Many studies have estimated the adverse effects of climate change on crop yields, however, this l... more Many studies have estimated the adverse effects of climate change on crop yields, however, this literature almost universally assumes a constant geographic distribution of crops in the future. Movement of growing areas to limit exposure to adverse climate conditions has been discussed as a theoretical adaptive response but has not previously been quantified or demonstrated at a global scale. Here, we assess how changes in rainfed crop area have already mediated growing season temperature trends for rainfed maize, wheat, rice, and soybean using spatially-explicit climate and crop area data from 1973 to 2012. Our results suggest that the most damaging impacts of warming on rainfed maize, wheat, and rice have been substantially moderated by the migration of these crops over time and the expansion of irrigation. However, continued migration may incur substantial environmental costs and will depend on socio-economic and political factors in addition to land suitability and climate.
In this issue of One Earth, zu Ermgassen et al. provide recommendations for transforming policies... more In this issue of One Earth, zu Ermgassen et al. provide recommendations for transforming policies such as ''no net loss'' to effectively mitigate the full range of impacts from infrastructure development. But will avoiding harm be enough? A redesign of policies might be needed for achieving the full suite of Sustainable Development Goals.
Crop yields are projected to decrease under future climate conditions, and recent research sugges... more Crop yields are projected to decrease under future climate conditions, and recent research suggests that yields have already been impacted. However, current impacts on a diversity of crops subnationally and implications for food security remains unclear. Here, we constructed linear regression relationships using weather and reported crop data to assess the potential impact of observed climate change on the yields of the top ten global crops-barley, cassava, maize, oil palm, rapeseed, rice, sorghum, soybean, sugarcane and wheat at 20,000 political units. We find that the impact of global climate change on yields of different crops from climate trends ranged from-13.4% (oil palm) to 3.5% (soybean). Our results show that impacts are mostly negative in Europe, Southern Africa and Australia but generally positive in Latin America. Impacts in Asia and Northern and Central America are mixed. This has likely led to~1% average reduction (-3.5 X 10 13 kcal/year) in consumable food calories in these ten crops. In nearly half of food insecure countries, estimated caloric availability decreased. Our results suggest that climate change has already affected global food production.
Mapping suitable land for development is essential to land use planning efforts that aim to model... more Mapping suitable land for development is essential to land use planning efforts that aim to model, anticipate, and manage trade-offs between economic development and the environment. Previous land suitability assessments have generally focused on a few development sectors or lack consistent methodologies, thereby limiting our ability to plan for cumulative development pressures across geographic regions. Here, we generated 1-km spatially-explicit global land suitability maps, referred to as "development potential indices" (DPIs), for 13 sectors related to renewable energy (concentrated solar power, photovoltaic solar, wind, hydropower), fossil fuels (coal, conventional and unconventional oil and gas), mining (metallic, non-metallic), and agriculture (crop, biofuels expansion). To do so, we applied spatial multi-criteria decision analysis techniques that accounted for both resource potential and development feasibility. For each DPI, we examined both uncertainty and sensitivity, and spatially validated the map using locations of planned development. We illustrate how these DPIs can be used to elucidate potential individual sector expansion and cumulative development patterns.
Climate-smart agriculture (CSA) is widely promoted as an approach for reorienting agricultural de... more Climate-smart agriculture (CSA) is widely promoted as an approach for reorienting agricultural development under the realities of climate change. Prioritising research-for-development activities is crucial, given the need to utilise scarce resources as effectively as possible. However, no framework exists for assessing and comparing different CSA research investments. Several aspects make it challenging to prioritise CSA research, including its multi-dimensional nature (productivity, adaptation and mitigation), the uncertainty surrounding many climate impacts, and the scale and temporal dependencies that may affect the benefits and costs of CSA adoption. Here we propose a framework for prioritising agricultural research investments across scales and review different approaches to setting priorities among agricultural research projects. Many priority-setting case studies address the short-to medium-term and at relatively local scales. We suggest that a mix of actions that span spatial and temporal time scales is needed to be adaptive to a changing climate, address immediate problems and create enabling conditions for enduring change.
