Click for Stanford Login
For local admin account, login below.
In this project, we seek to improve quantitative understanding of price spikes in general and the potential effects of climate change on these spikes in particular. The project is divided into five steps. Part A will consider the relationship between weather outcomes and yields for the four major staple crops: corn, soybeans, wheat and rice. Part B establishes how weather distributions are predicted to change in various general circulation models.Part C combines the crop yield response function of part A with the predicted changes in weather outcomes to derive a distribution of yield outcomes. Specifically, we will consider how (1) yield variability increases with higher average temperatures because of the nonlinear response of yield to temperature; (2) yield variability increases with potential increased climate variability and frequency of extreme weather events; (3) bad weather events could become more or less correlated between key regions and thereby affect the extent to which idiosyncratic weather shocks may no longer average out, influencing aggregate yield variability; (4) production could become more or less concentrated in particular regions and thus again influence the variability of aggregate yield outcomes.Part D considers estimation of fundamental demand, supply and storage elasticities of agricultural commodities using random exogenous yield shocks as an instrument. These elasticities are required to translate yield distributions from part C into price distributions. Part E will use results from parts C and D to simulate the effects of changing climatic conditions on food prices. We will examine how the increased supply variability will affect optimal storage behavior.More frequent price spikes give an added incentive to accumulate inventories, thereby dampening the predicted increase in price spikes. Similarly, continued expansion of irrigated agriculture can make yields less variable. On the other hand, some government policies, like export restrictions have the potential to increase price variability, and may also affect storage behavior.
Adaptation of vulnerable areas to climate change is---and will continue to be---an important subject of negotiations taking place in several international forums, including the United Nations Framework Convention on Climate Change; the Major Economies negotiations; and the G-8 talks. Ideally, adaptation assistance to any given nation would be commensurate with the social and economic impacts of future climate change and the cost of the required adaptation measures. Instead, neither is known. Climatic changes themselves are only projected in broad strokes: important details at the regional and sub-seasonal scale---such as the changes in frequency of monsoon breaks in the Niger River basin, to make just one example---are not simulated directly by current climate models. Moreover, determining the economic impact of a given climate scenario is challenging, as is assessing the cost and efficacy of adaptation scenarios, as demonstrated by the controversy that followed the Stern review.Yet, as imperfect and incomplete as it is, the output of climate and economic models must inform negotiations for international adaptation funds---if those are not to be solely the result of political expediency. The aim of this project is to bring together climate scientists, economists, and law scholars to identify how to best achieve the goal of bringing climate and economic modeling results to bear on these negotiations. In particular, we want to identify (i) what is the most useful information that can be delivered to negotiators by state-of-the-art climatic and economic models, (ii) how that information can be most effectively presented, and (iii) how measures of uncertainty can be brought into the negotiation process as additional, valuable information.The proposed project is organized around three main questions that address (i) the nature of the information needed for the best allocation of resources, (ii) the form in which such information should be framed in order for it to be most comprehensible and useful to negotiators, and (iii) the extent to which uncertainty in the projections is now used to discount climate impact information and how instead uncertainty estimates can be reformulated as valuable information regarding the range and likelihood of possible outcomes and incorporated in the negotiation process.
Agricultural productivity is highly dependent on climate variability and is thus susceptible to future changes including temperature extremes and drought. The latter is expected to increase in frequency regionally over this century. However, the uncertainty in projections of drought and its impacts on agriculture is high due to emission scenarios, climate model differences, uncertainty in initial/boundary conditions, and translation to regional scales. Climate models are unanimous in projecting future warming but differ in the magnitude and even sign of regional precipitation changes. They also differ in terms of extremes of temperature, precipitation and other meteorology. When projecting future impacts on crop productivity, these uncertainties are compounded because current crop models often use simplified treatments of climate response and do not include comprehensive treatments of water availability. Therefore, projections of regional climate change, variability and its impacts on water availability and agriculture are highly uncertain and reduction of uncertainties requires attention to all levels in the climate-water-agriculture continuum.Rationale: Given the uncertainties in future agricultural production and the complex relationships between climate, hydrology and crop development, there is pressing need to make improved estimates of future changes in climate change and crop yields. We propose to evaluate the uncertainties in estimates of future changes in climate, water availability and agricultural production, and make improved estimates by incorporating state of the art knowledge of the relationships between climate, hydrology and agriculture into modeling and downscaling. This has ramifications for disaster preparedness and mitigation, policy making and the political response to climate change, and intersects with fundamental science questions about climate change, extremes and hydrologic cycle intensification. It is central to the mission of the Climate Program Office’s MAPP program to “enhance the Nation’s capability to predict variability and changes of the Earth’s System” and directly addresses its priorities to evaluate and reduce uncertainties in climate projections. This work will leverage from the PIs’ experience and ongoing activities in large-scale climate analysis and hydrologic modeling, particularly in changes in drought historically and under future climates, and agricultural modeling and relationships between climate and crop productivity.Summary of work to be completed:Quantify the relationships between hydroclimate variables and the implications for water, drought and agriculture based on observational data. Evaluate sensitivities of hydrologic and crop models to changes in climate and drought. Differences in climate variability, land-atmosphere coupling and hydrologic persistence will lead to differences in key metrics of water and agriculture which will form the basis for evaluation of the uncertainties in future projections. Evaluate current climate models in how they replicate these observed relationships using the CMIP5 long-term and decadal predictions. Estimate uncertainties in future projections of climate, drought and agriculture using a cascade of climate, downscaling, hydrologic and crop models with strategic sampling to decompose sources of uncertainty. Implement a set of methods to reduce uncertainties in future projections based on observational constraints including merging of climate model predictions, bias correction and scaling of climate model output, and improvements to impact models.
