Tuesday, November 24, 2015

The Promise of Seaweed--A Third Way Technology


C.Coimbra photo


Editor's Note: This is part of an excerpted series of a Yale Environment 360 interview by Richard Schiffman, with Tim Flannery, an Australian scientist and author.  He discusses how “third way technologies,” that mimic the earth’s natural carbon-removing processes could provide a critical tool for slowing climate change.


e360: You are really hopeful about seaweed farming. How would that work? 

Flannery: Seaweed grows at 30 to 60 times the rate of land-based plants, so it can draw out lots of C02. One study suggests that if you cover 9 percent of the world’s oceans in seaweed farms, you could draw down the equivalent of all our current emissions — more than 40 gigatons a year — and grow enough protein to feed a population of 10 billion people. That’s a huge opportunity. 

Seaweed farms can also reverse ocean acidification. Off the coast of China, there are about 500 square kilometers of seaweed farms that are used to produce edible seaweed for the food market. They have been very well studied, and we’ve seen there that pH can rise as high as 10 around those seaweed farms. At the moment with an acidified ocean it is 8.1. You could buffer oceans and they are fantastic places for growing fish, shellfish, or prawns, just because of that buffering impact. But you then have the problem of what to do with all that seaweed. You certainly don’t want it just sitting there and rotting away. One of the proposals is that bio-digesters be used. These are very familiar to famers, the kinds of things you put your agricultural waste in and generate methane, which you can use to produce electricity. 

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