Africa will win environmental and health benefits if it stops burning wood.
A shift from burning wood to burning charcoal in African households could save millions of lives and substantially reduce emissions of greenhouse gases, say US researchers.
If current trends in fuel use in sub-Saharan Africa continue, the number of premature deaths among women and young children exposed to wood smoke from stoves will reach nearly 10 million by 2030, from about 400,000 in 2000. What's more, cooking fires will pump 6.7 billion tonnes of carbon into the atmosphere as greenhouse gases in the next 45 years, the researchers calculate.
“You don't often come across a situation where using existing technology would make such a big difference. Dan Kammen , University of California Berkeley”
"These numbers are absolutely shocking," says John Spengler, an environmental-health expert at Harvard University in Cambridge, Massachusetts. "We have to pay attention to this."
The research team, led by Dan Kammen of the University of California, Berkeley, predicted the health and environmental effects of introducing new fuel-use and land-management strategies, either gradually (over the next 50 years) or rapidly (within 10 to 15 years).
Kerosene or charcoal
A switch from burning wood to burning petroleum-based fossil fuels such as kerosene would reduce indoor air pollution by at least 90%, and prevent as many as 3.7 million deaths from respiratory illness, depending on how quickly the transition was made, the researchers report in this week's Science1.
Although this seems like a quick and easy fix, development of the necessary fuel-distribution infrastructure, given the continent's difficult economic situation, make this option "totally unaffordable for Africa", says Kammen.
A more feasible solution with similar health and environmental benefits would be to shift from burning wood to burning charcoal, the researchers suggest. Although charcoal is the leading urban fuel in Africa and releases less indoor particulate matter when burned than wood, its use does not garner much support from policy-makers or environmentalists.
"Charcoal production is associated with deforestation," explains Kammen's colleague Rob Bailis. "And as it is currently practised it is a dirty process." Charcoal is typically made by covering a stack of wood with dirt and allowing it to smoulder for three to seven days. This process is inefficient and pollutes the air.
However, the researchers' model predicts that a large-scale shift to burning charcoal, combined with sustainable forest management and use of more efficient charcoal-production technologies, would avert some 3 million premature deaths and reduce greenhouse-gas emissions by 65% if implemented rapidly. Even if adopted gradually over 50 years, the move would ultimately delay 1 million deaths and cut greenhouse-gas emissions by 45%, relative to simply carrying on as usual.
Furthermore, the technologies to make charcoal more cleanly and efficiently, such as permanent brick or steel kilns with systems to control emissions, could be easily implemented. "You don't often come across a situation where existing technology would make such a big difference," says Kammen.
Although the authors do not outline specific policy recommendations, their findings address several of the UN Millennium Development Goals, including reducing child mortality and ensuring environmental sustainability.
"The decisions made today are going to determine whether we reach those outcomes," says Bailis. "Our findings are meant to encourage as much dialogue as possible and remove some of the tarnish associated with the use of charcoal."
BailisR., EzzatiM. & KammenD.Science, 308. 98 - 103 (2005).
University of California Berkeley