Integrating pests and pathogens into the climate change/food security debate
TL;DR: More mechanistic inclusion of pests and pathogen effects in crop models would lead to more realistic predictions of crop production on a regional scale and thereby assist in the development of more robust regional food security policies.
Abstract: While many studies have demonstrated the sensitivities of plants and of crop yield to a changing climate, a major challenge for the agricultural research community is to relate these findings to the broader societal concern with food security. This paper reviews the direct effects of climate on both crop growth and yield and on plant pests and pathogens and the interactions that may occur between crops, pests, and pathogens under changed climate. Finally, we consider the contribution that better understanding of the roles of pests and pathogens in crop production systems might make to enhanced food security. Evidence for the measured climate change on crops and their associated pests and pathogens is starting to be documented. Globally atmospheric [CO(2)] has increased, and in northern latitudes mean temperature at many locations has increased by about 1.0-1.4 degrees C with accompanying changes in pest and pathogen incidence and to farming practices. Many pests and pathogens exhibit considerable capacity for generating, recombining, and selecting fit combinations of variants in key pathogenicity, fitness, and aggressiveness traits that there is little doubt that any new opportunities resulting from climate change will be exploited by them. However, the interactions between crops and pests and pathogens are complex and poorly understood in the context of climate change. More mechanistic inclusion of pests and pathogen effects in crop models would lead to more realistic predictions of crop production on a regional scale and thereby assist in the development of more robust regional food security policies.
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TL;DR: It is argued that nascent fungal infections will cause increasing attrition of biodiversity, with wider implications for human and ecosystem health, unless steps are taken to tighten biosecurity worldwide.
Abstract: The past two decades have seen an increasing number of virulent infectious diseases in natural populations and managed landscapes. In both animals and plants, an unprecedented number of fungal and fungal-like diseases have recently caused some of the most severe die-offs and extinctions ever witnessed in wild species, and are jeopardizing food security. Human activity is intensifying fungal disease dispersal by modifying natural environments and thus creating new opportunities for evolution. We argue that nascent fungal infections will cause increasing attrition of biodiversity, with wider implications for human and ecosystem health, unless steps are taken to tighten biosecurity worldwide.
2,408 citations
TL;DR: In this paper, a comprehensive summary of studies that simulate climate change impacts on agriculture are reported in a meta-analysis, which suggests that aggregate yield losses should be expected for wheat, rice and maize in temperate and tropical growing regions even under relatively moderate levels of local warming.
Abstract: A comprehensive summary of studies that simulate climate change impacts on agriculture are now reported in a meta-analysis. Findings suggest that, without measures to adapt to changing conditions, aggregate yield losses should be expected for wheat, rice and maize in temperate and tropical growing regions even under relatively moderate levels of local warming.
1,458 citations
TL;DR: This work proposes a framework based on ideas from global-change biology, community ecology, and invasion biology that uses community modules to assess how species interactions shape responses to climate change.
Abstract: Predicting the impacts of climate change on species is one of the biggest challenges that ecologists face Predictions routinely focus on the direct effects of climate change on individual species, yet interactions between species can strongly influence how climate change affects organisms at every scale by altering their individual fitness, geographic ranges and the structure and dynamics of their community Failure to incorporate these interactions limits the ability to predict responses of species to climate change We propose a framework based on ideas from global-change biology, community ecology, and invasion biology that uses community modules to assess how species interactions shape responses to climate change
1,169 citations
01 Jan 2014
TL;DR: The questions for this chapter are how far climate and its change affect current food production systems and food security and the extent to which they will do so in the future.