FSE's previous Rockefeller project on "Prioritizing Investments in Food Security under a Changing Climate" pursued several research directions in an effort to better characterize the risks that climate change poses to agriculture in Africa. Among the lessons from the project were that climate change poses a substantial impediment to agricultural progress in Africa, that maize and Southern Africa are particularly vulnerable, and that inadequate soil moisture can substantially aggravate the effects of heat.Although several questions remain on the question of risks and adaptation needs, we are gradually shifting our research program to evaluate priorities from the perspective of adaptation opportunities. What works and what doesn't? Or more specifically, what are the most effective ways to deal with the most serious threats that climate change poses? And given the type and scale of current efforts at adaptation, is Africa on a trajectory to effectively adapt to climate change?A key lesson from prior work is that climate change is already underway and having non-trivial effects on agriculture, even today. From a research perspective, this increases the urgency of finding effective adaptations but also provides an opportunity to learn from ongoing attempts to adapt production systems.The research project includes four main components:Evaluating the adaptation potential for new crop varieties.Evaluating the adaptation potential of small-scale irrigation.Evaluating a suite of adaptation options in the Sahel.Characterizing ongoing and proposed adaptation activities.
The project is supported under the NSF Science, Engineering and Education for Sustainability Fellows (SEES Fellows) program, with the goal of helping to enable discoveries needed to inform actions that lead to environmental, energy and societal sustainability while creating the necessary workforce to address these challenges. Sustainability science is an emerging field that addresses the challenges of meeting human needs without harm to the environment, and without sacrificing the ability of future generations to meet their needs. A strong scientific workforce requires individuals educated and trained in interdisciplinary research and thinking, especially in the area of sustainability science. With the SEES Fellowship support, this project will enable a promising early career researcher to establish herself in an independent research career related to sustainability. This project focuses on food sustainability and security on a global scale. The partnerships built into this project will give the Fellow significant inter-disciplinary training (adding the components of randomized controlled trials and crop modeling) beyond the scope of her current expertise. This is particularly important since her goal is to become a sustainability scientist who combines methods and tools from the natural and social sciences to understand how humans are impacted by and adapt to environmental change. Specifically, the Fellow will participate in an interdisciplinary institutes (Center on Food Security and the Environment at Stanford, and Center for Effective Global Action at UC Berkeley). Also, at Stanford University, the Fellow will gain teaching and mentoring experience.Climate change is predicted to negatively impact agricultural communities and food security across the globe, with models estimating up to a 40% reduction in the yield of some crops by the end of the century. This is particularly problematic for wheat, which is a major staple crop (providing 20% of daily calories) that is already facing declining yields due to warming temperatures. Previous studies have shown that autonomous adaptation strategies (e.g. increasing irrigation, shifting planting date) are not enough to mitigate the negative impacts of warming, and planned adaptation strategies that introduce heat-tolerant wheat varieties are needed to sustainably bolster yields and food security in the face of climate change. Interdisciplinary research is necessary to (1) identify the most effective ways to introduce these new technologies to vulnerable communities, and (2) assess whether the predicted yield benefits of these crops are realized in the field where farmers may deviate from ideal management practices. This study uses randomized controlled trials from development economics to evaluate introduction strategies, remote sensing to quantify if new heat-tolerant wheat varieties provide yield benefits in the field, and process-based crop models to assess whether these new varieties provide predicted yield benefits in future warming scenarios. Understanding the effectiveness of information transfer is particularly important for heat-tolerant crops because, unlike high-yielding varieties introduced during the Green Revolution, heat-tolerant crops may not provide immediate benefits and only produce higher yields in unseasonably warm years. Thus, the adoption and diffusion of this technology may depend purely on whether farmers trust and receive accurate information about possible future benefits. This study is one of the first to examine the most effective ways to introduce new crops that mitigate against climate variability and future climate risk, which is necessary to sustainably enhance food security in the face of climate change.
A team led by FSE fellow David Lobell has found a valuable, untapped resource in historical data from crop yield trials conducted across sub-Saharan Africa. Combined with weather records, they show that yield losses would occur across 65 percent of maize-growing areas from a temperature rise of a single degree Celsius, even with sufficient water.Over much of the world, the growing season of 2050 will probably be warmer than the hottest of recent years, with more variable rainfall. If we continue to grow the same crops in the same way, climate change will contribute to yield declines in many places. With potentially less food to feed more people, we have no choice but to adapt agriculture to the new conditions. New approaches are needed to accelerate understanding of climate impacts on crop yields, particularly in tropical regions. This project is studying the potential effects of climate change on agriculture and adaptations options in African agriculture. The work will seek to assess climate threats to staple food crops at a country level, quantify the sources of uncertainty inherent in these assessments, and determine what implications shifts in crop climates have for agricultural adaptation and genetic resources preservation - with the end goal of helping prioritize investments in agricultural development and food security under a changing climate.
Report accessibility issues
© Stanford University, Stanford, California 94305. Copyright Complaints