The Brazilian Soy Moratorium has effectively reduced forest conversion for soybeans in 47 Amazoni... more The Brazilian Soy Moratorium has effectively reduced forest conversion for soybeans in 47 Amazonia. This has come at the expense of the region's pasturelands, which have increasingly 48 ceded space for compliant soy expansion. The question of extending the policy to the Cerrado, 49 where recent soy expansion has come at the cost of ecologically valuable vegetation, plugs into a wider discussion on how to reconcile competing commodities on finite amounts of cleared area. 51 Innovative management strategies that allow different land uses to coexist are urgently needed. 52 Integrated crop-livestock systems with soybeans (ICLS) rotates beef and soy on the same area, and 53 shows promise as a means to improve production, farmer benefit, and environmental impacts. Here 54 we reconstruct historical land use maps to estimate Cerrado Soy Moratorium outcomes with 55 benchmark years in 2008 and 2014, we then estimate additional production afforded by ICLS 56 implementation between 2008 and 2014. We find that if a 2008 Cerrado Soy Moratorium were in 57 place, 0.7 Mha of 2014 Cerrado soy area would currently be in violation of the policy. Roughly 58 96% of this acreage is found in Matopiba (82%) and Mato Grosso (14%) states, suggesting that 59 adoption may have slowed recent production in these rapidly transforming soy centers, in contrast 60 to central and southwestern Cerrado where there is more concentrated eligible expansion area. 61 Changing the benchmark to 2014 could have added 0.7 Mha of eligible expansion area, though 62 over 80% of these additions would be in states with the most 2008 eligible area (Distrito Federal, 63 Mato Grosso, Maranhão, Minas Gerais, Mato Grosso do Sul). Meanwhile, ICLS adoption could 64 have added between 4.0 Mha and 32 Mha of new soy land to the study area without additional 65 clearing between 2008 and 2014, though this would depend on rigorous accompanying land zoning 66 policy to guide implementation. The roughly 5 Mha of Cerrado soybean expansion that actually 67 occurred between 2008 and 2014 could have been accommodated on 2008 suitable pasture area 68 given an ICLS rotation frequency of every 6 years or less. Conservation estimates presented here 69 represent the upper limit of what is possible, as our scenario modeling does not account for 70 variables such as leakage, laundering, or rebound effects.
Global agriculture is under pressure to meet increasing demand for food and agricultural products... more Global agriculture is under pressure to meet increasing demand for food and agricultural products. There are several global assessments of crop yields, but we know little about the uncertainties of their key findings, as the assessments are driven by the single best yield dataset available when each assessment was conducted. Recently, two different spatially explicit, global, historical yield datasets, one based on agricultural census and the other largely based on satellite remote sensing, became available. Using these datasets, we compare the similarities and differences in global yield gaps, trend patterns, growth rates and changes in year-to-year variability. We analyzed maize, rice, wheat and soybean for the period of 1981 to 2008 at four resolutions (0.083°, 0.5°, 1.0° and 2.0°). Although estimates varied by dataset and resolution, the global mean annual growth rates of 1.7-1.8%, 1.5-1.7%, 1.1-1.3% and 1.4-1.6% for maize, rice, wheat and soybean, respectively, are not on track...
Information about the global structure of agriculture and nutrient production and its diversity i... more Information about the global structure of agriculture and nutrient production and its diversity is essential to improve present understanding of national food production patterns, agricultural livelihoods, and food chains, and their linkages to land use and their associated ecosystems services. Here we provide a plausible breakdown of global agricultural and nutrient production by farm size, and also study the associations between farm size, agricultural diversity, and nutrient production. This analysis is crucial to design interventions that might be appropriately targeted to promote healthy diets and ecosystems in the face of population growth, urbanisation, and climate change. We used existing spatially-explicit global datasets to estimate the production levels of 41 major crops, seven livestock, and 14 aquaculture and fish products. From overall production estimates, we estimated the production of vitamin A, vitamin B12, folate, iron, zinc, calcium, calories, and protein. We als...
