Although China and the United States are the two largest emitters of greenhouse gases, China’s emissions on a per capita basis are significantly lower than those of the U.S.: in 2005, per capita emissions in China were 5.5 metric tons—much less than the U.S. (23.5 metric tons per capita), and also lower than the world average of 7.03 metric tons. China’s total GHG emissions were 7,234.3 million tons of CO2 equivalent (tCO2e) in 2005, 15.4 percent of which came from the agricultural sector. By comparison, total U.S.
Improving crop yields in major agricultural regions is one of the foremost scientific challenges for the next few decades. In Northwest India, the stagnation of wheat yields over the past decade presents a distressing contrast to the tremendous yield gains achieved during the Green Revolution. One commonly proposed way to raise yields is to reduce the often considerable gap between yield potential and average yields realized in farmers' fields, yet the likely effectiveness of different strategies to close this gap has been poorly known.
Feature-tracking techniques are employed to investigate why there is a relative minimum in storminess during winter within the Pacific storm track (the midwinter suppression). It is found that the frequency and amplitude of disturbances entering the Pacific storm track from midlatitude Asia are substantially reduced during winter relative to fall and spring and that the magnitude of this reduction is more than sufficient to account for the midwinter supression.
Accumulating evidence suggests that agricultural production could be greatly affected by climate change, but there remains little quantitative understanding of how these agricultural impacts would affect economic livelihoods in poor countries. Here we consider three scenarios of agricultural impacts of climate change by 2030 (impacts resulting in low, medium, or high productivity) and evaluate the resulting changes in global commodity prices, national economic welfare, and the incidence of poverty in a set of 15 developing countries.
There is widespread interest in the impacts of climate change on agriculture in Sub-Saharan Africa (SSA), and on the most effective investments to assist adaptation to these changes, yet the scientific basis for estimating production risks and prioritizing investments has been quite limited. Here we show that by combining historical crop production and weather data into a panel analysis, a robust model of yield response to climate change emerges for several key African crops.
Meeting the food needs of Africa's growing population over the next half-century will require technologies that significantly improve rural livelihoods at minimal environmental cost. These technologies will likely be distinct from those of the Green Revolution, which had relatively little impact in sub-Saharan Africa; consequently, few such interventions have been rigorously evaluated. This paper analyzes solar-powered drip irrigation as a strategy for enhancing food security in the rural Sudano-Sahel region of West Africa.
The ability to inventory and map soil salinity at regional scales remains a significant challenge to scientists concerned with the salinization of agricultural soils throughout the world. Previous attempts to use satellite or aerial imagery to assess soil salinity have found limited success in part because of the inability of methods to isolate the effects of soil salinity on vegetative growth from other factors.
In the 21st century, mapping and monitoring the occurrence of soil degradation will be an important component of successful land management. Remote sensing, with its unique ability to measure across space and time, will be an increasingly indispensible tool for assessing degradation. However, much of the recent experience and progress in using remote sensing and other geospatial technologies to map soil degradation is reported outside of the peer-reviewed literature.
The ongoing expansion of oil palm plantations in the humid tropics, especially in Southeast Asia, is generating considerable concern and debate. Amid industry and environmental campaigners' claims, it can be hard to perceive reality. Is oil palm a valuable route to sustainable development or a costly road to environmental ruin? Inevitably, any answer depends on many choices. But do decision makers have the information they require to avoid pitfalls and make the best decisions? This review examines what we know and what we don't know about oil palm developments.
In this chapter, we focus specifically on agricultural risks and uncertainties related to climate variability and global climate change from a policy viewpoint. Policymakers have little control over the weather, which is driven by very short-run (hourly to daily) patterns in atmosphere and ocean circulation. With good scientific information, however, policymakers in many regions can anticipate longer-run (monthly, yearly, decadal) climate variability and climate change reflected in patterns of
Higher growing season temperatures can have dramatic impacts on agricultural productivity, farm incomes, and food security. We used observational data and output from 23 global climate models to show a high probability (>90%) that growing season temperatures in the tropics and subtropics by the end of the 21st century will exceed the most extreme seasonal temperatures recorded from 1900 to 2006. In temperate regions, the hottest seasons on record will represent the future norm in many locations.
