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

In IPCC’s Third Assessment Report (2001), scientists reported that carbon dioxide (CO₂) and methane levels were higher than at any time in the past 420,000 years. In their latest report (2007), IPCC scientists raised the number to 650,000 years.

Last week, scientists again revised the number upward. New research shows that CO₂ and methane levels are higher today than they have been in at least 800,000 years.

Here’s how they know.

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

An article in this week’s Nature predicts that Europe and North America will cool slightly over the next decade. No, this doesn’t mean that global warming has stopped.

The new paper describes a climate model that makes short-term (decadal) predictions based on ocean dynamics. The decade-long cooling is just a temporary offset to warming from human activity. After it passes, temperatures will begin climbing again. By 2030, the model forecasts the same global temperatures as the IPCC.

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

Last week, NOAA released some disheartening numbers: both CO₂ and methane increased sharply last year. Growth rates are increasing (see graph to the right).

The CO₂ numbers weren’t a surprise. A paper with similar findings was published last November by a team that included a NOAA scientist. I wrote a blog post summarizing the study, which analyzed the reasons behind the trend (see Rise of Atmospheric Carbon is Accelerating).

The methane numbers, however, were disturbing. Until this year, methane levels have been essentially unchanged since 1998.

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

There’s an email making the rounds lately – an invitation to take a Global Warming Test. It starts off reasonably enough (yes, global warming is real), but then quickly devolves into ridiculousness – ridiculousness presented in a way that looks misleadingly "scientific".

For those interested in truth, here are the real answers to the Global Warming Test.

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

This month, while Arctic sea ice hits its annual wintertime high (such as it is – see last week’s post), Antarctic sea ice reaches its summertime low.

We’ve already posted about the British Antarctic Survey’s report of a vast ice berg on the verge of breaking off the Wilkins Ice Shelf. Here’s more on what’s happening at the South Pole from NASA’s recent briefing on polar sea ice.

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

Last summer we saw record-shattering shrinkage of Arctic sea ice caused, in part, by human-induced global warming. Last week I listened in on a NASA briefing on polar sea ice, and this year looks no better.

This winter was relatively cold due to a strong La Niña, so the Arctic saw a modest increase in overall sea ice (slightly above the record low of 2005-2006, but still below the long-term average). However, the older, thicker ice that lasts through the summer has declined sharply, and this is very worrying.

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

A huge Antarctic ice berg – seven times the size of Manhattan – is close to breaking off, supported only by a thin strip of ice hanging between two islands.

Part of the Wilkins Ice Shelf, the berg was captured in satellite and video images by British Antarctic Survey (BAS), which said, “It is another identifiable impact of climate change on the Antarctic environment.”

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

According to NOAA’s National Climatic Data Center, this past winter was the coolest since 2001. A single season can’t determine a long-term trend any more than a single month can (see my previous post, "Did Global Warming Stop in January?"). But the recent cooler temperatures do offer an opportunity to talk about La Niña – a climate pattern that causes short-term cooling.

This winter’s La Niña is the strongest (coldest) since 1989, so we’d expect the weather to be cooler than usual. But even so, the cooling didn’t come close to offsetting the warming of the past 50-100 years. As you can see in the graph below, the cooling barely takes us back to 2001.

Data source: NASA. Each dot is a three-month period (season).

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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 Scott Anderson, an attorney and senior policy advisor at the Environmental Defense Fund. It’s the second in a three-part series on carbon sequestration – storing carbon or carbon dioxide (CO₂) in soils, trees, geological formations, and oceans.

1. Biological Sequestration
2. Geological Sequestration
3. Ocean Sequestration

To stop global warming, the U.S. must substantially move away from carbon-emitting fossil fuels to clean renewable energy. But a transition of this magnitude takes time. Right now this country is heavily dependent on coal for electricity, and traditional coal plants are none too clean.

How do we stop global warming while renewable technologies to meet our energy needs are still under development? Part of the answer may lie in an emerging transition technology called Carbon dioxide (CO₂) Capture and Storage (CCS). The idea behind CCS is to capture the CO₂ from industrial processes like coal plants, and then store it in deep geological formations.

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