Abstract: Many definitions of food security exist, and these have been the subject of much debate. As early as 1992, Maxwell and Smith (1992) reviewed more than 180 items discussing concepts and definitions, and more definitions have been formulated since (DEFRA, 2006). Whereas many earlier definitions centered on food production, more recent definitions highlight access to food, in keeping with the 1996 World Food Summit definition (FAO, 1996) that food security is met when “all people, at all times, have physical and economic access to sufficient, safe, and nutritious food to meet their dietary needs and food preferences for an active and healthy life.” Worldwide attention on food access was given impetus by the food “price spike” in 2007–2008, triggered by a complex set of long- and short-term factors (FAO, 2009b; von Braun and Torero, 2009). FAO concluded, “provisional estimates show that, in 2007, 75 million more people were added to the total number of undernourished relative to 2003–05” (FAO, 2008); this is arguably a low-end estimate (Headey and Fan, 2010). More than enough food is currently produced per capita to feed the global population, yet about 870 million people remained hungry in the period from 2010 to 2012 (FAO et al., 2012). The questions for this chapter are how far climate and its change affect current food production systems and food security and the extent to which they will do so in the future (Figure 7-1).
960 citations
Cites background from "Integrating pests and pathogens int..."
...The potential influence of pests and diseases is commonly beyond the scope of such studies (Gregory et al., 2009)....
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TL;DR: This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty.
Abstract: This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty. Few global-scale assessments have been carried out, and these are limited in their ability to capture the uncertainty in climate projections, and omit potentially important aspects such as extreme events and changes in pests and diseases. There is a lack of clarity on how climate change impacts on drought are best quantified from an agricultural perspective, with different metrics giving very different impressions of future risk. The dependence of some regional agriculture on remote rainfall, snowmelt and glaciers adds to the complexity. Indirect impacts via sea-level rise, storms and diseases have not been quantified. Perhaps most seriously, there is high uncertainty in the extent to which the direct effects of CO2 rise on plant physiology will interact with climate change in affecting productivity. At present, the aggregate impacts of climate change on global-scale agricultural productivity cannot be reliably quantified.
828 citations
Cites background from "Integrating pests and pathogens int..."
...This may be through impacts of warming or drought on the resistance of crops to specific diseases and through the increased pathogenicity of organisms by mutation induced by environmental stress (Gregory et al. 2009)....
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References
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TL;DR: Free-air concentration enrichment (FACE) technology has now facilitated large-scale trials of the major grain crops at elevated [CO2] under fully open-air field conditions, which casts serious doubt on projections that rising carbon dioxide concentration will fully offset losses due to climate change.
Abstract: Model projections suggest that although increased temperature and decreased soil moisture will act to reduce global crop yields by 2050, the direct fertilization effect of rising carbon dioxide concentration ([CO 2 ]) will offset these losses. The CO 2 fertilization factors used in models to project future yields were derived from enclosure studies conducted approximately 20 years ago. Free-air concentration enrichment (FACE) technology has now facilitated large-scale trials of the major grain crops at elevated [CO2] under fully open-air field conditions. In those trials, elevated [CO2] enhanced yield by E50% less than in enclosure studies. This casts serious doubt on projections that rising [CO2] will fully offset losses due to climate change.
1,453 citations
"Integrating pests and pathogens int..." refers background in this paper
...Estimates of the CO2 fertilization effect vary depending on which experimental approach is used (Long et al., 2006; Tubiello et al., 2007a; Ziska and Bunce, 2007; Ainsworth et al., 2008), but current estimates for increases in crop yield are 10–20% for C3 crops and 0–10% for C4 crops (Ainsworth and…...
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...Ingram et al. (2008) outlined three major challenges for agronomic research in the climate/food security debate: (i) to understand better how climate change will affect cropping systems (as opposed to crop productivity); (ii) to assess technical and policy options for reducing the deleterious…...
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TL;DR: In this article, the authors present a range of climate change scenarios for Africa, focusing on changes in both continental and regional seasonal-mean temperature and rainfall, and estimate the associated changes in global CO2 concentration and global mean sea-level change.
