/CORRECTED REPEAT/ENVIRONMENT: Climate Change Spurs Lightning Strikes and Death

By Mario Osava Reprint | | Print |

Mario Osava

RIO DE JANEIRO, Apr 3 2001 (IPS) - Global warming has prompted an increase in electrical storms, especially in tropical regions, killing more people and causing greater economic losses as the Earth’s temperatures rise, warn scientists in Brazil.

A study by Osmar Pinto Junior, coordinator of the Atmospheric Electricity Group (ELAT) at the National Institute of Atmospheric Research in Brazil, took on a dramatic edge this year as a result of the increased lightning storm activity in the country’s most populous region.

Anderson Carlos Acosta, 15, died last Wednesday in Limeira, 150 km from Sao Paulo, from complications involving burns over his entire left leg caused by a lightning strike.

Acosta was lightning victim number 51 so far this year in Brazil, according to ELAT data.

But the research team’s statistics are probably incomplete due to the lack of information about unreported cases, especially in the country’s interior, said Pinto Junior, who estimates that the true total could be as much as 50 percent higher.

The number of human deaths caused by electrical storms in Brazil averages 100 to 150 annually, according to the latest studies. The exceptional year in the last decade was 1996, with 167 deaths, based on Ministry of Health reports.

The high average of fatal lightning incidents threatens to repeat itself this year as a result of the high temperatures recorded over the last few months – the southern hemisphere summer – in the country’s south and central regions.

The heat is attributed to the climatic phenomenon known as La Niña, which originates in the Pacific Ocean and tends to alter the climate throughout the Americas.

The occurrence of lightning in Sao Paulo state has doubled this year compared to last, reflecting an excess of electricity in the air, while energy shortages are affecting the nation’s centre and northeast because of a drought that began last year and has left the reservoirs of hydroelectric dams well below their normal levels.

Lightning discharges, however, have been unevenly distributed. In the metropolitan region of Sao Paulo, where there is a higher concentration of people and industry, there were 40,000 strikes recorded last summer, compared to 15,000 the previous summer.

In the region around Valle del Rio Paraíba, which is also highly industrialised, lightning strikes increased five-fold, reaching 50,000 this year, according to ELAT measurements.

Higher demographic and industrial density explain the increase, as they create “thermal islands” in urban areas, which are fomented by air pollution and large cement-covered surfaces, such as streets and sidewalks, Pinto Junior pointed out.

The number of lightning strikes worldwide will double this century, he said, if the Earth’s average temperature rises by four or five degrees as has been widely predicted.

It is essential to adopt measures to prevent deaths and material damages from increasing in the same proportion, stated the scientist.

Material losses are for the most part indirect, such as the unexpected interruption in electrical energy supplies, which can affect industrial output and even ruin machinery and equipment.

Lightning is blamed for nearly 70 percent of the power outages suffered in Brazil, where officials estimate that the national economy loses 100 to 200 million dollars annually as a result.

One of the ways to prevent deaths, in addition to the collective protection provided by lightning rods and other elements that conduct electrical discharge into the ground, is to avoid contact with cables and electrical apparatuses, said Iara Cardoso de Almeida, an ELAT researcher.

Public awareness of the risks and of prevention can reduce the number of victims, she affirmed. In the United States, for example, in the years when data was first collected on the subject, some 200 people died annually from lightning strikes, but now deaths do not surpass 80 a year.

The decline in mortality in the United States from this cause is attributed to the exodus from rural areas, but also to preventive measures, many of which are implemented on an individual basis.

Brazil has also undergone rapid urbanisation of its population over the last 50 years, but the mortality rate from lightning remains high because of the increasing number of electrical storms, Pinto Junior stressed.

Brazilians living in larger cities believe they are protected by lightning conductors so they do not attempt to avoid unsafe situations, say the experts. The deaths that have occurred so far this year in the urban environment – at least five in Sao Paulo and two in nearby Campinas – serve as a warning that residents are still at risk.

Heat and humidity make Brazil’s Amazon region another centre of lightning strikes – a fact that raised the costs of installing the National Surveillance System, which the government is developing there to collect data, control air traffic and pursue perpetrators of illegal activities.

The extremely frequent electrical discharges meant expanding the grounding mechanisms and setting up installations on unfavourable terrain, with many unforeseen costs involved, explained Luis Miranda, one of the professors from the Federal University of Rio de Janeiro’s engineering programme involved in the works.