Can agroforestry provide a win-win for climate mitigation and adaptation in Africa?
The challenge of increasing food production in Africa to meet the needs of a growing population is immense, especially when this has to be achieved on soils that are already depleted of their fertility, amid changes in climate and in ways that reduce greenhouse gas emissions or perhaps even store carbon.
In a special issue of Current Opinion in Environmental Sustainability due to be released in February 2014 to coincide with the 3rd World Congress on Agroforestry in Delhi, India, scientists claim that agroforestry systems can help meet both mitigation and adaptation objectives while remaining relevant to the livelihoods of poor smallholder farmers in Africa.
The way forward, according to Cheikh Mbow, Senior Scientist on Climate Change and Development with the World Agroforestry and lead author of the article, is not through focusing on the climate change mitigation potential of agroforestry (i.e. improving carbon sequestration and reducing emissions) but on the ability of agroforestry to boost food production and provide climate adaptation benefits.
“There’s plenty of evidence of how agroforestry systems can help farmers build resilience to changes in climate and increase crop yields and incomes while at the same time storing carbon,” outlines Mbow.
The article provides an overview of the benefits provided to smallholder farmers from agroforestry, including assets and income such as timber, fuel wood, fruits for added nutrition, animal fodder and medicinal products.
“Farm profitability has been shown to increase through agroforestry where farming systems are diversified (with trees providing new products for sale or consumption) or improved (with trees protecting against wind and water erosion or providing organic fertilizer),” says Mbow.
Properly managed agroforestry systems can also play a crucial role in helping farmers adapt and build resilience to uncertain climates. Trees can provide a buffer against climatic extremes that impact crop growth. They can enhance understory growth and improve water use efficiency. Trees have also been shown to increase rainfall utilization compared to annual cropping systems. Trees are known to have a direct impact on local and regional rainfall patterns, so they also have considerable potential to alleviate drought in parts of Africa.
Declining soil fertility is a serious issue for agriculture in Africa. The article explains how agroforestry can increase soil fertility through increased soil organic matter and nitrogen fixation by leguminous trees.
But it’s the ability of trees to store carbon that has led to increased attention being paid to agroforestry in Africa in recent years for its potential in climate change mitigation.
Agroforestry systems in Africa constitute the third largest carbon sink after primary forests and long term fallows. But the carbon sequestration potential of agroforestry depends on which tree species are selected and how they are managed as well as soil characteristics, topography, rainfall and agricultural practices.
As Mbow and colleagues outline in their paper, climate change mitigation in Africa to date has largely focused on reforestation and forest protection. This has often conflicted with the need to expand agricultural production to feed the continent’s growing population. But this needn’t be the case, says Mbow, as agroforestry may be able to deliver both on increasing tree cover to store carbon while also enhancing agricultural productivity.
Studies have shown that there is enormous potential to increase tree cover on farms in Africa without impacting on production, and in many cases it can increase yields. There are an estimated 1,550 million hectares in Africa considered suitable for some form of agroforestry.
“The key thing to realize is that it is impossible to disassociate the mitigation and adaption benefits of trees,” explains Mbow. “Carbon storage alone won’t motivate countries and farmers to engage in agroforestry, but social and economic benefits through increased crop yields and a supply of additional products for consumption or markets will.”
“Carbon sequestration must be a co-benefit in Africa to strategies that support sustainable livelihoods and adapt to climate change, not the other way around.”
Mbow says agroforestry has to attract more attention in global agendas not just for its mitigation potential but because it has numerous positive social and environmental impacts, not least of which is a pathway out of poverty and towards food security for poor African farmers.
Download the full article:
Mbow C, Smith P, Skole D, Duguma L, Bustamante M. (2014). Achieving mitigation and adaptation to climate change through sustainable agroforestry practices in Africa. . Current Opinion in Environmental Sustainability 6: 8-14.
This article appears in a special issue of the journal Current Opinion in Environmental Sustainability on the theme ‘Sustainability challenges.’ The full special issue is available Open Access at http://www.sciencedirect.com/science/journal/18773435/6/supp/C
The issue will be launched during the World Congress on Agroforestry in Delhi, India in February2014.