[This is the second in a four-part series of guest posts by first year students in Columbia's Sustainable Development program]
The Global Food System and Water Crisis: 10 Science Papers from the Past Year
To get caught up on the latest research on the global food system and water crisis we did a survey of the must-read articles from the last twelve months. The requirements to make our list were simple. First, the article had to be from the Research Articles or Reports sections of Science or the Review, Articles, or Letters sections of Nature published between May 2011 and April 2012. Then we picked the ones that we thought would have the most significant impact on humans, were the most immediate or critical concerns, or were the most unique solutions to the current crises faced. And here they are…
Foley et al. offer a framework to think about the dilemma of future food security and environmental sustainability on a global scale. They argue that a new agricultural system must deliver more human value, to those who need it most, with the least environmental harm. They outlined four food security goals: increasing total agricultural production, increasing the supply of food (recognizing that agricultural yields do not always equate with food access), improving the distribution and access to food, and increasing the resilience of the whole food system, and four key environmental goals that agriculture must also meet: reducing greenhouse gas emissions from agriculture and land use, reducing biodiversity loss, phasing out unsustainable water withdrawals, and curtailing air and water pollution from agriculture. In the paper, they summarized and analyzed the potential strengths and weaknesses of four proposed strategies: stop expanding agriculture, close yield gaps, increase agricultural resource efficiency and increase food delivery by shifting diets and reducing waste. This article was a great comprehensive framework for looking at food and water issues.
A major theme throughout the articles was measuring the impacts of climate change on agriculture. What we found ranged from new findings on how plant flowering is timed and how these pathways are already changing in response to small differences in temperature (Kumar et al.), to an article studying molecular and genetic bases for climate adaption in a plant genome (Arabidopsis thaliana) (Hancock et al.), to how in a CO2-enriched world semi-arid grasslands will have improved water use efficiency, so both soil water content and productivity in the semi-arid grassland may be higher than previously expected (Morgan et al.).
Lobell et al. did an econometric analysis of climate trends on crop production (based on the crops that account for 75% of the calories humans consume) for all countries in the world. They found negative impacts globally for maize and wheat production and insignificant impacts on rice and soybean under climate trends compared to a counterfactual without climate trends. Since we don’t know how plants will react to future climate changes this article serves as an initial reference for how future temperature trends may impact crop output on the global scale.
The issue of the impact of food production on biodiversity is discussed in Phalan et al. They compare land sharing (integration of biodiversity conservation and food production on the same land) with land sparing (separating land for conservation from land for crops, with high-yield farming) to see which would do the least harm to biodiversity. The study compared crop yields and densities of bird and tree species across gradients of agricultural intensity in southwest Ghana and northern India. The results suggest that in both countries land sparing would be the optimal strategy.
Another perspective we thought was important to include is the threat posed by increased fungal emerging infectious diseases. Fisher et al. calculate that “even low-level persistent disease leads to losses that, if mitigated, would be sufficient to feed 8.5% of the 7 billion humans alive in 2011. If severe epidemics in all five crops were to occur simultaneously, this would leave food sufficient for only 39% of the world’s population, but the probability of such an event occurring is very low indeed” (191). Global trade and transportation and anthropogenic mixing has and will continue to lead to more harmful fungi strains that jeopardize food security, unless we improve biosecurity the authors argue.
In both covered journals there were surprisingly few papers dealing with the global water issue. The two most relevant papers in our view deal with reactive Nitrogen as a major source of water pollution, and resilience of water system to environmental disturbance. Holtgrieve et al. studied the accumulation and ecological effects of reactive nitrogen (Nr) using sediments in lakes with minimum anthropogenic impact. The study indicates that atmospheric Nr deposition in remote areas (which has been increasing since preindustrial times), are likely to permeate the biosphere at the hemispheric scale, despite its relatively low rates currently. Davidson et al. focused on interactions between global climate, land use, fire, hydrology, ecology and humans in the Amazon basin. The paper indicates that although the basin-wide impacts of land use and drought may not yet surpass the magnitude of natural variability of hydrologic and biogeochemical cycles, there are some signs of a transition to a disturbance-dominated regime. These signs include changing energy and water cycles in the southern and eastern portions of the Amazon basin.
That concludes our list. We welcome any comments or recommendations for other articles that we may have missed.
Davidson, E. A., de Araújo, A. C., Artaxo, P., Balch, J. K., Brown, I. F., Bustamante, M. M. C., Coe, M. T., et al. (2012). The Amazon basin in transition. Nature, 481(7381), 321–328. Nature Publishing Group. doi:10.1038/nature10717 http://dx.doi.org/10.1038/nature10717
Fisher, M. C., Henk, D. A., Briggs, C. J., Brownstein, J. S., Madoff, L. C., McCraw, S. L., & Gurr, S. J. (2012). Emerging fungal threats to animal, plant and ecosystem health. Nature, 484(7393), 186–194. Nature Publishing Group. doi:10.1038/nature10947 http://dx.doi.org/10.1038/nature10947
Foley, J. A., Ramankutty, N., Brauman, K. A., Cassidy, E. S., Gerber, J. S., Johnston, M., Mueller, N. D., et al. (2011). Solutions for a cultivated planet. Nature, 478(7369), 337–342. Nature Publishing Group. doi:10.1038/nature10452 http://dx.doi.org/10.1038/nature10452
Hancock, A. M., Brachi, B., Faure, N., Horton, M. W., Jarymowycz, L. B., Sperone, F. G., Toomajian, C., et al. (2011). Adaptation to Climate Across the Arabidopsis thaliana Genome. Science, 334(6052), 83–86. http://www.sciencemag.org/content/334/6052/83.abstract
Holtgrieve, G. W., Schindler, D. E., Hobbs, W. O., Leavitt, P. R., Ward, E. J., Bunting, L., Chen, G., et al. (2011). A Coherent Signature of Anthropogenic Nitrogen Deposition to Remote Watersheds of the Northern Hemisphere. Science, 334(6062), 1545–1548. http://www.sciencemag.org/content/334/6062/1545.abstract
Kumar, S. V., Lucyshyn, D., Jaeger, K. E., Alós, E., Alvey, E., Harberd, N. P., & Wigge, P. A. (2012). Transcription factor PIF4 controls the thermosensory activation of flowering. Nature, 484(7393), 242–245. Nature Publishing Group. doi:10.1038/nature10928 http://dx.doi.org/10.1038/nature10928
Lobell, D. B., Schlenker, W., & Costa-Roberts, J. (2011). Climate Trends and Global Crop Production Since 1980. Science, 333(6042), 616–620. http://www.sciencemag.org/content/333/6042/616.abstract
Morgan, J. A., LeCain, D. R., Pendall, E., Blumenthal, D. M., Kimball, B. A., Carrillo, Y., Williams, D. G., et al. (2011). C4 grasses prosper as carbon dioxide eliminates desiccation in warmed semi-arid grassland. Nature, 476(7359), 202–205. Nature Publishing Group. doi:10.1038/nature10274
Phalan, B., Onial, M., Balmford, A., & Green, R. E. (2011). Reconciling Food Production and Biodiversity Conservation: Land Sharing and Land Sparing Compared. Science, 333(6047), 1289–1291.
Shindell, D., Kuylenstierna, J. C. I., Vignati, E., van Dingenen, R., Amann, M., Klimont, Z., Anenberg, S. C., et al. (2012). Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security. Science, 335(6065), 183–189. http://www.sciencemag.org/content/335/6065/183.abstract