Abstract: This paper reviews observed (1900-2000) and possible future (2000-2100) continent- wide changes in temperature and rainfall for Africa. For the historic period we draw upon a new observed global climate data set which allows us to explore aspects of regional climate change related to diurnal temperature range and rainfall variability. The latter includes an investigation of regions where seasonal rainfall is sensitive to El Nino climate variability. This review of past climate change provides the context for our scenarios of future greenhouse gas-induced climate change in Africa. These scenarios draw upon the draft emissions scenarios prepared for the Intergovernmental Panel on Climate Change's Third Assessment Report, a suite of recent global climate model experi- ments, and a simple climate model to link these 2 sets of analyses. We present a range of 4 climate futures for Africa, focusing on changes in both continental and regional seasonal-mean temperature and rainfall. Estimates of associated changes in global CO2 concentration and global-mean sea-level change are also supplied. These scenarios draw upon some of the most recent climate modelling work. We also identify some fundamental limitations to knowledge with regard to future African cli- mate. These include the often poor representation of El Nino climate variability in global climate models, and the absence in these models of any representation of regional changes in land cover and dust and biomass aerosol loadings. These omitted processes may well have important consequences for future African climates, especially at regional scales. We conclude by discussing the value of the sort of climate change scenarios presented here and how best they should be used in national and regional vulnerability and adaptation assessments.
1,330 citations
"Integrating pests and pathogens int..." refers background in this paper
...The last 40–50 years have seen major changes to agricultural systems worldwide that have contributed to, and interacted with, new food systems. Von Braun (2007) highlighted the transforming role of the interacting driving forces of population increase, income growth, urbanization, and globalization on food production, markets, and consumption....
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...Few studies addressing the impacts of climate change on crop yield have incorporated the effects of crop pests. For example, when reviewing how elevated [CO2] might affect crop yields, Ziska and Bunce (2007) listed only two papers that considered how insect pests might modify the predictions....
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...Hulme et al. (2001) suggest that precipitation patterns in Southern Africa are likely to decrease in December–February, but increase in June–August when this will most benefit S....
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...Hulme et al. (2001) suggest that precipitation patterns in Southern Africa are likely to decrease in December–February, but increase in June–August when this will most benefit S. gregaria and lead to further problems....
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TL;DR: It is shown that dispersal and interactions, which are important elements of population dynamics, must be included in predictions of biotic responses to climate change.
Abstract: Many attempts to predict the biotic responses to climate change rely on the 'climate envelope' approach, in which the current distribution of a species is mapped in climate-space and then, if the position of that climate-space changes, the distribution of the species is predicted to shift accordingly. The flaw in this approach is that distributions of species also reflect the influence of interactions with other species, so predictions based on climate envelopes may be very misleading if the interactions between species are altered by climate change. An additional problem is that current distributions may be the result of sources and sinks, in which species appear to thrive in places where they really persist only because individuals disperse into them from elsewhere. Here we use microcosm experiments on simple but realistic assemblages to show how misleading the climate envelope approach can be. We show that dispersal and interactions, which are important elements of population dynamics, must be included in predictions of biotic responses to climate change.
1,161 citations
"Integrating pests and pathogens int..." refers background in this paper
...While such approaches are open to criticism because climate alone does not determine distribution and species interactions are ignored (Davis et al., 1998), climatic mapping provides a pragmatic means of investigating the potential for exotic pests and pathogens to establish in new areas (Baker et…...
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...species interactions are ignored (Davis et al., 1998), climatic mapping provides a pragmatic means of investigating the potential for exotic pests and pathogens to establish in new areas (Baker et al....
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TL;DR: In this paper, a framework for studying the multiple interactions of broadly defined food systems with global environmental change and evaluating the major societal outcomes affected by these interactions: food security, ecosystem services and social welfare is presented.
