Lessons from FACE: CO<sub>2</sub> Effects and Interactions with Water, Nitrogen and Temperature

Here we present the results from an intercomparison of multiple global gridded crop models (GGCMs) within the framework of the Agricultural Model Intercomparison and Improvement Project and the Inter-Sectoral Impacts Model Intercomparison Project. Results indicate strong negative effects of climate change, especially at higher levels of warming and at low latitudes; models that include explicit nitrogen stress project more severe impacts. Across seven GGCMs, five global climate models, and four representative concentration pathways, model agreement on direction of yield changes is found in many major agricultural regions at both low and high latitudes; however, reducing uncertainty in sign of response in mid-latitude regions remains a challenge. Uncertainties related to the representation of carbon dioxide, nitrogen, and high temperature effects demonstrated here show that further research is urgently needed to better understand effects of climate change on agricultural production and to devise targeted adaptation strategies.food security | AgMIP | ISI-MIP | climate impacts | agriculture T he magnitude, rate, and pattern of climate change impacts on agricultural productivity have been studied for approximately two decades. To evaluate these impacts, researchers use biophysical process-based models (e.g., refs. 1-5), agro-ecosystem models (e.g., ref. 6), and statistical analyses of historical data (e.g., refs. 7 and 8). Although these and other methods have been widely used to forecast potential impacts of climate change on future agricultural productivity, the protocols used in previous assessments have varied to such an extent that they constrain crossstudy syntheses and limit the ability to devise relevant adaptation options (9, 10). In this project we have brought together seven global gridded crop models (GGCMs) for a coordinated set of simulations of global crop yields under evolving climate conditions. This GGCM intercomparison was coordinated by the Agricultural Model Intercomparison and Improvement Project (AgMIP; 11) as part of the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP; 12). In order to facilitate analyses across models and sectors, all global models are driven with consistent biascorrected climate forcings derived from the Coupled Model Intercomparison Project Phase 5 (CMIP5) archive (13). The objectives are to (i) establish the range of uncertainties of climate change impacts on crop productivity worldwide, (ii) determine key differences in current approaches used by crop modeling groups in global analyses, and (iii) propose improvements in GGCMs and in the methodologies for future intercomparisons to produce more reliable assessments.We examine the basic patterns of response to climate across crops, latitudes, time periods, regional temperatures, and atmospheric carbon dioxide concentrations [CO 2 ]. In anticipation of the wider scientific community using these model outputs and the expanded application of GGCMs, we introduce these models and present guidelines for their pract...

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“…How the GGCMs handle these factors and their interactions with nutrient availability (especially N) has significant impacts on the results (41).…”

Section: Model Processesmentioning

confidence: 99%

Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison

Rosenzweig

Elliott

Deryng

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

1,843

1,367

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“…(1) As mentioned before, there is an active discussion about this question (Long et al, 2006;Fleisher et al, 2011;Kimball, 2011;McGrath and Lobell, 2013 (Kimball, 2011). While it is hard to quantify the difference, especially given the heterogeneous structure of the research area, it could be assumed that yields achieved under adapted [CO 2 ] are still overestimated in this study.…”

Section: Discussionmentioning

confidence: 99%

“…FACE experiments are situated in open air, within the natural atmosphere. [CO 2 ] is emitted through tubes around the plant samples and regulated to the desired level (Kimball et al, 2002;Kimball, 2011). Tests in secluded SPAR (Soil-Plant-AtmosphereResearch) chambers produce results that mostly surpassed those in FACE experiments under near natural conditions.…”

Section: Introductionmentioning

confidence: 99%

“…N), water supply and temperature as well as their interaction are considered, as they have a major impact on the final result. If, for example, the water availability is accounted for, even C 4 -plants are then affected by an elevated [CO 2 ], as they do not react under normal or optimal conditions to more [CO 2 ] but do so if their water supply is limited (Kimball, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Atmospheric CO2 fertilization effects on biomass yields of 10 crops in northern Germany

Degener

2015

Front. Environ. Sci.

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The quality and quantity of the influence that atmospheric CO 2 has on crop growth is still a matter of debate. This study's aim is to estimate if [CO 2 ] will have an effect on biomass yields at all, to quantify and spatially locate the effects and to explore if an elevated photosynthesis rate or water-use-efficiency is predominantly responsible. This study uses a numerical carbon-based crop model (BioSTAR) to estimate biomass yields within the administrative boundaries of Niedersachsen in Northern Germany. Ten crops are included (winter grains: wheat, barley, rye, triticale-early, medium, late maize variety-sunflower, sorghum, spring wheat), modeled annually for the entire twenty-first century on 91,014 separate sites. Modeling was conducted twice, once with an annually adapted [CO 2 ] concentration according to the SRES-A1B scenario and once with a fixed concentration of 390 ppm to separate the influence of [CO 2 ] from that of the other input variables. Rising [CO 2 ] concentrations will play a central role in keeping future yields of all crops above or around today's level. Differences in yields between modeling with fixed or adapted [CO 2 ] can be as high as 60% toward the century's end. Generally, yields will increase when [CO 2 ] rises and decline when it is kept constant. As C 4 -crops are equivalently affected it is presumed that an elevated efficiency in water use is the main responsible factor for all plants.

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“…The direct impact of rising atmospheric [CO 2 ] concentration on plants includes increase in photosynthetic rate [4]- [6], growth [7]- [9], reduction in nutrient concentration of plants [10] [11], reduction in leaf nitrogen concentration [12]- [14], increased C:N ratio [15] [16] and increased flowering and fruiting [15]- [21], and yield of agricultural crops [2] [22] [23], and is also expected to increase water use efficiency of crops [2] [4]. Productivity of most agricultural crops increases under elevated [CO 2 ] is in the range of 15% to 41% for C3 crops and 5% to 10% for C4 crops [2] [22] [23].…”

Section: Introductionmentioning

confidence: 99%

Elevated Carbon Dioxide and Soil Moisture on Early Growth Response of Soybean

Madhu¹,

Hatfield²

2015

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Lessons from FACE: CO₂ Effects and Interactions with Water, Nitrogen and Temperature

Cited by 46 publications

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Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison

Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison

Atmospheric CO2 fertilization effects on biomass yields of 10 crops in northern Germany

Elevated Carbon Dioxide and Soil Moisture on Early Growth Response of Soybean

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Lessons from FACE: CO2 Effects and Interactions with Water, Nitrogen and Temperature

Cited by 46 publications

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Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison

Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison

Atmospheric CO2 fertilization effects on biomass yields of 10 crops in northern Germany

Elevated Carbon Dioxide and Soil Moisture on Early Growth Response of Soybean

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Product

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Lessons from FACE: CO₂ Effects and Interactions with Water, Nitrogen and Temperature