Monthly Archives: June 2011

Good Soil, Good Carbon Sink

Did you know? Improving our current agricultural practices could be an enormously effective way to reduce the amount of CO2 in our atmosphere. Little things like composting, keeping fields planted year-round, reducing tillage, and increasing plant diversity could be enough to substantially increase the amount of carbon captured in soil.

From Discover Magazine:

“Ohio State University soil scientist Rattan Lal says the agricultural soils of the world have the potential to soak up 13 percent of the carbon dioxide in the atmosphere today—the equivalent of scrubbing every ounce of CO2released into the atmosphere since 1980.”

There are currently several projects under way around the world to test the carbon capture potential of soil-enrichment strategies.

In California, soil scientist Whendee Silver of UC Berkeley is working with ranchers and local and state land management organizations on the Marin Carbon Project to study the effect of compost from yard and agricultural waste on carbon storage. She’s projecting that “28 million acres of grazing land in California could absorb 42 million tons of carbon dioxide—nearly 40 percent of what the state’s electrical power plants produce in a year.”

In Australia, soil ecologist Christine Jones worked with ranchers to increase soil’s carbon capture potential by growing grasses that stay green all year round. Now she is working on providing incentives: accurately measuring the carbon capture so that they may be compensated for the amounts they’ve sequestered.

You can get the details at Discover Magazine.

A New Use for Sewage

This is supposed to be old news, but this is the first time I’m hearing about it! So here, meet the Bitublock. Six times stronger than cement, and made completely of post-consumer waste material.

“Designed by engineer John Forth, of the University of Leeds in England, the blocks are produced with a mixture of waste materials, including crushed glass, pulverized fuel ash, incinerated sewage, steel slag, and other waste products that would normally wind up in landfills or, worse, wherever they happen to be discarded. Further, less energy is required to make the Bitublocks than is needed for concrete. These products are bound together by bitumen, (a byproduct of crude oil distillation used widely in road construction), before compacting it in a mould to form a solid block. Next the block is heat-cured, which oxidizes the bitumen so it hardens like concrete. This makes it possible to use a higher proportion of waste in the Bitublock than by using a cement or clay binder.”

My only issue with this is that, if it does replace cement as our construction material of choice, it would still require enormous amounts of bitumen to produce, and I’m guessing we won’t be able to use the asphalt from old worn roads. And just to give you an idea of how much bitumen would be needed to replace our current construction needs, UK’s International Cement Review just reported a couple of months ago that worldwide cement consumption is forecast to reach a record 3859 megatonnes in 2012. While that would mean taking megatonnes of waste materials out of our ecosystem, all those benefits will be offset by the carbon emissions and toxic pollution from mining and shipping megatonnes of bitumen to build these Bitublocks… that’s hardly ideal.