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

Our own Scott Anderson is one of the experts featured in a new video on Carbon Capture and Sequestration (CCS). The video explains why CCS is an important tool in cutting emissions, and gives an animated description of how it works. It’s a good companion to Scott’s blog post on CCS.

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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This post is by Martha Roberts, an economist at Environmental Defense. It’s the first of 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

Global warming is occurring because – day after day, hour after hour – human activities pump large amounts of greenhouse gases into the atmosphere. One way to decrease emissions is to store carbon or CO₂ someplace other than the atmosphere.

There are two vastly different ways of sequestering carbon: biological and geological. The topic of this post is biological sequestration, which is among the biggest of the "low hanging fruits" for making quick, substantial cuts in emissions.

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Guest blogger Lisa Moore, Ph.D., is a scientist in the Climate and Air Program.

There’s always something new in climate change research. This week, scientists described the risks of geo-engineering, proposed an efficient way to reduce Arctic climate change, and discussed options for decreasing deforestation in developing countries.

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Yesterday I talked about the phenomenon of "global dimming", where pollution particles suspended in the atmosphere reflect sunlight back into space. Because they cause less sunlight to hit the Earth, these particles also cool the planet.

So here’s an idea for fighting global warming. Instead of trying to reduce greenhouse gas pollution – the root cause of the problem – why not use technology to counteract the effect of the pollution? For example, we could artificially add to the planet’s reflectivity so that the warming is cancelled by the cooling.

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Everybody’s always talking about reducing greenhouse gas emissions. What you don’t hear so often is a suggestion to clean up what’s already there. How would you do that? Good question! And it’s the question that Virgin Earth Challenge is posing to the world. Come up with a commercially viable way to remove a billion tons of CO₂ from the atmosphere per year, and win $25 million.

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