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SOUTH AMERICA: A Cooler Way to Feed the World

Marcela Valente

BUENOS AIRES, Mar 27 2007 (IPS) - The growth in exports of agricultural and livestock products from the countries of the Southern Common Market (Mercosur) trade bloc poses an environmental dilemma, as half their greenhouse gases are emitted in rural areas.

Greenhouse gases are implicated in global warming. Most climate experts agree that human activity has been increasing the atmospheric concentration of carbon dioxide, methane, nitrous oxide and other greenhouse gases, thus contributing to planetary warming and climate change.

But now, experts in Argentina have designed a plan to cut the emission of methane during the process of digestion in cattle by up to 30 percent, based on a study carried out by scientists at the National University of the Centre of the Province of Buenos Aires (UNICEN).

The study looked at various ways of reducing enteric methane emissions in cattle. Enteric methane is produced by the breakdown of food by microorganisms in the rumen, the first stomach of cattle and other ruminants.

“The solution to the problem is a diet of pasture supplemented with balanced feed, with additives to improve the animals’ digestion, and more efficient herd management,” Roberto Gratton, a member of the research group that carried out the study, told IPS. These recommendations could be the key to increasing productivity in the livestock sector and reducing emissions of methane.

The study presents extensive information about gases emitted by cattle in Argentina, but also in Brazil, Paraguay and Uruguay, countries that, with Venezuela, are its Mercosur partners.

According to the study, 48 percent of the greenhouse gases emitted by Argentina, Brazil, Paraguay and Uruguay come from the agricultural and livestock sectors.

Global warming is normally associated with carbon dioxide liberated during the burning of fossil fuels. About 73 percent of global emissions are from fossil fuel burning, and in the case of the United States – the largest emitter – the proportion is 84 percent.

But in less developed countries which are more reliant on agriculture, the proportions are different. In Mercosur, where the rural sector is expanding due to food exports, the main concern is the countryside.

The coordinator of the inventory of Argentine greenhouse gas emission sources, Osvaldo Girardín, confirmed these facts for IPS, but pointed out that in contrast to other developing countries and regions, in Mercosur “forests are still very extensive, and biomass is not used as fuel (that is, wood fires are not generally used for cooking).”

This could compensate in part for rural atmospheric pollution, because forests act as carbon sinks. In any case, the proposals for reducing gas emissions in cattle appear to be easy to apply and would increase efficiency, he said.

Free-ranging cattle, which provide high quality beef, emit large amounts of methane. “Ninety six percent of this methane is generated by digestion in the rumen, and escapes through the mouth by belching,” Gratton explained.

An average animal belches up to 500 litres of methane a day, several sources say. According to data compiled by the UNICEN study, Argentina had 48 million head of cattle in 2002, capable of a considerable contribution to emissions of this gas.

The UNICEN experts used a device already in use in New Zealand to collect air samples near the animals’ muzzles, in order to take methane measurements during their experimental trials.

On the basis of their preliminary results, the scientists recommended nutritional and husbandry measures that may reduce methane emission while improving the efficiency of beef production.

“This is a preliminary study which will have to be repeated in different parts of the country, where pasture conditions and feeding regimes vary,” Gratton said.

“These are simple solutions that would lead to emission reductions of up to 30 percent. It is in the farmers’ interests to implement them, because there would be less energy loss per animal and productivity would be higher,” he said.

He said that the methane measurement technique had been tested in Uruguay on only one animal, rather than systematically, and that a pilot test is under way in Brazil. Research in Argentina, carried out with cooperation from New Zealand, appears to be further advanced.

Soya and rice crops, which cover vast areas in Mercosur, emit large quantities of nitrous oxide, another gas which contributes to global warming. But there are no prospects as yet for alternative methods of crop management that would reduce these emissions.

According to the Inter-American Institute for Cooperation on Agriculture, the region’s farming performance has been extraordinary in the last four years, partly due to favourable natural conditions, but also to technological investments and the unprecedented demand from Asia, which will continue in the medium term.

Brazil was the world’s largest exporter of beef in 2006, and it is also a leader in production and sales of pork and chicken. Argentina ranks third in global beef production, and Uruguay’s beef exports in 2006 set a new national record.

Brazil is also the second world producer of soya, behind the United States, and Argentina is the third. These countries are followed by China, India and Paraguay. As a bloc, Mercosur is the largest regional producer of soya, which is used as cattle feed and for oil extraction.

In spite of its small territory, Uruguay is the world’s sixth largest producer of rice. But this high level of food production has a downside: the contribution of these activities to global warming.

To quantify different greenhouse gases they are often expressed in terms of carbon dioxide equivalents. Since methane and nitrous oxide are produced mainly in the rural areas in Mercosur countries, and carbon dioxide in the towns and cities, the contribution of the rural sector to the total of these three greenhouse gas emissions can be calculated.

According to the UNICEN study, methane and nitrous oxide (measured in carbon dioxide equivalents) from the rural sector account for 52 percent of all three greenhouse gases in Argentina, 49 percent in Brazil, 51.5 percent in Paraguay and 81 percent in Uruguay.

The low proportion of carbon dioxide emissions in Uruguay is also due to the expansion of plantation forestry.