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Antidote for Urban Heat: More Trees

When the temperature shoots up, cities usually feel the heat the most. But some cities feel the heat more than others.

Scientists studying urban heat islands in 42 cities in the Northeastern U.S. have found that the greatest temperature differences between urban areas and the surrounding environment are in places you might not expect. Continue reading

Carbon Storage Could Be Shaky Proposition

Underground storage of CO2 could trigger earthquakes

Some say storing carbon underground as a way to curb greenhouse gas emissions is risky. The container has to last essentially forever, and what if an earthquake rips through the seal? But new research is showing that pumping CO2 underground could itself trigger earthquakes. Continue reading

Creating Carbon Sponges

Carbon capture demo at the annual American Geophysical Union meeting. Credit: Molly Samual.

Carbon capture demo at the annual American Geophysical Union meeting. Photo: Molly Samuel

Almost lost amid the Copenhagen media clutter was last week’s meeting of the American Geophysical Union in San Francisco. So this week we’re playing a little catch-up. Lauren Sommer has the second of three posts on things that caught our attention at AGU.

Carbon capture technology has largely focused on the most convenient emissions sources–namely the stacks at large power plants. But as Columbia University’s Allen Wright showed at the American Geophysical Union conference in San Francisco last week, there are other ways to do it.

Wright and colleagues demonstrated their “air capture” technology, where carbon dioxide is absorbed straight from the air by something that looks a lot like a gadget for cleaning Venetian blinds. It’s a special plastic material with a sponge-like consistency. Once the carbon is absorbed, the material is exposed to water or water vapor which causes the carbon to be released. It can then be captured. Wright says it captures CO2 three to five times better than a leaf in full sunlight.

On a large scale, this technology might be built into “artificial trees” that could be stationed anywhere around the globe. The prototype, designed by Wright’s Global Research Technologies, doesn’t look much like a tree. It’s a shipping container with a circular, rotating basket on top where the air capture units are exposed to the air. After one rotation, the baskets would be brought “downstairs” where the carbon is captured. From there, the carbon could be geologically sequestered or even used to make beverages bubbly.

Of course, the main criticism of this approach is efficiency. Carbon dioxide is only about 0.04% of the atmosphere, which is why more concentrated sources like power plant stacks get more attention. Wright says capturing carbon from power generation will be important, “but capture at the stack isn’t enough. It won’t do what has to be done. Air capture has the advantage of being able to deal with emissions from anywhere on the planet from any source.”

Cars are one of the sources he’s talking about. Their prototype unit is designed to capture a ton of carbon a day, which would neutralize the emissions from about 20 cars. They hope to get the cost of each carbon-capturing unit down to the price of car, so the cost of reducing a ton of carbon could one day be similar to other technologies.

Still, to make an impact on global emissions, millions of these units would need to dot the landscape. And just as with renewable energy, NIMBY issues are a potential roadblock. But as is a common refrain these days, Wright says if we’re serious about cutting emissions, we’ll need every technology that shows promise.

CA is “Extra Vulnerable” to Climate Change

3115732217_d7901f1545_m.jpgClimate change will most likely affect California more dramatically than it does many other places, according to researchers speaking Tuesday at the American Geophysical Union’s annual meeting in San Francisco. The panel featured new research into climate change impacts on sea level rise, agriculture, water evaluation and planning, air pollution, and extreme climate events.

Climate researcher Dan Cayan, from the Scripps Institution of Oceanography, described California as “extra vulnerable” to climate change and gave a broad (and somewhat scary) overview of the reasons why. The state’s temperature increases are expected to be similar to the global average temperature rise in the coming decades, making for hotter summers with longer heat waves. Given the expected increase in population in California’s interior, longer and harsher heat waves could have significant public health implications.

On top of the more intense summers and milder winters, precipitation across the state may well decrease, especially in Southern California. These drier conditions will be compounded by a significant withering of the Sierra snowpack. Even with a moderate increase in temperature (2 degrees C), Cayan says more than half of the historic California snowpack will disappear by 2100, as the mountains get more rain than snow at higher elevations. That can increase flooding and coupled with expected sea rise over the next century, the San Francisco Bay and the Sacramento/San Joaquin Delta may be in for some extreme events.

Fortunately, others are looking into sea level rise and what it’s going to mean for the San Francisco Bay Area and the coast of California. Peter Gleick, president and founder of the Pacific Institute, spoke about a new study currently under review focused on the projected impacts of sea level rise, including flooding and erosion, and the potential responses. The study will evaluate flood and erosion potential, create detailed maps of California’s vulnerable areas, estimate risks to populations and structures, anticipate costs of various adaptation strategies, and make policy recommendations. Gleick cited one immediate need as a catalog of the state’s existing levees and their conditions.

The report’s results should be out in February, which is also when we should see the draft version of the first California Adaptation Strategy, which aims to compile information on expected climate change impacts for the state and provide policymakers and resource managers with strategies for addressing them.