HEALTH-ARGENTINA: Climate Change Spawns Return of Diseases

By Marcela Valente Reprint | | Print |

Marcela Valente

BUENOS AIRES, Nov 6 2001 (IPS) - Climate change, the effects of which have begun to be felt in Argentina, has led to the reappearance of tropical diseases for which the population is unprepared, to the extent that international experts are already referring to “the case of Argentina.”

Emissions of greenhouse gases that cause global warming affect the entire planet. But in more vulnerable regions like Argentina, the impact on human health is more obvious, at least to those investigating the links between climate change and outbreaks of disease.

Epidemiologist Rodolfo Carcavalo, a member of the Intergovernmental Panel on Climate Change, told IPS that the subtropical climate seen in northern Argentina is extending farther and farther to the south.

The panel of scientific researchers and government delegates was created by the Conference of Parties to the United Nations Framework Convention on Climate Change, which addresses the question of targets for curbing the greenhouse effect.

Greenhouse gas emissions – including carbon dioxide – created by the burning of coal, gas and oil, cause the warming of the earth’s surface and a change in the global climate by trapping the sun’s heat in the atmosphere.

But the greenhouse effect tends to be more closely identified with weather phenomena like drought, heat waves, floods and hurricanes, than with a rise in infectious diseases like malaria and dengue, and the extinction of species of flora and fauna.

Due to its geographic location and proximity to the South Pole, Argentina is particularly vulnerable to the effects of global warming.

In some cases, the changes have been positive. For example, in the semi-arid central Argentinian province of San Luis, farm production and the quality of livestock – which has traditionally been poor in that region – have improved significantly in recent years, due to an increase in rainfall, while the number of animals per hectare has mushroomed.

Something similar is occurring in the northern part of Argentina’s arid southern region of Patagonia, where rainfall has also increased.

But in other cases, the effects of climate change have been negative. Elsewhere in Argentina, rising temperatures have exposed the population to risks of diseases like malaria, dengue or yellow fever, for which the country is not prepared.

“In a tropical country, a shift in the mean temperature from 30 to 31 degrees celsius has less of an impact. But in this country, a one-degree modification in the minimum temperature – for example from 20 to 21 – means the isotherm (a line on a map of the earth’s surface connecting points having the same temperature at a given time) is shifting farther to the south,” explained Carcavalo.

In Brazil, for example, the population has defences against tropical diseases. But the same diseases would wreak havoc among Argentinians, who are used to cold winters in which no disease- carrying mosquitos survive.

The effects of climate change have been dramatically felt in storms characterised by hurricane-force winds caused by clashes of warm, wet air with cold, dry fronts, such as the two seen within a fortnight this year in the town of Guernica, in the central province of Buenos Aires.

According to the measurements taken by the country’s weather stations, in the past 40 years, the minimum mean temperature has risen between 0.6 and 1.3 degrees, which in some areas is enough to permit the survival of disease-carrying vectors like mosquitos.

Carcavalo’s explanation was backed by Lilian Corra, a member of the Argentinian Association of Doctors for the Environment and of the editorial committee of the Climate Change and Human Health magazine published in the Netherlands by experts from a number of countries.

Corra reported that researchers in Australia and the Netherlands, who are studying the phenomenon, have warned of the problems that arise from the lack of an “immune response memory” among the Argentinian population.

Reports by the United Nations Environment Programme (UNEP) have also mentioned “the case of Argentina.”

“Argentina was free of diseases like malaria, dengue and yellow fever, which means the population lacks immunity, because the human body has forgotten how to defend itself,” said Corra.

“The same thing is true of smallpox, which is why it has become a biological weapon today,” she added.

“On the other hand, the populations of Brazil, Bolivia and Paraguay can deal with such diseases, which are endemic in those areas. However, they present new outbreaks every year, farther and farther to the south – that is, closer and closer to the Argentinian border,” she said.

Corra noted that the Aedes Aegypti mosquito, which transmits dengue and yellow fever, and the malaria-carrying Anopheles mosquito cannot breed at temperatures below 20 degrees.

However, in the past few years, that natural barrier has disappeared in the northeastern Argentinian province of Misiones, on the border with Brazil, she pointed out.

Cases of yellow fever in monkeys have already been confirmed in Misiones. And cases of malaria, which in the past cropped up every two or three years, had become constant by 1996, when the latest statistics were gathered.

Dengue also reappeared in 1996, after disappearing from the country for 30 years. “The World Health Organisation had declared Argentina free of dengue 30 years ago, and now the disease is back,” said Carcavalo.

In its last few meetings, the Intergovernmental Panel on Climate Change has urged governments to avoid high-impact works in vulnerable areas like Argentina, where deforestation and the construction of dams have already altered rainfall patterns and led to severe flooding.

Corra and Carcavalo said that if the government assumed the problem as a priority issue for the nation, it could request credit to study the impact of climate change on health and make the necessary epidemiological projections.