In March 2007, we blogged about the dire situation of the South Pacific islands Kiribati and Tuvalu. The sea is rising due to global warming, and two uninhabited islands nearby have already sunk. Now Kiribati is preparing for extinction:

The leader of the South Pacific island nation of Kiribati laid out an extraordinary plan Monday (Sept. 22) that would scatter his people through the nations of the world as rising sea levels submerge the islands they have called home for centuries.

Rising sea levels are submerging the land. Land not yet submerged is being rendered uninhabitable by salty ground water.

This post is by Sheryl Canter, an online writer and editorial manager at Environmental Defense Fund.

What if, instead of reducing the greenhouse gas concentrations that hold excess heat in our atmosphere, we injected something in the atmosphere to reflect sunlight back into space? That's the idea behind sulfate geo-engineering. As Bill wrote in his post "Can we engineer our way out?", there are a plethora of problems with geo-engineering, but scientists still study it as an option of last resort.

The idea of injecting sulfates into the atmosphere is based on the observation that large volcanic eruptions can cause short-term global cooling. But in addition to the usual problems with geo-engineering (for example, it does nothing to stop ocean acidification from excess CO₂), scientists have found a new one. Sulfate geo-engineering could endanger food and water supplies for billions of people in Africa and Asia, according to a recent paper in the Journal of Geophysical Research [PDF].

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Last week, the New York Times Dot Earth blog posted a sobering video of coastline erosion in Alaska. This is no simulation - it's a time-lapse video made from pictures taken two hours apart from late June to late July of this year.

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Last Thursday, the Global Carbon Project released its annual report on the state of the carbon cycle, Carbon Budget 2007 [PDF]. It emphasizes (as we reported earlier this year) that CO₂ levels are continuing upward, and the rate of increase is accelerating.

One reason for the acceleration in CO₂ concentrations is higher fossil fuel emissions. Despite rising fuel prices, global CO₂ emissions from fossil fuels rose 3 percent in 2007. That's just slightly below the average increase of 3.5 percent per year since 2000.

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Old-growth forests hold vast amounts of carbon from centuries of growth, and this carbon would be released into the atmosphere if the trees were cut down. That much has been known for a long time, which is why Environmental Defense Fund so strongly advocates a plan to reduce deforestation in developing countries.

But new research shows that old-growth forests are even more important than previously thought. According to a new study in Nature, old-growth forests aren’t just standing there maintaining the status quo. They still actively take up CO₂ from the atmosphere.

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There was an interesting story in Tuesday's New York Times about a unique weather station in upstate New York next to the Mohonk House resort. Most cooperative observer stations move over time, or the area around them is built up, or the observers and observing methods change. Not so at Mohonk.

At Mohonk, the weather observations are done as they were 112 years ago, and only a handful of people have recorded the over 41,000 readings. Plus Mohonk has an extensive database of wildlife sightings, a 77-year record of Mohonk Lake water quality, and an 83-year record of local phenology (the timing of events such as frost, blooms and migrations) - all observed by the same handful of people. This makes the site's data uniquely valuable:

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Have Hurricanes Gustav and Hanna gotten you thinking about the possible link between hurricanes and climate change?

Check out our hurricane and clilmate change overview for the straight facts from EDF climate scientists. And Peter Black shares eye-opening maps over on ClimateAtlas.

This post is by Sheryl Canter, an online writer and editorial manager at Environmental Defense Fund.

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

Just when we're finally having the kind of national conversation we need about global warming, those who are ignoring scientific evidence are making a last-gasp effort to divert our attention: They're sneaking myths and deceptions into America's science classrooms.

In Louisiana's recent "Science Education Act", they joined forces with advocates of teaching creationism under the guise of promoting "critical thinking" on select scientific topics, including climate change. Signed into law by Governor Bobby Jindal, the law actually provides cover for teachers who want to promote perspectives not founded in science.

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

Have you ever spent time scrolling through NASA's image gallery? Some of the pictures are mesmerizing. I particularly like the "Blue Marble" image of the Earth (at right), which was stitched together using satellite data.

Satellites provide more than pretty pictures. Our ability to understand and predict climate change depends on continuous high-quality satellite data.

Unfortunately, this critical data stream is threatened by budget cuts and lack of political support. In 2005, the National Academies assessed the situation and deemed it "alarming". Three years later, the outlook has not improved.

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

In 1992, the world's nations gathered to negotiate the United Nations Framework Convention on Climate Change. The 192 nations that ratified this treaty - including the U.S. - agreed to the following objective:

[T]o ... prevent dangerous anthropogenic interference with the climate system… within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

The definition of "dangerous" is a social and political judgment that is informed by science. But even if we all agreed on which outcomes we wanted to avoid, scientists couldn't say precisely how much we have to cut emissions to achieve these outcomes. We have good best estimates, but there's always a degree of scientific uncertainty.

Here's why.

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