Contributions of individual variation in temperature, solar radiation and precipitation to crop yield in the North China Plain, 1961–2003

An understanding of the relative impacts of the changes in climate variables on crop yield can help develop effective adaptation strategies to cope with climate change. This study was conducted to investigate the effects of the interannual variability and trends in temperature, solar radiation and precipitation during 1961–2003 on wheat and maize yields in a double cropping system at Beijing and Zhengzhou in the North China Plain (NCP), and to examine the relative contributions of each climate variable in isolation. 129 climate scenarios consisting of all the combinations of these climate variables were constructed. Each scenario contained 43 years of observed values of one variable, combined with values of the other two variables from each individual year repeated 43 times. The Agricultural Production Systems Simulator (APSIM) was used to simulate crop yields using the ensemble of generated climate scenarios. The results showed that the warming trend during the study period did not have significant impact on wheat yield potential at both sites, and only had significant negative impact on maize yield potential at Beijing. This is in contrast with previous results on effect of warming. The decreasing trend in solar radiation had a much greater impact on simulated yields of both wheat and maize crops, causing a significant reduction in potential yield of wheat and maize at Beijing. Although decreasing trends in rainfed yield of both simulated wheat and maize were found, the substantial interannual variability of precipitation made the trends less prominent

Wheat Yield Functions for Analysis of Land-Use Change in China

CERES-Wheat, a dynamic process crop growth model is specified and validated for eight sites in the major wheat-growing regions of China. Crop model results are then used to test functional forms for yield response to nitrogen fertilizer, irrigation water, temperature, and precipitation. The resulting functions are designed to be used in a linked biophysical-economic model of land-use and land-cover change. Variables explaining a significant proportion of simulated yield variance are nitrogen, irrigation water, and precipitation; temperature was not a significant component of yield variation within the range of observed year-to-year variability except at the warmest site. The Mitscherlich-Baule function is found to be more appropriate than the quadratic function at most sites. Crop model simulations with a generic soil with median characteristics of the eight sites were compared to simulations with site-specific soils, providing an initial test of the sensitivity of the functional forms to soil specification. The use of the generic soil does not affect the results significantly; thus, the functions may be considered representative of agriculturally productive regions with similar climate in China under intensifying management conditions

On the use and misuse of climate change projections in international development

Climate resilience is increasingly prioritized by international development agencies and national governments. However, current approaches to informing communities of future climate risk are problematic. The predominant focus on end-of-century projections neglects more pressing development concerns, which relate to the management of shorter-term risks and climate variability, and constitutes a substantial opportunity cost for the limited financial and human resources available to tackle development challenges. When a long-term view genuinely is relevant to decisionmaking, much of the information available is not fit for purpose. Climate model projections are able to capture many aspects of the climate system and so can be relied upon to guide mitigation plans and broad adaptation strategies, but the use of these models to guide local, practical adaptation actions is unwarranted. Climate models are unable to represent future conditions at the degree of spatial, temporal, and probabilistic precision with which projections are often provided, which gives a false impression of confidence to users of climate change information. In this article, we outline these issues, review their history, and provide a set of practical steps for both the development and climate scientist communities to consider. Solutions to mobilize the best available science include a focus on decision-relevant timescales, an increased role for model evaluation and expert judgment and the integration of climate variability into climate change service

Innovations in Climate Risk Management: Protecting and Building Rural Livelihoods in a Variable and Changing Climate

We argue that more effective management of climate risk must be part of the response of the international agriculture community to the double crisis of persistent poverty and a changing climate. The most promising opportunities to adapt to climate change involve action on shorter time scales that also contributes to immediate development challenges. Climate risk management (CRM) combines systematic use of climate information, and technology that reduces vulnerability and policy that transfers risk. The cost of climate risk comes both through damaging extreme events and through forfeited opportunity in climatically-favorable years. Effective CRM therefore involves managing the full range of variability, balancing hazard management with efforts to capitalize on opportunity. We discuss several innovations for managing climate risk in agriculture, which have not yet been fully mainstreamed in international agricultural research-for-development. First, effective rural climate information services enable farmers to adopt technology, intensify production, and invest in more profitable livelihoods when conditions are favorable; and to protect families and farms against the long-term consequences of adverse extremes. Second, information and decision support systems synthesize historic, monitored and forecast climate information into forms that are directly relevant to institutional decisions (planning, trade, food crisis response) that impact farmer livelihoods. Third, innovations in index-based insurance and credit overcome some of the limitations of traditional insurance, and are being applied to pre-financing food crisis response, and to removing credit constraints to adopting improved technology. We present a typology of CRM interventions around the concept of dynamic poverty traps

Better statistics to assess the quality of analogue-based forecast systems.