Abstract: This paper outlines a framework for studying the multiple interactions of broadly defined food systems with global environmental change and evaluating the major societal outcomes affected by these interactions: food security, ecosystem services and social welfare. In building the framework the paper explores and synthesizes disparate literature on food systems food security and global environmental change, bridging social science and natural science perspectives. This collected evidence justifies a representation of food systems, which can be used to identify key processes and determinants of food security in a given place or time, particularly the impacts of environmental change. It also enables analysis of the feedbacks from food system outcomes to drivers of environmental and social change, as well as tradeoffs among the food system outcomes themselves. In food systems these tradeoffs are often between different scales or levels of decision-making or management, so solutions to manage them must be context-specific. With sufficient empirical evidence, the framework could be used to build a database of typologies of food system interactions useful for different management or analytical purposes.
1,048 citations
"Integrating pests and pathogens int..." refers background in this paper
...…only with food availability (production, distribution, and exchange) but also with access to, and utilization of, food so that studies which focus only on agricultural production only provide a partial assessment of food security/climate change relationships (Gregory et al., 2005; Ericksen, 2008)....
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...It is well known that the sensitivity of agricultural systems to climate differs between systems depending on whether they are temperature- or water-limited, and whether they are operating near their optimum or not....
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TL;DR: Improved systems of food production, food distribution and economic access may all contribute to food systems adapted to cope with climate change, but in adopting such changes it will be important to ensure that they contribute to sustainability.
Abstract: Dynamic interactions between and within the biogeophysical and human environments lead to the production, processing, distribution, preparation and consumption of food, resulting in food systems that underpin food security. Food systems encompass food availability (production, distribution and exchange), food access (affordability, allocation and preference) and food utilization (nutritional and societal values and safety), so that food security is, therefore, diminished when food systems are stressed. Such stresses may be induced by a range of factors in addition to climate change and/or other agents of environmental change (e.g. conflict, HIV/AIDS) and may be particularly severe when these factors act in combination. Urbanization and globalization are causing rapid changes to food systems.
Climate change may affect food systems in several ways ranging from direct effects on crop production (e.g. changes in rainfall leading to drought or flooding, or warmer or cooler temperatures leading to changes in the length of growing season), to changes in markets, food prices and supply chain infrastructure. The relative importance of climate change for food security differs between regions. For example, in southern Africa, climate is among the most frequently cited drivers of food insecurity because it acts both as an underlying, ongoing issue and as a short-lived shock. The low ability to cope with shocks and to mitigate long-term stresses means that coping strategies that might be available in other regions are unavailable or inappropriate. In other regions, though, such as parts of the Indo-Gangetic Plain of India, other drivers, such as labour issues and the availability and quality of ground water for irrigation, rank higher than the direct effects of climate change as factors influencing food security.
Because of the multiple socio-economic and bio-physical factors affecting food systems and hence food security, the capacity to adapt food systems to reduce their vulnerability to climate change is not uniform. Improved systems of food production, food distribution and economic access may all contribute to food systems adapted to cope with climate change, but in adopting such changes it will be important to ensure that they contribute to sustainability. Agriculture is a major contributor of the greenhouse gases methane (CH4) and nitrous oxide (N2O), so that regionally derived policies promoting adapted food systems need to mitigate further climate change.
1,022 citations
"Integrating pests and pathogens int..." refers background in this paper
...Food security (defined as when all people, at all times, have physical and economic access to sufficient, safe, and nutritious food to meet their dietary needs and food preferences for an active and healthy life, FAO) is concerned not only with food availability (production, distribution, and exchange) but also with access to, and utilization of, food so that studies which focus only on agricultural production only provide a partial assessment of food security/climate change relationships (Gregory et al., 2005; Ericksen, 2008)....
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...…only with food availability (production, distribution, and exchange) but also with access to, and utilization of, food so that studies which focus only on agricultural production only provide a partial assessment of food security/climate change relationships (Gregory et al., 2005; Ericksen, 2008)....
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...Gregory et al. (2005) demonstrated that climate variation is only one of several interacting factors that affect food security....
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