Wednesday, April 23, 2008

Uh-oh!

I thought that biofuels were the answer to all or problems, then I ran across this:


Biofuels could boost global warming, finds study. 21 September 2007 By Zoe Corbyn.


Growing and burning many biofuels may actually raise rather than lower greenhouse gas emissions, a new study led by Nobel prize-winning chemist Paul Crutzen has shown.1 The findings come in the wake of a recent OECD report, which warned nations not to rush headlong into growing energy crops because they cause food shortages and damage biodiversity.
Crutzen and colleagues have calculated that growing some of the most commonly used biofuel crops releases around twice the amount of the potent greenhouse gas nitrous oxide (N2O) than previously thought - wiping out any benefits from not using fossil fuels and, worse, probably contributing to global warming. The work appears in Atmospheric Chemistry and Physics and is currently subject to open review.
'The significance of it is that the supposed benefits of biofuel are even more disputable than had been thought hitherto,' Keith Smith, a co-author on the paper from the University of Edinburgh, told Chemistry World. 'What we are saying is that [growing many biofuels] is probably of no benefit and in fact is actually making the climate issue worse.'
"What we are saying is that growing biofuels is probably of no benefit and in fact is actually making the climate issue worse"- Keith Smith
Crutzen, famous for his work on nitrogen oxides and the ozone layer, declined to comment before the paper is officially published. But the paper suggests that microbes convert much more of the nitrogen in fertiliser to N2O than previously thought - 3 to 5 per cent or twice the widely accepted figure of 2 per cent used by the International Panel on Climate Change (IPCC).
For rapeseed biodiesel, which accounts for about 80 per cent of the biofuel production in Europe, the relative warming due to N2O emissions is estimated at 1 to 1.7 times larger than the quasi-cooling effect due to saved fossil CO2 emissions. For corn bioethanol, dominant in the US, the figure is 0.9 to 1.5. Only cane sugar bioethanol - with a relative warming of 0.5 to 0.9 - looks like a viable alternative to conventional fuels.
Some previous estimates had suggested that biofuels could cut greenhouse gas emissions by up to 40 per cent.2
Global picture
The IPCC's N2O conversion factor is derived using data from plant experiments. But Crutzen takes a different approach, using atmospheric measurements and ice core data to calculate the total amount of N2O in the atmosphere. He then subtracts the level of N2O in pre-industrial times - before fertilizers were available - to take account of N2O from natural processes such as leguminous plants growing in forests, lightning, and burn offs.
Assuming the rest of the N2O is attributable to newly-fixed nitrogen from fertilizer use, and knowing the amount of fertilizer applied globally, he can calculate the contribution of fertilizers to N2O levels.
The results may well trigger a rethink by the IPCC, says Smith. 'Should we go along the road of adding up the experimental evidence for each of the processes or are we better off using the global numbers?'
Critical reception
But other experts are critical of Crutzen's approach. Simon Donner, a nitrogen researcher based at Princeton University, US, says the method is elegant but there is little evidence to show the N2O yield from fertilized plants is really as high as 3-5 per cent. Crutzen's basic assumption, that pre-industrial N2O emissions are the same as natural N2O emissions, is 'probably wrong', says Donner.
One reason he gives is that farmers plant crops in places that have nitrogen rich soils anyway. 'It is possible we are indirectly increasing the "natural" source of N2O by drawing down the soil nitrogen in the world's agricultural regions,' he explains.
Others dispute the values chosen by Crutzen to calculate his budget. Stefan Rauh, an agricultural scientist at the Instituteof Agricultural Economics and Farm Management in Munich, Germany, says some of the rates for converting crops into biofuel should be higher. 'If you use the other factors you get a little net climate cooling,' he said.
Meanwhile, a report prepared by the OECD for a recent Round Table on Sustainable Development questions the benefits of first generation biofuels and concludes that governments should scrap mandatory targets.
Richard Doornbosch, the report's author, says both the report and Crutzen's work highlights the importance of establishing correct full life-cycle assessments for biofuels. 'Without them, government policies can't distinguish between one biofuel and another - risking making problems worse,' said Doornbosch.
Zoe Corbyn

4 comments:

Anonymous said...

I say, save the corn to make whiskey and we will get all the N2O we don't need from the GRB's.

Jim

Ernie Branscomb said...

GRB's? Like in gamma ray bursts?
Jim, have you been listening to Art Bell again.

I'm with you on the whiskey thing though. The world needs more whiskey.

I get a kick out of all the people that don’t realize where energy comes come. They talk about hydrogen / oxygen fuel, that when it burns combines to leave nothing but water. Ain’t that sweet?

Smart people know that you get hydrogen fuel by expending great amounts of electrical energy. More energy than they get back out of it. Where do they get the energy to make their super-clean fuel? Yep! Standard old coal-fired power plants. But, if they don’t think about it too hard, it goes away for them. I wonder why they don’t think about the fact that all the did was move the smokestack, but they used more energy and made more pollution.

Kym said...

NPR has been talking about the recent food riots being caused by farmers growing biofuels instead of food. Kinda an Orwellian color to the newscast these days.

Bob Flame, Ranger said...

If you haven't yet, check out "The Omnivore's Dilemma" by Michael Pollan for a good discussion on the impact of corn and soy on health, the economy and the globe. The biggest impetus towards American developed biofuels comes from the monstrous surpluses of corn grown with the generous help of our taxes through federal subsidies to the farmers. Corn price supports have created a system where it's cheaper to plow under other crops to grow more corn that we don't really need. With all the extra corn, we fatten our bodies with high fructose corn syrup and run our oil-sucking vehicles on sweeter-smelling fumes. Time Magazine also recently did a great piece on how this huunger for biofuels in the name of green energy is ripping down the Brazilian rainforests to convert to corn plantations even faster than the cattle drives of the past couple of decades.