SOUTH AMERICA: Tenacious Drought Puzzles Climate Experts

• by Marcela Valente* - Tierramérica (buenos aires)
• Friday, February 13, 2009
• Inter Press Service
• Tierramérica

'Climate change cannot be characterised by one single event, but rather by a series over the long term,' University of Buenos Aires climatologist Vicente Barros, member of the Intergovernmental Panel on Climate Change (IPCC), told Tierramérica.

Some experts believe the lack of rain could be related to the influence of La Niña, the cool phase of the cyclical climate event known as El Niño/Southern Oscillation, which changes the surface temperature of equatorial Pacific Ocean currents and affects the region's climate.

'La Niña is still very strong and the forecasting models aren't adjusted to reflect the disturbances it causes,' agricultural engineer Eduardo Sierra, an Argentina climate expert, finds himself explaining to someone almost daily.

In 2007, the IPCC and former U.S. vice-president Al Gore won the Nobel Peace Prize for their contribution to building knowledge and raising awareness among the public about climate change over the past two decades.

Because of the growing awareness of the phenomenon, 'now, with every event, they ask us if it's climate change,' says Barros with a laugh.

But the public's concern has a solid basis.

Although there have been some small rainstorms, the unusual lack of precipitation during the last several months of 2008 and so far in 2009 in southern and south-western Brazil, central and north-eastern Argentina, southern Paraguay and central and south-western Uruguay is causing million-dollar losses in the agricultural sector, food production and exports.

Barros, along with experts José Marengo of Brazil and Madeleine Renom of Uruguay, told Tierramérica that it is impossible to assert that the current drought is an unequivocal manifestation of climate change, because the weather changes must be assessed over the long term.

The three agree that 'what can be attributed to climate change is the greater climate variability, like fluctuations in the maximum and minimum rainfall, and the greater frequency, and in some cases the intensity, of extreme phenomena,' summarised Renom, meteorologist and professor at the University of the Republic of Uruguay.

In Argentina, noted Barros, there were more frequent intense storms with precipitation in the last 20 years in the central region - which indeed can be defined as a climate change.

The drought is hitting Argentina's most productive farming area: the central plains known as the Pampas.

Farmers estimate that the grain harvest was down 30 percent and report that 1.5 million head of cattle were lost. The Argentine government declared an agricultural emergency in the hardest hit areas, while meteorologists and agronomists are trying to forecast an end to the phenomenon.

In Brazil, where the people of the Northeast are accustomed to an arid climate, the lack of rain has surprised the southern states, where losses are being tallied in soybean and maize crops and in milk production. The states of Mato Grosso do Sul and Rio Grande do Sul were most affected.

In Passo Fundo, a Rio Grande do Sul municipality with 183,000 people, the situation is grave. According to the National Meteorological Institute, in December the city received less than half the normal precipitation, and in January, there was a slight improvement, but drought conditions persist.

'Even if it rains again, the loss is irreversible,' said João Chencarek, chief of civil defence in Mato Grosso do Sul. A drought at this time of year 'is uncommon and it caught the farmers off guard.'

For climatologist Marengo, of Brazil's National Institute of Space Research, 'the climate extremes are associated with natural variations. It cannot be affirmed that the affected area has become arid' in climate terms.

The lack of rain in southern Brazil coincides with La Niña, which reduces humidity in the atmosphere and causes a decline in precipitation in the area, said Marengo. However, he doesn't believe this drought is related to La Niña.

Officials in Uruguay have also declared a state of emergency. Affected are 25,000 square kilometres in the central and south-western parts of the country, whose total area is 176,220 square kilometres.

Damaged crops, forest fires, potable water shortages and livestock deaths are some of the consequences reported in Uruguay. Beef and milk production have also suffered, with milk falling from three million litres per day to just over one million, according to data from the Rural Federation.

Although rains this month have brought some relief, they are not enough to make up for the drought, Renom told Tierramérica.

As for La Niña, 'it has a strange dynamic, but it can't be blamed for everything,' because the precipitation deficit began before this phase in the Southern Oscillation began.

'We never predicted that this drought would last so long,' said Renom. To prevent some of the consequences of these events, more research is essential, she said.

Barros doesn't think the drought is the result of La Niña either. 'We can attribute part of what happened in November and December (to La Niña), but in January and February it no longer has an effect in our region. However, it could be that in March we will once again feel its impact,' he said.

Southern Paraguay also is suffering a shortfall in precipitation. Some areas went 40 days without rain, and others saw just 10 percent of normal rainfall.

For the 2008-2009 growing season, 2.5 million hectares were planted with soybeans, of which one million hectares will yield just one third of the previous harvest's total. There are also deep losses in maize, cotton and sesame.

'The behaviour of the rains is quite erratic,' Edgar Mayeregger, risk management coordinator for Paraguay's Agriculture Ministry, said in a Tierramérica interview.

'There are places where production is recuperating and others where the lack of a good, widespread rainfall is essential to overcome the problem,' he said.

In Mayeregger's opinion, the region is once again under the influence of La Niña. 'There were forecasts that indicated that it was going to tend to dissipate (in January and February), but now we are seeing these problems,' he said.

(*Additional reporting by Maria Eduarda Mattar from Rio de Janeiro, Natalia Ruiz Díaz from Asunción and Julieta Sokolowicz from Montevideo. This story was originally published by Latin American newspapers that are part of the Tierramérica network. Tierramérica is a specialised news service produced by IPS with the backing of the United Nations Development Programme, United Nations Environment Programme and the World Bank.)

© Inter Press Service (2009) — All Rights ReservedOriginal source: Inter Press Service

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