Changes in temperature due to climate change over the next few decades will put considerable pressure on crop production in already vulnerable areas of sub-Saharan Africa, states a new study from Stanford University's Program on Food Security and the Environment published this week in Environmental Research Letters. The study found that average yields for five staple crops - maize, sorghum, millet, groundnuts, and cassava -will likely be harmed by warming without successful adaptation

"In all cases except cassava, we estimate a very high (95%) probability that damages would exceed 7%, and a low (5%) probability that they exceed 27%," said co-author David Lobell, an assistant professor of Environmental Earth System Science and center fellow at the Program on Food Security and the Environment, a joint program of the Freeman Spogli Institute for International Studies and Woods Institute for the Environment at Stanford.

The findings present a surprisingly robust picture of how weather affects yields in sub-Saharan Africa (SSA) and suggest there is a real threat of large near-term impacts in this food-insecure part of the world. SSA has the highest proportion of malnourished populations in the world, with one in three people chronically hungry.

"These are very resource scarce countries," noted lead author Wolfram Schlenker, assistant professor of economics at Columbia University, "and a reliable picture of what climate change will mean for crop yields can be very useful in allocating investments."

Panel dataset approach

Up to this point, the scientific basis for estimating production risks and prioritizing investments has been quite limited. "Many approaches have been limited by a lack of reliable data on such things as soil properties, historical agricultural data, and management practices," said Lobell. "This has not inspired a lot of confidence in the estimates, and has caused many to question some high-level statements about risks of climate change to Africa. The results presented in this study are not as disastrous as some have claimed, but they are big enough to suggest that major adaptations are needed in this region."

Schlenker and Lobell utilized a different approach than had been tried, by matching country-level yields (ton/ha) with various weather measurements for 1961-2002. By combining all the countries into a panel dataset, they were able to see a much clearer signal of weather than would be possible looking at data from individual countries.

"The observational approach enabled us to measure how farmers react to weather shocks given various, shared constraints such as credit markets and lack of required inputs," said Schlenker. "This is very difficult to do with a field trial approach."

Future research and investments

The authors emphasize that the results are not predictions of what will happen, but of what the potential stakes are if we don't take the threat seriously. Varieties with greater drought and heat tolerance, improved and expanded irrigation systems, rainwater harvesting technologies, disaster relief efforts, and insurance programs will likely all be needed to foster agricultural development and adaptation to warming.

"There is arguably little scope for substantial poverty reductions in SSA without large improvements in agricultural productivity," conclude the authors. "The findings presented here suggest that this challenge will get even more difficult in a warming climate. Rather than a cause for despair, we view this as an added incentive for serious, immediate, and sustained investments in agricultural productivity in SSA."

This work was supported by a grant from the Rockefeller Foundation. The Program on Food Security and the Environment is jointly run by the Woods Institute for the Environment and the Freeman Spogli Institute for International Studies at Stanford.

Jenny Aker an Assistant Professor in the Economics Department and Fletcher School of Law and Diplomacy, Tufts University, provided an overview of the welfare impacts of mobile technologies and how current research is testing our assumptions about the benefits of mobile phones for individuals in developing countries.

Mobile phones are used by some of the poorest people in the world; even at the country ranked 160 in the UN's Human Development Index, levels of adoption of mobile phones are at 50%. There are few systematic studies looking at why people adopt mobile technology, but those that exist suggest there are correlations with higher income levels, trading professions and an urban location. Mobile phone coverage across Africa is now extensive. Research shows that roll out by mobile phone companies is determined by factors including the size of population, the costs associated with terrain, quality of road access and the operating environment (whether there exists a competitive liberalized market).

Identifying the positive impact of mobiles can be difficult because they have so many uses, making assessment of costs and benefits problematic. Mobiles are also only pseudo private goods since they are often shared and benefits extend beyond the owner.  Despite these difficulties, a number of researchers have demonstrated the impact of mobile phones in the developing world. Robert Jensen's paper found that the introduction of mobiles into the fishing industry in Kerala, India resulted in reduced price discrepancies and significant welfare benefits in the form of increased profits for fishermen and reduced waste. Similarly, Jenny's own study of grain markets in Niger found that the use of mobile phones reduced price discrepancy and enhanced welfare through increased trader profits and reduced average consumer prices.

As well as these externalities from the IT sector, we are also seeing deliberate attempts to harness the potential of mobile phones, from private sector services (e.g. the provision of mobile money transfers such as M-Pesa) to non-profit development projects using mobiles in diverse contexts including health, governance and market information. Jenny is currently working on a project that will examine how mobiles can improve literacy in Niger. A pilot of Project ABC over the next three years will assess how access to mobile phones can complement traditional literacy lessons by giving people the chance to practice their literacy skills via SMS. Early results suggest significantly higher performance in literacy testing by groups using mobile phones.

If mobiles have genuine welfare impacts then ensuring access becomes a key policy concern. Jenny highlighted the importance of continuing liberalization of telecoms markets in Africa, maintaining fair and transparent legislation and reconsidering ICT taxes (in some countries mobiles are taxed as a luxury good). But while mobiles can enhance the delivery of and access to resources and information, we should be wary of viewing them as a development panacea since they cannot replace basic infrastructure investments such as power and roads.