This paper presents data from six of the first countries incorporated into the Agricultural Lives of the Poor project: Ghana, Guatemala, India, Malawi, Uganda, and Vietnam. Datasets were selected based on availability and depth of detail on consumption expenditures, sources of income, and agricultural practices. Each of these survey components is necessary in order for ALP to focus on net consumption/production at the household level, and to understand expenditure and consumption behavior. Net consumption and production data of individual crops and
Armed conflict within nations has had disastrous humanitarian consequences throughout much of the world. Here we undertake the first comprehensive examination of whether global climate change will exacerbate armed conflict in sub-Saharan Africa. We find strong historical linkages between civil war and temperature on the continent, with warmer years leading to significant increases in the likelihood of war. When combined with climate model projections of future temperature trends, this historical response to temperature suggests a roughly 60% increase in armed conflict incidence by
Recent work has shown that current bio-energy policy directives may have harmful, indirect consequences, affecting both food security and the global climate system. An additional unintended but direct effect of large-scale biofuel production is the impact on local and regional climate resulting from changes in the energy and moisture balance of the surface upon conversion to biofuel crops.
In this article, I introduce the user-written command craggit, which simultaneously fits both tiers of Cragg’s (1971, Econometrica 39: 829–844) “twotier” (sometimes called “two-stage” or “double-hurdle”) alternative to tobit for corner-solution models. A key limitation to the tobit model is that the probability of a positive value and the actual value, given that it is positive, are determined by the same underlying process (i.e., the same parameters).
Aquaculture’s pressure on forage fisheries remains hotly contested. This article reviews trends in fishmeal and fish oil use in industrial aquafeeds, showing reduced inclusion rates but greater total use associated with increased aquaculture production and demand for fish high in long-chain omega-3 oils. The ratio of wild fisheries inputs to farmed fish output has fallen to 0.63 for the aquaculture sector as a whole but remains as high as 5.0 for Atlantic salmon.
This study uses regression analysis to evaluate the relationships among sea surface temperature anomalies (SSTA) averaged over the Niño-3.4 region (5°N-5°S, 120°-170°W), rainfall, and rice production, area harvested, and yield in Luzon, the large island on which most Philippine rice is grown. Previous research on Philippine rice production and El Niño-Southern Oscillation (ENSO) has found negative associations between El Niño events and rice yields in rainfed systems. This analysis goes further and shows that both irrigated and rainfed ecosystems are impacted.
This study investigates the skill of linear methods for downscaling provincial-scale precipitation over Indonesia from fields that describe the large-scale circulation and hydrological cycle. The study is motivated by the strong link between large-scale variations in the monsoon and the El Nino - Southern Oscillation (ENSO) phenomenon and regional precipitation, and the subsequent impact of regional precipitation on rice production in Indonesia.
Future trajectories of food prices, food security, and cropland expansion are closely linked to future average crop yields in the major agricultural regions of the world. Because the maximum possible yields achieved in farmers' fields might level off or even decline in many regions over the next few decades, reducing the gap between average and potential yields is critical. In most major irrigated wheat, rice, and maize systems, yields appear to be at or near 80% of yield potential, with no evidence for yields having exceeded this threshold to date. A
In June 2009, a group of experts in climate science, crop modeling, and crop development gathered at Stanford University to discuss the major needs for successful crop adaptation to climate change. To focus discussion over the three day period, the meeting centered on just three major crops – rice, wheat, and maize – given that these provide the bulk of calories to most populations. The meeting also focused on two aspects of climate– extreme high temperatures and extreme low moisture conditions (i.e.