Seasonal probabilistic forecast systems (SPFS) based on the analogue years approach (AYA) are used worldwide and provide valuable information for decision makers managing climate-sensitive systems (Sivakumar et al. 2000; Ferreyra et al. 2001; Selvaraju et al. 2004; Meinke and Stone 2005). Providing such categorisations are based on scientifically well understood mechanisms, such forecasts (or, more appropriately, scenarios) allow climate time series to be partitioned into ?year- or season-types? (analogue years) based on prevailing ocean and atmospheric conditions (i.e. Southern Oscillation Index, SOI and/or Sea Surface Temperatures SST anomalies), resulting in SOI or ENSO phases. These time series are usually represented by their respective cumulative distribution functions (CDFs) or their complement, probability of exceeding functions (POEs): a conditional CDFK for each class K and an unconditional CDF (CDFALL). Current oceanic and atmospheric conditions can then be assigned to a particular category K and the correspondent CDFK is then adopted for probabilistic assessments. To take action, decisions makers need to know: a) whether or not probabilistic forecasts provided by conditional distributions are sufficiently different from their respective from `climatology?; b) if so, what is the magnitude of change in the prognostic variable that might lead to a change in the decision; c) is there sufficient improvement in accuracy over the ?climatology? and d) if so, what is the improvement in accuracy of this forecast over the unconditional case (Maia et al. 2006). From a methodological perspective, the assessment of questions (a) and (c) requires inferential tools such as statistical tests for the hypothesis of `no class effect´. The assessment of questions (b) and (d) requires intuitive, descriptive statistics that are relevant for the question at hand. We propose using descriptive measures coupled with inferential methods to evaluate such SPFS. Detailed discussion about forecast qualit yassessments can be found in Potgieter et al. 2004). We illustrate these approaches by quantifying signal of a SOI-based forecast system across Australia and an ENSO-based forecast system across Southeast of South America

Tropical Oceanic Causes of Interannual to Multidecadal Precipitation Variability in Southeast South America over the Past Century

Observations, atmosphere models forced by historical SSTs, and idealized simulations are used to determine the causes and mechanisms of interannual to multidecadal precipitation anomalies over southeast South America (SESA) since 1901. About 40% of SESA precipitation variability over this period can be accounted for by global SST forcing. Both the tropical Pacific and Atlantic Oceans share the driving of SESA precipitation, with the latter contributing the most on multidecadal time scales and explaining a wetting trend from the early midcentury until the end of the last century. Cold tropical Atlantic SST anomalies are shown to drive wet conditions in SESA. The dynamics that link SESA precipitation to tropical Atlantic SST anomalies are explored. Cold tropical Atlantic SST anomalies force equatorward-flowing upper-tropospheric flow to the southeast of the tropical heating anomaly, and the vorticity advection by this flow is balanced by vortex stretching and ascent, which drives the increased precipitation. The 1930s Pampas Dust Bowl drought occurred, via this mechanism, in response to warm tropical Atlantic SST anomalies. The atmospheric response to cold tropical Pacific SSTs also contributed. The tropical Atlantic SST anomalies linked to SESA precipitation are the tropical components of the Atlantic multidecadal oscillation. There is little evidence that the large trends over past decades are related to anthropogenic radiative forcing, although models project that this will cause a modest wetting of the climate of SESA. As such, and if the Atlantic multidecadal oscillation has shifted toward a warm phase, it should not be assumed that the long-term wetting trend in SESA will continue. Any reversal to a drier climate more typical of earlier decades would have clear consequences for regional agriculture and water resources

