Wednesday, November 29, 2006

Manure Mania

Cow manure may not be an obvious energy alternative, but it is fueling farms in Vermont. Central Vermont Public Service started a program called Cow Power, which uses methane from cow dung to generate electricity.

Methane, a green house gas that traps 20 times more heat than carbon dioxide, can significantly contribute to global warming. Trapping it and using it for fuel can help to reduce energy costs and potentially slow climate change.

Some dairy farms install a machine that scrapes floor of the barn, collecting waste from the cows. The manure is then put into a 100 degree holding tank, called an anaerobic digester, where bacteria that is naturally found in the cows’ stomachs continue to digest it like an enlarged stomach.

Over the course of three weeks, methane is collected from the manure in the sealed tank and sent to a natural gas engine where it is used to create electricity. Unless it leaks, there is no reek. And the heat from the engine helps to keep the digestion tank hot.

Some of the remaining waste is in liquid form while the rest is solid. Farmers can spread liquid over the farm fields as fertilizer. The now odorless solid can replace sawdust that is spread on the floor of the bar and used as bedding for the cows.

One cow can produce up to 30 gallons of waste a day, which can light two 100-watt light bulbs 24 hours a day, according to the website. Maybe best of all, the fuel is renewable.

Cow power not only supplies farms with energy, it can also provide energy to other institutions. Green Mountain College announced in October that it would purchase 50 percent of its energy from cow power.

Although cow manure may not be an energy alternative for everybody, it certainly is an option that doesn’t stink.

Tuesday, November 21, 2006

Cooling Forest Fires

Scientists now think that forest fires could actually decrease global warming.

Forests absorb carbon dioxide in the atmosphere, creating what scientists call carbon sinks. Global warming causes droughts and longer summers, so there are more forest fires, which destroy these sinks and release carbon dioxide back into the atmosphere. But a new study published in the journal Science shows that when there are fewer northern boreal forests, more light is reflected back into space, decreasing the absorption of greenhouse gases in the atmosphere.

After a northern forest burns to the ground, scientists think that evergreen forests will be replaced by deciduous forests when the earth is warmer. These deciduous saplings have lighter green leaves than mature trees, so they reflect more light. They also shed their leaves in the fall and winter, so snow that falls to the ground will also reflect more light.

How's that for an unexpected negative feedback loop? After all this talk about how global warming is going to fuel itself, this study show that we still don't exactly know all the systems in play.

Tuesday, November 07, 2006

Plastic Ocean

The ocean can absorb heat from the sun and carbon dioxide from the air, but it can't absorb our plastic trash. A report released yesterday by Greenpeace states that plastic people threw away and was subsequently dumped into the ocean is now part of the marine environment and (surprise, surprise) is harming animals.

"Marine debris has become a pervasive pollution problem affecting all of the world’s oceans. It is known to be the cause of injuries and deaths of numerous marine animals and birds, either because they become entangled in it or they mistake it for prey and eat it," the report reads.

So what we throw away does not actually go "away" after all! It does to the extent that most people just don't see it floating in the ocean, even though a select few have observed it first hand. Carl Safina, an ecologist and award-winning writer, points out some of the dangers of garbage that he saw in the oceans in his book Voyage of the Turtle, released earlier this year.

I'm not advocating a toothbrush reuse program or anything, but I don't think it hurts to know that discarded plastics are swimming among the fish.

Friday, November 03, 2006

Fish Food

If you like your sushi, you may be able to savor each bite for just a few more decades. The fish that we currently eat could be fished out by 2050, a new study published in the journal Science concludes. With each species that we fish nearly to extinction, the ecosystem deteriorates, the scientists found.

"Unless we fundamentally change the way we manage all the oceans species together, as working ecosystems, then this century is the last century of wild seafood," said co-author Steve Palumbi of Stanford University in an article published by the National Science Foundation.

The four-year study is the most comprehensive yet, the article states, including historical, observational, and experimental data. It also supports what scientists observed on a smaller scale.

The less biodiversity, the less resistant the ecosystem is to other stresses. If we protect our ocean ecosystems, however, we could extend the estimated drop-dead date. Even though we seem to be sending ocean environments into a downward spiral, the more species we protect, the healthier the ecosystem will be.

Thursday, November 02, 2006


Whole Foods has started selling wind cards. What are wind cards you ask? They are similar to gift cards, but instead of being redeemable for a product, they help the wind energy industry to market their product. Shoppers can buy cards in $5 or $15 amounts, representative of the cost of energy for an individual or a household per month, reported Planet Ark. The grocery store bought wind power in January to offset the company's dirty energy costs. Renewable Choice Energy, which is selling the cards with Whole Foods, provides the market with its wind power credits.

On the Renewable Choice Energy website, the company advertises a free gift card to Whole Foods if you sign up to pay for a monthly card. It is not clear, however, exactly whether the cost is meant to offset individual or household carbon emissions by purchasing clean energy, or if the money is just for industry marketing.

The idea of some sort of carbon card is not new. This summer, David Miliband, the environmental secretary of the UK, proposed a personalized carbon card system. Each UK citizen would get a certain number of carbon "points," which would be deducted depending on what that person did. Drive a Hummer and your points are spent in an instant. Thankfully, you can buy more. The system hasn't been implemented yet, so we will have to see if it works.

Regardless of the form they take, the cards are a nice reminder of what it costs to fuel the way we live, whether you buy into it or not.