Impact of Climate change on tropical terrestrial water use efficiency

2020 ◽  
Author(s):  
Shweta Kumari ◽  
Mark A Adams
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Water Use Efficiency ◽  
Eddy Covariance ◽  
Water Use ◽  
Tree Ring ◽  
Tropical Regions ◽  
The North ◽  
Tree Ring Data ◽  
Use Efficiency

<p>Variability in precipitation and temperature are key markers of climate change. Extreme events like heat waves, droughts, frosts, wind storms, flooding rains and fires greatly affect ecosystem and terrestrial carbon balance. Tropical regions in particular make strong contributions to the global carbon cycle and are the focus of our research. Our initial analysis confirmed the long-known pattern of large variability in rainfall in the tropical southern hemisphere (i.e. between the Tropic of Capricorn and the Equator) w.r.t. the north, with less variation in temperature between the hemispheres. In the follow-up analysis, we focus on exchanges of carbon and water and water use efficiency, based on 39 eddy covariance flux sites which represent 25 years of data across the tropics. Our working hypothesis is that long-term increases in temperature and significant changes (+/-) in rainfall will be reflected in changes in water use efficiency and cropping period, albeit with greater spatial and temporal variation in the south than in the north. We are also investigating relationships between water use efficiency of tropical regions calculated using eddy covariance flux data, with that calculated using tree ring data. We seek to combine methodologies that can help drive our understanding of the impact of climate change on water use efficiency of tropical regions.</p><p><strong><span>Keywords: </span></strong><span>Eddy covariance, Tropics, Water use efficiency, Carbon cycle, Tree ring data</span></p>

scholarly journals 20th-century changes in carbon isotopes and water-use efficiency: Tree-ring based evaluation of the CLM4.5 and LPX-Bern models

2016 ◽  
Author(s):  
Kathrin M. Keller ◽  
Sebastian Lienert ◽  
Anil Bozbiyik ◽  
Thomas F. Stocker ◽  
Olga V. Churakova ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
20Th Century ◽  
Water Use ◽  
Tree Ring ◽  
Dynamic Global Vegetation Model ◽  
Isotopic Discrimination ◽  
Tree Ring Data ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Abstract. Measurements of the stable carbon isotope ratio (δ13C) on annual tree rings offer new opportunities to evaluate mechanisms of variations in photosynthesis and stomatal conductance under changing CO2 and climate, especially in conjunction with process-based biogeochemical model simulations. The isotopic discrimination is indicative of the ratio between the CO2 partial pressure in the intercellular cavities and the atmosphere (ci / ca) and of the ratio of assimilation to stomatal conductance, termed intrinsic water-use efficiency (iWUE). We performed isotope-enabled simulations over the industrial period with the land biosphere module (CLM4.5) of the Community Earth System Model and the LPX-Bern dynamic global vegetation model. Results for C3 tree species show good agreement with a global compilation of δ13C measurements on leaves, though modeled 13C discrimination by C3 trees is smaller in arid regions than measured. A compilation of seventy-six tree-ring records, mainly from Europe, boreal Asia, and western North America, suggest on average small 20th-century changes in isotopic discrimination and an increase in iWUE of about 27 % since 1900. LPX-Bern results match these century-scale reconstructions, supporting the idea that the physiology of stomata has evolved to optimize trade-offs between carbon gain by assimilation and water loss. In contrast, CLM4.5 simulates an increase in discrimination and in turn a change in iWUE that is almost twice as large as revealed by the tree-ring data. Factorial simulations show that these changes are mainly in response to rising atmospheric CO2. The results suggest that the down-regulation of ci / ca and of photosynthesis by nitrogen limitation is possibly too strong in the standard setup of CLM4.5 or there may be more fundamental problems associated with the prescribed relationship between conductance and assimilation.

Climate change is expected to increase yield and water use efficiency of wheat in the North China Plain

2019 ◽  
Vol 222 ◽  
pp. 193-203 ◽  
Author(s):  
Muhammad Adil Rashid ◽  
Mohamed Jabloun ◽  
Mathias Neumann Andersen ◽  
Xiying Zhang ◽  
Jørgen Eivind Olesen
Keyword(s):  
Climate Change ◽  
Water Use Efficiency ◽  
Water Use ◽  
North China Plain ◽  
North China ◽  
The North ◽  
The North China Plain ◽  
Use Efficiency

scholarly journals 20th century changes in carbon isotopes and water-use efficiency: tree-ring-based evaluation of the CLM4.5 and LPX-Bern models

2017 ◽  
Vol 14 (10) ◽  
pp. 2641-2673 ◽  
Author(s):  
Kathrin M. Keller ◽  
Sebastian Lienert ◽  
Anil Bozbiyik ◽  
Thomas F. Stocker ◽  
Olga V. Churakova (Sidorova) ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
20Th Century ◽  
Water Use ◽  
Tree Ring ◽  
Dynamic Global Vegetation Model ◽  
Isotopic Discrimination ◽  
Tree Ring Data ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Abstract. Measurements of the stable carbon isotope ratio (δ13C) on annual tree rings offer new opportunities to evaluate mechanisms of variations in photosynthesis and stomatal conductance under changing CO2 and climate conditions, especially in conjunction with process-based biogeochemical model simulations. The isotopic discrimination is indicative of the ratio between the CO2 partial pressure in the intercellular cavities and the atmosphere (ci∕ca) and of the ratio of assimilation to stomatal conductance, termed intrinsic water-use efficiency (iWUE). We performed isotope-enabled simulations over the industrial period with the land biosphere module (CLM4.5) of the Community Earth System Model and the Land Surface Processes and Exchanges (LPX-Bern) dynamic global vegetation model. Results for C3 tree species show good agreement with a global compilation of δ13C measurements on leaves, though modeled 13C discrimination by C3 trees is smaller in arid regions than measured. A compilation of 76 tree-ring records, mainly from Europe, boreal Asia, and western North America, suggests on average small 20th century changes in isotopic discrimination and in ci∕ca and an increase in iWUE of about 27 % since 1900. LPX-Bern results match these century-scale reconstructions, supporting the idea that the physiology of stomata has evolved to optimize trade-offs between carbon gain by assimilation and water loss by transpiration. In contrast, CLM4.5 simulates an increase in discrimination and in turn a change in iWUE that is almost twice as large as that revealed by the tree-ring data. Factorial simulations show that these changes are mainly in response to rising atmospheric CO2. The results suggest that the downregulation of ci∕ca and of photosynthesis by nitrogen limitation is possibly too strong in the standard setup of CLM4.5 or that there may be problems associated with the implementation of conductance, assimilation, and related adjustment processes on long-term environmental changes.

scholarly journals Open Intellectual Property Models for Plant Innovations in the Context of New Breeding Technologies

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1218
Author(s):  
Michael A. Kock
Keyword(s):  
Climate Change ◽  
Food Security ◽  
Intellectual Property ◽  
Water Use Efficiency ◽  
Water Use ◽  
Open Innovation ◽  
Climate Resilience ◽  
Use Efficiency ◽  
Mitigate Climate Change ◽  
New Breeding Technologies

Plant related innovations are critical to enable of food security and mitigate climate change. New breeding technologies (NBTs) based on emerging genome editing technologies like CRISPR/Cas will facilitate “breeding-by-editing” and enable complex breeding targets—like climate resilience or water use efficiency—in shorter time and at lower costs. However, NBTs will also lead to an unprecedented patent complexity. This paper discusses implications and potential solutions for open innovation models.

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