time frame. Yes, we have to bring emissions to near zero, but it doesn’t have to be tomorrow. And moreover, this isn’t news!

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This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

January 2008 was the coldest month in several years, according to the scientific groups that track global temperature. Is it true, as DailyTech concludes, that January’s cold "wipes out a century of warming"? Has global warming stopped?

In a word, no. A single month does not make for a climate trend. Let’s look at the data.

Source: Raw data from the U.K.’s Met Office Hadley Centre (see description of data).

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This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

In a comment on my Global Warming Crib Sheet, johnmashey asked if I could say something about the lifetimes of greenhouse gases – that is, how long different greenhouse gases stay in the atmosphere. Great idea! Here’s a whole post on it.

Many people don’t realize that the greenhouse gases we emit can stay in the atmosphere for decades, centuries or even millennia. That’s why it’s so important that we cap emissions as soon as possible.

Here’s a table showing a selection of greenhouse gases, their global warming potential (GWP), and their lifetimes:

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This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

The science behind global warming is, well, science, and it can get pretty technical. By how many degrees has the globe already warmed? How much more can it warm before we’re in trouble? How much carbon dioxide is in the air now, and how much more can we afford to emit before risking climate catastrophe? Which are the most important greenhouse gases? And what do all those funny abbreviations mean?

Below you will find a handy crib sheet that gives you all these numbers and more.

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This post is by John Balbus, M.D., M.P.H., Chief Health Scientist at Environmental Defense.

A federal appeals court decided last week that a U.S. Environmental Protection Agency (EPA) rule exempting coal- and oil-fired power plants from cutting toxic mercury pollution violates the Clean Air Act and is unlawful. The court rebuked EPA for attempting to create an illegal loophole for the power generating industry rather than applying the toughest emission standards of the Clean Air Act (see full text of decision [PDF]).

The ruling invalidates the agency’s so-called "Clean Air Mercury Rule," which allowed power plants that fail to meet emission targets to buy credits from plants that exceeded targets, rather than installing mercury emissions controls of their own. In other words, the EPA wanted to use a cap-and-trade system with mercury – a highly toxic substance.

Fourteen states, dozens of Native American tribes, public health and environmental groups (including Environmental Defense), and organizations representing registered nurses and physicians challenged the EPA’s mercury rules. Are you surprised that Environmental Defense opposed a cap-and-trade system? It’s because mercury is a toxin, and cap-and-trade doesn’t work with toxins.

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This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

The term "tipping point" refers to a critical threshold at which a small change can qualitatively alter the state of a system. For example, when temperature reaches 32°F, ice changes into water. There also are "tipping points" in global warming. The best known is the Greenland Ice Sheet, which could begin a slow, irreversible meltdown if global temperature passes a certain threshold.

Last week, climate researchers published a paper that examines Earth systems in danger of passing tipping points due to human activity. They call these "tipping elements", and highlight nine such systems from around the world. They say the greatest threat is to the Arctic, followed by the Greenland Ice Sheet. Here’s the list.

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