More than 100 countries pledged to reduce agricultural greenhouse gas (GHG) emissions (Richards e... more More than 100 countries pledged to reduce agricultural greenhouse gas (GHG) emissions (Richards et al., 2015a) in the 2015 Paris Agreement of the United Nations Framework Convention on Climate Change. Yet technical information about how much mitigation is needed in the sector versus how much is feasible remains poor. We identify a preliminary global target for reducing emissions from agriculture of ~1 GtCO2 e/yr by 2030 to limit warming in 2100 to 2°C above pre-industrial levels. Yet plausible agricultural development pathways with mitigation co-benefits deliver only 21 to 40% of needed mitigation. The target indicates that more transformative technical and policy options will be needed, such as methane inhibitors and finance for new practices. A more comprehensive target for the 2°C limit should be developed to include soil carbon and agriculture-related mitigation options. Excluding agricultural emissions from mitigation targets and plans will increase the cost of mitigation in ot...
Abstract Use of synthetic nitrogen fertilizer has greatly contributed to the increased crop yield... more Abstract Use of synthetic nitrogen fertilizer has greatly contributed to the increased crop yields brought about by the Green Revolution. Unfortunately, it also has also contributed to substantial excess nitrogen in the environment. Application of excess nitrogen not only is a waste of energy and other resources used to produce, transport and apply it, it also pollutes aquatic ecosystems and has led to the development of more than 200 hypoxic-or" dead"-zones in coastal areas around the world. How can we decrease use of excess nitrogen ...
With increasing nitrogen (N) application to croplands required to support growing food demand, mi... more With increasing nitrogen (N) application to croplands required to support growing food demand, mitigating N 2 O emissions from agricultural soils is a global challenge. National greenhouse gas emissions accounting typically estimates N 2 O emissions at the country scale by aggregating all crops, under the assumption that N 2 O emissions are linearly related to N application. However, field studies and meta-analyses indicate a nonlinear relationship, in which N 2 O emissions are relatively greater at higher N application rates. Here we apply a super-linear emissions response model to crop-specific, spatially-explicit synthetic N fertilizer and manure N inputs to provide subnational accounting of global N 2 O emissions from croplands. We estimate 0.66 Tg of N 2 ON direct global emissions circa 2000, with 50% of emissions concentrated in 13% of harvested area. Compared to estimates from the IPCC Tier 1 linear model, our updated N 2 O emissions range from 20-40% lower throughout Sub-Saharan Africa and Eastern Europe, to >120% greater in some Western European countries. At low N application rates, the weak non-linear response of N 2 O emissions suggests that relatively large increases in N fertilizer application would generate relatively small increases in N 2 O emissions. Since aggregated fertilizer data generate Accepted Article This article is protected by copyright. All rights reserved. underestimation bias in nonlinear models, high-resolution N application data are critical to support accurate N 2 O emissions estimates.
Half of the seafood consumed globally now comes from aquaculture, or farmed seafood. Aquaculture ... more Half of the seafood consumed globally now comes from aquaculture, or farmed seafood. Aquaculture therefore plays an increasingly important role in the global food system, the environment, and human health. Traditionally, aquaculture feed has contained high levels of wild fish, which is unsustainable for ocean ecosystems as demand grows. The aquaculture industry is shifting to crop-based feed ingredients, such as soy, to replace wild fish as a feed source and allow for continued industry growth. This shift fundamentally links seafood production to terrestrial agriculture, and multidisciplinary research is needed to understand the ecological and environmental health implications. We provide basic estimates of the agricultural resource use associated with producing the top five crops used in commercial aquaculture feed. Aquaculture's environmental footprint may now include nutrient and pesticide runoff from industrial crop production, and depending on where and how feed crops are p...