Climate risk management for water in semi-arid regions

Background: New sources of hydroclimate information based on forecast models and observational data have the potential to greatly improve the management of water resources in semi-arid regions prone to drought. Better management of climate-related risks and opportunities requires both new methods to develop forecasts of drought indicators and river flow, as well as better strategies to incorporate these forecasts into drought, river or reservoir management systems. In each case the existing institutional and policy context is key, making a collaborative approach involving stakeholders essential. Methods: This paper describes work done at the IRI over the past decade to develop statistical hydrologic forecast and water allocation models for the semi arid regions of NE Brazil (the “Nordeste”) and central northern Chile based on seasonal climate forecasts. Results: In both locations, downscaled precipitation forecasts based on lagged SST predictors or GCM precipitation forecasts exhibit quite high skill. Spring-summer melt flow in Chile is shown to be highly predictable based on estimates of previous winter precipitation, and moderately predictable up to 6 months in advance using climate forecasts. Retrospective streamflow forecasts here are quite effective in predicting reductions in water rights during dry years. For the multi-use Oros reservoir in NE Brazil, streamflow forecasts have the most potential to optimize water allocations during multi-year low-flow periods, while the potential is higher for smaller reservoirs, relative to demand. Conclusions: This work demonstrates the potential value of seasonal climate forecasting as an integral part of drought early warning and for water allocation decision support systems in semi-arid regions. As human demands for water rise over time this potential is certain to rise in the future

A farm-level evaluation of nitrogen and phosphorus fertilizer use and planting density for pearl millet production in Niger

Mineral fertilizer use is increasing in West Africa though little information is available on yield response in farmers' fields. Farmers in this region plant at low density (average 5,000 pockets ha−1, 3 plants pocket−1), which can affect fertilizer use efficiency. A study was conducted with 20 farmers in Niger to assess the response of pearl millet [Pennisetum glaucum (L.) R. Br.] to phosphorus and nitrogen fertilizers under farm conditions. In each field, treatments included control, single superphosphate (SSP) only, SSP plus N (point placed near plant), and either SSP or partially acidulated phosphate rock (PAPR) plus N broadcast. N and P were applied at 30 kg N ha−1 and 30 kg P2O5 ha−1. Farmers were allowed to plant, weed, etc., as they wished and they planted at densities ranging from 2,000 to 12,000 pockets ha−1. In the absence of fertilizer, increasing density from 2,000 to 7,000 pockets ha−1 increased yield by 400%. A strong interaction was found between fertilizer use and density. Farmers planting at densities less than 3,500 pockets ha−1 had average yields of 317 kg grain ha−1 while those planting at densities higher than 6,500 pockets ha−1 showed average yields of 977 grain ha−1. Though phosphate alone increased yields significantly at all densities, little response to fertilizer N was found at densities below 6,000 pockets ha−1. Significant residual responses in 1987 and 1988 were found to P applied in high-density plots in 1986. Depending on fertilizer and grain prices, analysis showed that fertilizer use must be be combined with high plant density (10,000 pockets ha−1) or no economic benefit from fertilizer use will be realize

The International Research Institute for Climate and Society: why, what and how

A climate-informed and climate-ready world is possible. Large investments are being made toward adaptation and resilience to climate change, but many of those investments are separated from the more immediate climate-related vulnerabilities and opportunities that society faces. Information is increasingly available that could be used to guide action; however, information alone is not sufficient. Research at the International Research Institute for Climate and Society (IRI) since 1996 has led to the identification of the several guiding principles to scope and address climate-related challenges to decision- and policy-makers at local-to-regional scale. These include climate-related information, such as assessment of the main vulnerabilities to climate variability and change in countries or regions, and the provision of climate information, products and tools to support decisions, including financial tools that are appropriate to the climate-related risk and that can mediate residual risk. The guiding principles also include identifying the technologies and practices that optimize results in coming years, demonstration of the usefulness of climate information to support climate-related decisions, training and capacity building, and partnerships for research and implementation. This essay introduces the evolution of the IRI and its work that is then elaborated through a series of articles that constitute a special issue of Earth Perspectives: Transdisciplinarity Enabled. The collection of articles provides insight into the science and process that lead to better climate-informed choices. Part of the collection of articles in the special issue covers specific stories of local-to-regional engagement with partners to address climate-related problems. Other articles represent how we do what we do, in particular highlighting the research, the climate forecast effort, and the IRI Data Library. Finally, there are two papers offered from partners that have long-time engagement with the IR