DOCTORS FOR DISASTER PREPAREDNESS NEWSLETTER

Could the fact that plants thrive in environments with high levels of carbon dioxide offer a “silver lining to the otherwise dark clouds of climate change?” asks Ned Stafford, a freelance writer based in Germany (Nature 2007;448:526-528).

Stafford accepts without question the assertion that the CO₂ greenhouse effect will bring losses in crop yield, owing to “higher temperatures, flooding, drought and rising sea levels.” But even if enhanced levels of CO₂ plant food “go at least some way towards offsetting the losses in yield,” some are “sounding alarm bells” about the nutritional value of crops, regardless of abundance. Protein levels might drop, with deleterious effects on foraging cattle and beet armyworms. Bread quality could fall because of less gluten in wheat. Soy might contain less calcium, potato tubers might have less vitamin C, and many foods might be deficient in micronutrients, causing “hidden hunger.”

In a university-issued press release, Professor Andreas Fangmeier, professor of plant ecology and ecotoxicology at the University of Hohenheim, warned that “by 2050, CO₂ concentrations could make French fries poisonous, beer foamless, and wheat flour unbakeable.” He didn't actually bake any bread, just performed some chemical analyses that indicated a “potential” problem, and admitted that the press release was exaggerated.

The timing of the Nature article seems to have more to do with the recent push for carbon controls than with research news. In 2002, an analysis of 159 peer-reviewed articles showed that increasing the ambient CO₂ concentration by 150—450 ppm resulted in 19% more flowers, 18% more fruits, 16% more seeds, and a 25% increase in total seed mass (Jablonski LM, New Phytologist 2002;156:9-26). Instead of heralding the great news, Environment News Service trumpeted the finding that mean seed nitrogen across all the species studied decreased by 14%, under the headline “More Carbon Dioxide Could Reduce Crop Value.” Global-change websites quickly disseminated the alarm.

Although all the studied crops were more productive with higher CO₂ concentrations, only wheat and barley showed an decrease in seed nitrogen content. Maize, soybeans, and rice–which exhibited a 42% increase in seed number–did not. Higher levels of nitrogen fertilization offset the decrease totally (Idso SB et al., CO2science.org 10/16/02). CO₂ enhancement increased the Vitamin C content of tomatoes, sour oranges, bean sprouts, and strawberries. Other antioxidants also increased (CO2science.org).

Though world population growth is leveling off, human numbers are still increasing. Industrialized countries are withdrawing large areas of land from cultivation. Idso and Idso concluded that aerial fertilization by projected increases in CO2 will be barely sufficient to assure the agricultural productivity needed to forestall mass starvation (Forecasting World Food Supplies: the Impact of the Rising Atmospheric CO₂ Concentration; 2000).

But the starve-the-biosphere campaign proceeds at all levels of government. A county official urges symbolic CO₂ emissions reductions. A federal judge rules that the Bush Administration “unlawfully withheld action” required under the Global Climate Change Research Act of 1990 by missing a deadline–“a stern rebuke of the administration's head-in-the-sand approach,” said the Tucson-based Center for Biological Diversity.

FOOD CROPS, HABITAT DISPLACED TO GROW FUEL

To grow the corn, convert it to ethanol, and truck it to gas stations (it cannot be moved in pipelines) took billions of gallons of water, millions of pounds of fertilizers and pesticides, and the energy-equivalent of 9 billion gallons of gasoline. It is economically feasible only because of a 51 cents/gal subsidy for blending ethanol into gasoline and a 54 cents/gal tariff on imported ethanol to keep out cheaper products from Brazil.

Corn prices have nearly doubled, and livestock owners can't afford to feed their animals. The Cattlemen's Beef Association is demanding an end to subsidies and tariffs for ethanol. Sen. Saxby Chambliss (R-GA), a big supporter of ethanol, introduced a bill that would cap the amount that could come from corn (Wall St J 5/18/07).

Ethanol is not exactly clean and green. While burning ethanol-containing fuels reduces emissions of benzene and butadiene, it increases formaldehyde, acetaldehyde, and ozone. Ozone-related respiratory deaths in LA could increase by 9% (SF Chron 4/18/07).

Other plant sources of ethanol have a higher yield than corn but are not yet technically feasible in the U.S. (LA Times 5/17/07).

The rush to grow biofuels is causing social disruption and major changes in land use. Hundreds of thousands of small landholders have been displaced by soybean plantations in South America, which supply 40% of Brazil's biofuels. NASA has correlated the market price of soybeans with the destruction of the Amazon rainforest, currently 325,000 hectares/y. With food and fuel crops competing for land and water, the price of staples is expected to rise 20—33% by 2010, and 26—135% by 2020. Calorie consumption decreases as prices rise, in a ratio of 1:2 (Int Herald Tribune 7/10/07).

And the effect on emissions? Clearing tropical forests for sugar cane ethanol emits 50% more greenhouse gases than the production and use of the same amount of gasoline.

Animals and humans can't eat coal or petroleum. But these wonderful fuels enable us to grow more food, first by providing energy and second by releasing essential plant food in that very process. A big step beyond keeping coal and oil in the ground is to sequester carbon from plant decomposition. Heating plant residue without oxygen, a process called pyrolysis, converts it into biochar. Some energy is generated from the exhaust gases as heat, electricity, biofuel, or hydrogen. But instead of burning the biochar to offset hydrocarbon fuel use, some suggest putting it back into the soil, so that bioenergy generation is not merely carbon neutral but withdraws a net 20% of carbon from the atmosphere.

Using forests as a carbon sink is a temporary measure, as forests mature over decades or centuries and start to release the carbon. Or a forest fire could release it quickly. Biochar diffused in the soil could tie up the carbon for millennia (Lehmann J, Nature 447:143-144).

Not even food is exempt from carbon scrutiny. Dole Food Company has announced a project to establish a “carbon-neutral” supply chain for bananas and pineapples.

Is It Simply Madness?

“Imagine a better world” is the title of a review of the book The World Without Us by Alan Weisman (Nature 2007;448:135-136). “Given that humans are here to stay on Earth for some time, what can we do to lessen our impact?” asks reviewer Stuart Pimm of Duke University. Since we have “placed constraints on recovery” of our originally untainted Planet, as by introducing species that “don't belong” where we put them, “there is no guarantee that even with all the pieces, we would be able to put nature back together again.” Still, nature would begin reclamation very quickly. “Trees would flourish,... and most domesticated crop plants would die within the year.”

Intended or not, mass death could be the consequence of a carbon-rationing regime.

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