Many studies have estimated the adverse effects of climate change on crop yields, however, this l... more Many studies have estimated the adverse effects of climate change on crop yields, however, this literature almost universally assumes a constant geographic distribution of crops in the future. Movement of growing areas to limit exposure to adverse climate conditions has been discussed as a theoretical adaptive response but has not previously been quantified or demonstrated at a global scale. Here, we assess how changes in rainfed crop area have already mediated growing season temperature trends for rainfed maize, wheat, rice, and soybean using spatially-explicit climate and crop area data from 1973 to 2012. Our results suggest that the most damaging impacts of warming on rainfed maize, wheat, and rice have been substantially moderated by the migration of these crops over time and the expansion of irrigation. However, continued migration may incur substantial environmental costs and will depend on socio-economic and political factors in addition to land suitability and climate.
In this issue of One Earth, zu Ermgassen et al. provide recommendations for transforming policies... more In this issue of One Earth, zu Ermgassen et al. provide recommendations for transforming policies such as ''no net loss'' to effectively mitigate the full range of impacts from infrastructure development. But will avoiding harm be enough? A redesign of policies might be needed for achieving the full suite of Sustainable Development Goals.
Crop yields are projected to decrease under future climate conditions, and recent research sugges... more Crop yields are projected to decrease under future climate conditions, and recent research suggests that yields have already been impacted. However, current impacts on a diversity of crops subnationally and implications for food security remains unclear. Here, we constructed linear regression relationships using weather and reported crop data to assess the potential impact of observed climate change on the yields of the top ten global crops-barley, cassava, maize, oil palm, rapeseed, rice, sorghum, soybean, sugarcane and wheat at 20,000 political units. We find that the impact of global climate change on yields of different crops from climate trends ranged from-13.4% (oil palm) to 3.5% (soybean). Our results show that impacts are mostly negative in Europe, Southern Africa and Australia but generally positive in Latin America. Impacts in Asia and Northern and Central America are mixed. This has likely led to~1% average reduction (-3.5 X 10 13 kcal/year) in consumable food calories in these ten crops. In nearly half of food insecure countries, estimated caloric availability decreased. Our results suggest that climate change has already affected global food production.
Mapping suitable land for development is essential to land use planning efforts that aim to model... more Mapping suitable land for development is essential to land use planning efforts that aim to model, anticipate, and manage trade-offs between economic development and the environment. Previous land suitability assessments have generally focused on a few development sectors or lack consistent methodologies, thereby limiting our ability to plan for cumulative development pressures across geographic regions. Here, we generated 1-km spatially-explicit global land suitability maps, referred to as "development potential indices" (DPIs), for 13 sectors related to renewable energy (concentrated solar power, photovoltaic solar, wind, hydropower), fossil fuels (coal, conventional and unconventional oil and gas), mining (metallic, non-metallic), and agriculture (crop, biofuels expansion). To do so, we applied spatial multi-criteria decision analysis techniques that accounted for both resource potential and development feasibility. For each DPI, we examined both uncertainty and sensitivity, and spatially validated the map using locations of planned development. We illustrate how these DPIs can be used to elucidate potential individual sector expansion and cumulative development patterns.
Climate-smart agriculture (CSA) is widely promoted as an approach for reorienting agricultural de... more Climate-smart agriculture (CSA) is widely promoted as an approach for reorienting agricultural development under the realities of climate change. Prioritising research-for-development activities is crucial, given the need to utilise scarce resources as effectively as possible. However, no framework exists for assessing and comparing different CSA research investments. Several aspects make it challenging to prioritise CSA research, including its multi-dimensional nature (productivity, adaptation and mitigation), the uncertainty surrounding many climate impacts, and the scale and temporal dependencies that may affect the benefits and costs of CSA adoption. Here we propose a framework for prioritising agricultural research investments across scales and review different approaches to setting priorities among agricultural research projects. Many priority-setting case studies address the short-to medium-term and at relatively local scales. We suggest that a mix of actions that span spatial and temporal time scales is needed to be adaptive to a changing climate, address immediate problems and create enabling conditions for enduring change.
