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.

Global Voices was inspired by an incident in 2004, when a friend reading a New York Times article about Cameroon's elections posed the question: is there anyone in Cameroon blogging about this? Along with his colleague, former CNN Beijing journalist Rebecca MacKinnon, Ethan convened a group of bloggers from the developing world at Harvard. What came out strongly from these discussions was a desire for participants to be able to read each others' blogs. What started as Rebecca and Ethan each summarizing a couple of hundred blogs daily has grown into the Global Voices website, which uses a network of 400 editors to filter, translate and provide context to global blogs, making them accessible to readers around the world.

Since 2004, there have been some major changes to the context in which Global Voices operates. The organization has tried to respond to each of these:

• There has been massive expansion in internet access across the developing world, but rarely beyond the middle class and educated. Rising Voices allows media organizations from developing countries to apply for small grants to help them use digital media in their communities. A number of great success stories coming out of this initiative have demonstrated that it is possible to get traction for citizen media, even in very low resource communities.
• The digital space has emerged as a political space. This has prompted far greater levels of censorship. Global Voices Advocacy works to highlight cases of individuals arrested for involvement in citizen journalism and attempts to keep these stories live. It also works to document censorship of publishing platforms and to provide spaces where people can blog anonymously.
• In 2004, almost all blogging was in English. Now the majority of people are blogging in their own languages, about local issues. Translation therefore becomes a greater challenge. ProjectLinguauses volunteer translators to amplifyGlobal Voicesin many languages other than English.

Ethan suggested three possible theories about what we are seeing in the growth of social media:

• Social media will be the natural organizing tool for a new generation.
• Social media is an asymmetric tool - it is what you use when the tools of more effective mainstream media are not available to you.
• Social media is a story in itself - it can draw attention to a story that might otherwise not be picked up.

Crisis situations such as the protests in Iran and the Haitian earthquake have started to legitimize the use of social media by mainstream media outlets, blurring the boundaries between professional and citizen reporting. And some of the key challenges associated with access and language barriers are beginning to be addressed. But the problem of global attention span will be hardest to solve. So many situations never receive coverage and for those that do, the media cycle rarely allows them to stay in the spotlight beyond a few weeks. We have developed long standing bad habits in our understanding of what constitutes news. Social media has dramatically changed who is able to speak; but will it change how we choose to listen? This remains a major challenge.