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Energy, Resources and the Environment

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Words on Wednesday: A multi-model analysis of change in potential yield of major crops in China under climate change

Words on Wednesday aims at promoting interesting/fun/exciting publications on topics related to Energy, Resources and the Environment. If you would like to be featured on WoW, please send us a link of the paper, or your own post, at ERE.Matters@gmail.com.

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Yin, Y., Tang, Q., and Liu, X.: A multi-model analysis of change in potential yield of major crops in China under climate change, Earth Syst. Dynam., 6, 45-59, doi:10.5194/esd-6-45-2015, 2015

Abstract:

Climate change may affect crop growth and yield, which consequently casts a shadow of doubt over China’s food self-sufficiency efforts. In this study, we used the projections derived from four global gridded crop models (GGCropMs) to assess the effects of future climate change on the yields of the major crops (i.e., maize, rice, soybean and wheat) in China. The GGCropMs were forced with the bias-corrected climate data from five global climate models (GCMs) under Representative Concentration Pathway (RCP) 8.5, which were made available through the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). The results show that the potential yields of the crops would decrease in the 21st century without carbon dioxide (CO2) fertilization effect. With the CO2 effect, the potential yields of rice and soybean would increase, while the potential yields of maize and wheat would decrease. The uncertainty in yields resulting from the GGCropMs is larger than the uncertainty derived from GCMs in the greater part of China. Climate change may benefit rice and soybean yields in high-altitude and cold regions which are not in the current main agricultural area. However, the potential yields of maize, soybean and wheat may decrease in the major food production area. Development of new agronomic management strategies may be useful for coping with climate change in the areas with a high risk of yield reduction.

The MM of the relative change in the simulated yield of maize (a), rice (b), soybean (c) and wheat (d) with the CO2 effect at the end of the 21st century (2070–2099) compared with the simulated yield in the historical period (1981–2010).

The MM of the relative change in the simulated yield of maize (a), rice (b), soybean (c) and wheat (d) with the CO2 effect at the end of the 21st century (2070–2099) compared with the simulated yield in the historical period (1981–2010).

Words on Wednesday: Global trends in extreme precipitation – climate models versus observations

Words on Wednesday aims at promoting interesting/fun/exciting publications on topics related to Energy, Resources and the Environment. If you would like to be featured on WoW, please send us a link of the paper, or your own post, at ERE.Matters@gmail.com.

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Asadieh, B. and Krakauer, N. Y.: Global trends in extreme precipitation: climate models versus observations, Hydrol. Earth Syst. Sci., 19, 877-891, doi:10.5194/hess-19-877-2015, 2015

Abstract:

Precipitation events are expected to become substantially more intense under global warming, but few global comparisons of observations and climate model simulations are available to constrain predictions of future changes in precipitation extremes. We present a systematic global-scale comparison of changes in historical (1901–2010) annual-maximum daily precipitation between station observations (compiled in HadEX2) and the suite of global climate models contributing to the fifth phase of the Coupled Model Intercomparison Project (CMIP5). We use both parametric and non-parametric methods to quantify the strength of trends in extreme precipitation in observations and models, taking care to sample them spatially and temporally in comparable ways. We find that both observations and models show generally increasing trends in extreme precipitation since 1901, with the largest changes in the deep tropics. Annual-maximum daily precipitation (Rx1day) has increased faster in the observations than in most of the CMIP5 models. On a global scale, the observational annual-maximum daily precipitation has increased by an average of 5.73 mm over the last 110 years, or 8.5% in relative terms. This corresponds to an increase of 10% K−1 in global warming since 1901, which is larger than the average of climate models, with 8.3% K−1. The average rate of increase in extreme precipitation per K of warming in both models and observations is higher than the rate of increase in atmospheric water vapor content per K of warming expected from the Clausius–Clapeyron equation. We expect our findings to help inform assessments of precipitation-related hazards such as flooding, droughts and storms.

HadEX2 observational data versus CMIP5 averaged results of global extreme precipitation in 1901–2010 – annual-maximum daily precipitation map (mm day-1) for (a) HadEX2 and (b) the average of CMIP5 model runs.

HadEX2 observational data versus CMIP5 averaged results of global extreme precipitation in 1901–2010 – annual-maximum daily precipitation map (mm day-1) for (a) HadEX2 and (b) the average of CMIP5 model runs.