Environment Forum

Global environmental challenges

From illegal landfill to natural urban oasis

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The green hill in the distance looks to be natural but then you think “hang on, this is Dallas. There aren’t any hills here … ”

The hill, in fact, masks what was once an illegal landfill filled with cast off debris. The garbage now lies beneath a thick clay cap to prevent the methane, a greenhouse gas on steroids, from seeping out. Natural grass has been planted on the top.

Nearby fish-filled ponds mark the gateway to a 6,000 acre ecosystem which is the largest urban hardwood forest in the United States. And it is all just minutes away from historically disadvantaged and mostly black neighborhoods on the south side of Dallas.

I had been meaning to visit the Trinity River Audubon Center, a partnership between the city of Dallas the National Audubon Society, since it opened in October of last year. I got a gap the other day and it was an eye-opening visit.

Baa baa green sheep, have you any grass?

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Farming often gets a bad wrap for causing global warming but at least two sheep in Norway are doing their bit to go green.

Grass has been growing on the backs of the sheep on the island Vega off Norway’s northwest coast — apparently from seeds that fell onto them during the night when they were sleeping in a shed under some stacks of hay.

Cow manure to combat global warming?

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A cow looks out from the barn at Smith’s Country Cheese in Winchendon, Massachusetts in this June 30, 2008 file photoCould cow manure curb global warming?

A study by scientists in Texas reckons that cows, sheep, pigs, chickens and other farm animals excrete enough waste to generate electricity for millions of homes, helping reduce reliance on coal-fired power plants and so cut greenhouse gas emissions released by burning fossil fuels.

Left to decompose naturally, manure emits the powerful greenhouse gases methane and nitrous oxide. If trapped by a devoted workforce (people with an impaired sense of smell encouraged to apply) the gases could used to drive microturbines to generate electricity. That works by the manure being “anaerobically digested” — a process a bit like making compost — to release energy-rich biogas which would be burnt to drive the microturbines.

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