The Brazilian Soy Moratorium has effectively reduced forest conversion for soybeans in 47 Amazoni... more The Brazilian Soy Moratorium has effectively reduced forest conversion for soybeans in 47 Amazonia. This has come at the expense of the region's pasturelands, which have increasingly 48 ceded space for compliant soy expansion. The question of extending the policy to the Cerrado, 49 where recent soy expansion has come at the cost of ecologically valuable vegetation, plugs into a wider discussion on how to reconcile competing commodities on finite amounts of cleared area. 51 Innovative management strategies that allow different land uses to coexist are urgently needed. 52 Integrated crop-livestock systems with soybeans (ICLS) rotates beef and soy on the same area, and 53 shows promise as a means to improve production, farmer benefit, and environmental impacts. Here 54 we reconstruct historical land use maps to estimate Cerrado Soy Moratorium outcomes with 55 benchmark years in 2008 and 2014, we then estimate additional production afforded by ICLS 56 implementation between 2008 and 2014. We find that if a 2008 Cerrado Soy Moratorium were in 57 place, 0.7 Mha of 2014 Cerrado soy area would currently be in violation of the policy. Roughly 58 96% of this acreage is found in Matopiba (82%) and Mato Grosso (14%) states, suggesting that 59 adoption may have slowed recent production in these rapidly transforming soy centers, in contrast 60 to central and southwestern Cerrado where there is more concentrated eligible expansion area. 61 Changing the benchmark to 2014 could have added 0.7 Mha of eligible expansion area, though 62 over 80% of these additions would be in states with the most 2008 eligible area (Distrito Federal, 63 Mato Grosso, Maranhão, Minas Gerais, Mato Grosso do Sul). Meanwhile, ICLS adoption could 64 have added between 4.0 Mha and 32 Mha of new soy land to the study area without additional 65 clearing between 2008 and 2014, though this would depend on rigorous accompanying land zoning 66 policy to guide implementation. The roughly 5 Mha of Cerrado soybean expansion that actually 67 occurred between 2008 and 2014 could have been accommodated on 2008 suitable pasture area 68 given an ICLS rotation frequency of every 6 years or less. Conservation estimates presented here 69 represent the upper limit of what is possible, as our scenario modeling does not account for 70 variables such as leakage, laundering, or rebound effects.
Global agriculture is under pressure to meet increasing demand for food and agricultural products... more Global agriculture is under pressure to meet increasing demand for food and agricultural products. There are several global assessments of crop yields, but we know little about the uncertainties of their key findings, as the assessments are driven by the single best yield dataset available when each assessment was conducted. Recently, two different spatially explicit, global, historical yield datasets, one based on agricultural census and the other largely based on satellite remote sensing, became available. Using these datasets, we compare the similarities and differences in global yield gaps, trend patterns, growth rates and changes in year-to-year variability. We analyzed maize, rice, wheat and soybean for the period of 1981 to 2008 at four resolutions (0.083°, 0.5°, 1.0° and 2.0°). Although estimates varied by dataset and resolution, the global mean annual growth rates of 1.7-1.8%, 1.5-1.7%, 1.1-1.3% and 1.4-1.6% for maize, rice, wheat and soybean, respectively, are not on track...
Information about the global structure of agriculture and nutrient production and its diversity i... more Information about the global structure of agriculture and nutrient production and its diversity is essential to improve present understanding of national food production patterns, agricultural livelihoods, and food chains, and their linkages to land use and their associated ecosystems services. Here we provide a plausible breakdown of global agricultural and nutrient production by farm size, and also study the associations between farm size, agricultural diversity, and nutrient production. This analysis is crucial to design interventions that might be appropriately targeted to promote healthy diets and ecosystems in the face of population growth, urbanisation, and climate change. We used existing spatially-explicit global datasets to estimate the production levels of 41 major crops, seven livestock, and 14 aquaculture and fish products. From overall production estimates, we estimated the production of vitamin A, vitamin B12, folate, iron, zinc, calcium, calories, and protein. We als...
