Vinod Khosla has a letter in the Oct. 17 issue of Science ($ub. req'd) critiquing the Searchinger et al study: "U.S. croplands for biofuels increases greenhouse gases through emissions from land-use change."
Question: Why would the editors at Science publish a letter from someone who is not a biologist or a peer of the researchers being critiqued?
Answer: Searchinger et al were allowed to respond, and the response left a glowing crater where Khosla's argument once stood. Here's a sample:
The plight of the Amazon is a matter of both forestry and agriculture. Typical logging removes a few trees per hectare, causes collateral damage, and facilitates conversion through road-building, but forests regrow carbon if the land is not subsequently converted to agriculture. Biofuels that use good cropland anywhere in the world raise crop and meat prices and help spur the actual conversion to pasture or cropland by increasing their net economic return.
For cellulosic ethanol grown on corn land, our study found increased greenhouse gas emission, even with dramatically higher yields and conversion rates than now broadly attainable.
Yet even with major breakthroughs that double our assumed biomass yields, cellulosic ethanol grown on corn land would only reduce emissions compared with gasoline by 37% counting land-use change.
Even the latest hopeful DOE research plan in 2005 envisions 15 years of research and development before cellulosic production starts to scale up.
Although Khosla correctly points out that rising crop prices only modestly increase food prices in U.S. grocery stores, the poor around the world eat basic cereals and vegetable oil. Their prices worldwide rose 300 and 400% respectively, between 2000 and spring 2008. Nearly all analyses assign a major role to biofuels: Biofuels consumed the vast bulk of the world's growth in cereals and vegetable oil between 2005 and 2007, requiring the world to deplete stocks to meet growing food demand.
Sub-Saharan Africa already imports much of its food and has roughly 400 million hungry people [population of United States is 365 million] who together suffer 85% of the world's calorie gap. Climate change could decrease yields by 50% in the region.
... Sub-Saharan Africa needs to use its good arable land for food even more than other regions.
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Comments
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Whiskerfish Posted 7:00 am
23 Oct 2008
Whiskerfish in Africa
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vakibs Posted 10:58 pm
23 Oct 2008
The causes of deforestation are varied : most of this happens due to livestock rearing and subsistence agriculture. Yes, you heard me right : subsistence agriculture.
Take it from the bible of deforestation.
These issues are not directly tied to increased pressure on farmland due to biofuel cultivation. Yes, there is a link. But it is tenuous - not as strong as the biofuel antagonists claim.
Let's think in terms of eco-dollars.
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vakibs Posted 11:00 pm
23 Oct 2008
Let's think in terms of eco-dollars.
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eriqa Posted 7:05 am
24 Oct 2008
Or in other words, if we start growing more crops we are going to need more land, and there is not enough fallow land to accommodate all the fuel crops some want to grow. The fact that some of the land previously under cultivation, or some of the land currently being deforested, is subsistence farming, is irrelevant.
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vakibs Posted 6:55 pm
24 Oct 2008
With or without biofuel cultivation, there is going to be population pressures and people will be pushed onto virgin forestland. We need to rapidly find ways to accomodate these population in cities. Otherwise, biodiversity loss is a given.
Pointing fingers at biofuels is not going to solve the problem.
Let's think in terms of eco-dollars.
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Biodiversivist Posted 4:54 am
25 Oct 2008
Your link to the Amazon deforestation chart covered 2000-2005. Biofuel production just started hitting its stride in 2005. From above:
Biofuels consumed the vast bulk of the world's growth in cereals and vegetable oil between 2005 and 2007, requiring the world to deplete stocks to meet growing food demand.
Corn ethanol alone this year consumed 35,000 square miles of U.S prime cropland. As eriqa says, it's all about displacement. The food that went into our gas tanks created a 35,000 square mile hole that has been filled by some farmer somewhere in the world. It would take about eleven hours at highway speeds to drive around that hole. Biofuels barely represent 2% of global liquid fuel supplies. The more we produce the worse the destruction gets, the worse food supplies will be stressed.
35,000 square miles of prime cropland = 2% reduction in U.S. oil use.
Swapping a Subaru Outback for a Prius = 50% reduction in oil use, and no carbon sink destruction.
That's 2% VS 50%. Efficiency dwarfs biofuels as a way to reduce fossil fuel use. Biofuels are another stress on the planet's already collapsing biosphere and our food supplies.
It is unbecoming to take logical leaps, and point fingers at biofuel cultivation.
I would suggest that it is unbecoming to take illogical leaps, and not point fingers at biofuel cultivation.
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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