The African continent, as well as many developing nations in Asia and Latin America, is dependent on both wood and charcoal for cooking and heating homes. In 2000, nearly 470 million tons of wood were consumed in homes in sub-Saharan Africa in the form of firewood and charcoal. This is more wood per capita than is used in any other region in the world. However, more than 1.6 million people, primarily women and children, die prematurely each year worldwide (400,000 in sub-Saharan Africa) from respiratory diseases caused by the pollution from such fires, according to previous studies by the researchers.
The current study, published in the April 1 issue of the journal Science, concludes that by 2030, smoke from wood fires used for cooking will cause about 10 million premature deaths among women and children in Africa. By 2050, according to the report, smoke from cooking fires will release about 7 billion tons of carbon in the form of greenhouse gases to the environment. That's about 6 percent of the total expected greenhouse gases from the continent.
The researchers conclude that "helping African nations make the transition to clean charcoal without drastically increasing pollution and decimating tropical forests would be an excellent way to help achieve several of the United Nations' 'millennium development goals' at the same time. It also presents an opportunity for the developed world to invest in the African continent, as many promised at the January meeting of the World Economic Forum in Davos, Switzerland, and as promoted by British Prime Minister Tony Blair at the recent G-8 summit."
"If the rapid urbanization continues - and all signs indicate th at it will - then the trend is going to be toward greater charcoal use in Africa. It's the most affordable source of household energy," said Robert Bailis, graduate student at the Energy and Resources Group at UC Berkeley and lead author of the paper. But whichever path Africa takes, he added, "we are saying there are multiple consequences, including preventable deaths and pollution emissions. Decisions made now or in the near future are going to have large effects on health and environmental outcomes in the distant future."
The authors assessed multiple strategies to reduce mortality as well as greenhouse gas emissions from household fuel sources. They gathered a large database of current fuel use in African nations. Using this as a baseline, they defined multiple scenarios for future fuel use by varying the mix of wood, charcoal and petroleum-based fuels used in households and improving the sustainability of wood harvesting and charcoal production techniques.
The best situation in Africa would be to transition from biomass fuels to petroleum-based fossil fuels such as kerosene and liquid propane gas, the authors noted, which could prevent 1.3 to 3.7 million premature deaths, depending on the speed of transition. The authors argue, however, that current economic conditions and energy infrastructure in Africa make petroleum-based fossil fuels an unlikely option.
"If you switch everyone off the dirtiest fuels to burning clean fossil fuels, you get the biggest health benefit," acknowledged Daniel Kammen, the Class of 1935 Distinguished Chair of Energy at UC Berkeley and a co-author of the paper. "But the economic cost to most African nations - collectively the poorest region of the globe - of that switch is impossible."
Majid Ezzati, assistant professor of international health at the Harvard School of Public Health and a co-author of the paper, added that "it's also a lot easier to disseminate charcoal in large scale than fossil fuels, because there is a well developed market and you don't need expensive infrastructure like refineries and processing. So, while fossil fuels are in fact better for health and better for climate, they are more expensive and a lot harder to get out."
Charcoal burns cleaner and produces less indoor pollution than wood, but the current inefficient production method in Africa is one of the most polluting for the global environment and potentially destructive to African forests. The researchers' analysis shows that charcoal can provide comparable health benefits of 1 to 2.8 million avoided deaths. However, scenarios that forecast large shifts to charcoal without improvements in harvesting and production would lead to severe increases in greenhouse gas emissions, they said, with over 15 billion tons of carbon released into the atmosphere by 2050.
"Most charcoal is produced in Africa by one or two guys going out in the woods, almost always without a permit and on somebody else's land, cutting down a tree or two, chopping it up, lighting it, covering it with dirt, and then hovering around it for two to four days while it becomes charcoal," Kammen said. "It's no surprise it's not generally a high-efficiency operation."
The authors found that by creating the technological and policy tools for transitioning to higher efficiency charcoal production technologies and sustainable harvesting, like those used today in countries such as Brazil and Thailand, greenhouse gas emissions can be reduced by 45 percent in a gradual transition scenario, and by 66 percent in a rapid transition case.
"This study shows that choosing energy technologies with an eye toward improving health and quality of life in one of the world's most impoverished areas offers us opportunity to significantly reduce premature deaths, especially among women and children," said Ezzati.