More than 100 countries pledged to reduce agricultural greenhouse gas (GHG) emissions (Richards e... more More than 100 countries pledged to reduce agricultural greenhouse gas (GHG) emissions (Richards et al., 2015a) in the 2015 Paris Agreement of the United Nations Framework Convention on Climate Change. Yet technical information about how much mitigation is needed in the sector versus how much is feasible remains poor. We identify a preliminary global target for reducing emissions from agriculture of ~1 GtCO2 e/yr by 2030 to limit warming in 2100 to 2°C above pre-industrial levels. Yet plausible agricultural development pathways with mitigation co-benefits deliver only 21 to 40% of needed mitigation. The target indicates that more transformative technical and policy options will be needed, such as methane inhibitors and finance for new practices. A more comprehensive target for the 2°C limit should be developed to include soil carbon and agriculture-related mitigation options. Excluding agricultural emissions from mitigation targets and plans will increase the cost of mitigation in ot...
Abstract Use of synthetic nitrogen fertilizer has greatly contributed to the increased crop yield... more Abstract Use of synthetic nitrogen fertilizer has greatly contributed to the increased crop yields brought about by the Green Revolution. Unfortunately, it also has also contributed to substantial excess nitrogen in the environment. Application of excess nitrogen not only is a waste of energy and other resources used to produce, transport and apply it, it also pollutes aquatic ecosystems and has led to the development of more than 200 hypoxic-or" dead"-zones in coastal areas around the world. How can we decrease use of excess nitrogen ...
With increasing nitrogen (N) application to croplands required to support growing food demand, mi... more With increasing nitrogen (N) application to croplands required to support growing food demand, mitigating N 2 O emissions from agricultural soils is a global challenge. National greenhouse gas emissions accounting typically estimates N 2 O emissions at the country scale by aggregating all crops, under the assumption that N 2 O emissions are linearly related to N application. However, field studies and meta-analyses indicate a nonlinear relationship, in which N 2 O emissions are relatively greater at higher N application rates. Here we apply a super-linear emissions response model to crop-specific, spatially-explicit synthetic N fertilizer and manure N inputs to provide subnational accounting of global N 2 O emissions from croplands. We estimate 0.66 Tg of N 2 ON direct global emissions circa 2000, with 50% of emissions concentrated in 13% of harvested area. Compared to estimates from the IPCC Tier 1 linear model, our updated N 2 O emissions range from 20-40% lower throughout Sub-Saharan Africa and Eastern Europe, to >120% greater in some Western European countries. At low N application rates, the weak non-linear response of N 2 O emissions suggests that relatively large increases in N fertilizer application would generate relatively small increases in N 2 O emissions. Since aggregated fertilizer data generate Accepted Article This article is protected by copyright. All rights reserved. underestimation bias in nonlinear models, high-resolution N application data are critical to support accurate N 2 O emissions estimates.
Half of the seafood consumed globally now comes from aquaculture, or farmed seafood. Aquaculture ... more Half of the seafood consumed globally now comes from aquaculture, or farmed seafood. Aquaculture therefore plays an increasingly important role in the global food system, the environment, and human health. Traditionally, aquaculture feed has contained high levels of wild fish, which is unsustainable for ocean ecosystems as demand grows. The aquaculture industry is shifting to crop-based feed ingredients, such as soy, to replace wild fish as a feed source and allow for continued industry growth. This shift fundamentally links seafood production to terrestrial agriculture, and multidisciplinary research is needed to understand the ecological and environmental health implications. We provide basic estimates of the agricultural resource use associated with producing the top five crops used in commercial aquaculture feed. Aquaculture's environmental footprint may now include nutrient and pesticide runoff from industrial crop production, and depending on where and how feed crops are p...
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