Evapotranspiration and soil water content in a scrub‐oak woodland under carbon dioxide enrichment

Hungate, Bruce A.; Reichstein, Markus; Dijkstra, Paul; Johnson, David P.; Hymus, Graham J.; Tenhunen, John; Hinkle, C. Ross; Drake, Bert G.

doi:10.1046/j.1365-2486.2002.00468.x

Cited by 110 publications

(78 citation statements)

References 48 publications

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“…The magnitude of this physiological forcing depends on the degree of stomatal control over evapotranspiration [23]. A number of field-based experiments have demonstrated the reduction of evapotranspiration in a CO 2 enriched environment [24][25][26]. Reduced evapotranspiration allows a relatively higher proportion of water to form runoff, a renewable water resource.…”

Section: Co 2 Fertilisation and Physiological Forcingmentioning

confidence: 99%

The Impact of Climate, CO2 and Population on Regional Food and Water Resources in the 2050s

et al. 2013

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Population growth and climate change are likely to impact upon food and water availability over the coming decades. In this study we use an ensemble of climate simulations to project the implications of both these drivers on regional changes in food and water. This study highlights the dominant effect of population growth on per capita resource allocation over climate induced changes in our model projections. We find a strong signal for crop yield reductions due to climate change by the 2050s in the absence of CO 2 fertilisation effects. However, when these additional processes are included this trend is reversed. The impacts of climate on water resources are more uncertain. Overall, we find reductions in the global population living in water stressed conditions due to the combined effects of climate and CO 2 . Africa is a key region where projected decreases in runoff and crop productivity from climate change alone are potentially reversed when CO 2 fertilisation effects are included, but this is highly uncertain. Plant physiological response to increasing atmospheric CO 2 is a major driver of the changes in crop productivity and water availability in this study; it is poorly constrained by observations and is thus a critical uncertainty.

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Section: Co 2 Fertilisation and Physiological Forcingmentioning

confidence: 99%

The Impact of Climate, CO2 and Population on Regional Food and Water Resources in the 2050s

et al. 2013

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“…A decrease in canopy transpiration tends to reduce evapotranspiration (the sum of canopy evaporation, canopy transpiration, and soil evaporation), triggering changes in atmospheric water vapor and clouds, and affecting surface radiative fluxes, thus producing changes to temperature and the water cycle. This driver of climate change, referred to as "CO 2 -physiological forcing," has been detected in both field experiments (4,5) and climate modeling studies (3,(6)(7)(8)(9)(10)(11).…”

mentioning

confidence: 93%

Importance of carbon dioxide physiological forcing to future climate change

Cao

Bala

Caldeira

et al. 2010

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

274

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An increase in atmospheric carbon dioxide (CO 2 ) concentration influences climate both directly through its radiative effect (i.e., trapping longwave radiation) and indirectly through its physiological effect (i.e., reducing transpiration of land plants). Here we compare the climate response to radiative and physiological effects of increased CO 2 using the National Center for Atmospheric Research (NCAR) coupled Community Land and Community Atmosphere Model. In response to a doubling of CO 2 , the radiative effect of CO 2 causes mean surface air temperature over land to increase by 2.86 AE 0.02 K (AE1 standard error), whereas the physiological effects of CO 2 on land plants alone causes air temperature over land to increase by 0.42 AE 0.02 K. Combined, these two effects cause a land surface warming of 3.33 AE 0.03 K. The radiative effect of doubling CO 2 increases global runoff by 5.2 AE 0.6%, primarily by increasing precipitation over the continents. The physiological effect increases runoff by 8.4 AE 0.6%, primarily by diminishing evapotranspiration from the continents. Combined, these two effects cause a 14.9 AE 0.7% increase in runoff. Relative humidity remains roughly constant in response to CO 2 -radiative forcing, whereas relative humidity over land decreases in response to CO 2 -physiological forcing as a result of reduced plant transpiration. Our study points to an emerging consensus that the physiological effects of increasing atmospheric CO 2 on land plants will increase global warming beyond that caused by the radiative effects of CO 2 .global warming | runoff | evapotranspiration | hydrological cycle | plant stomata I ncreased atmospheric CO 2 content affects global climate not only through its greenhouse radiative effect, but also through its effect on plant physiology. Plant stomata open less widely under elevated CO 2 concentrations, leading to reduced plant transpiration (1-3). A decrease in canopy transpiration tends to reduce evapotranspiration (the sum of canopy evaporation, canopy transpiration, and soil evaporation), triggering changes in atmospheric water vapor and clouds, and affecting surface radiative fluxes, thus producing changes to temperature and the water cycle. This driver of climate change, referred to as "CO 2 -physiological forcing," has been detected in both field experiments (4, 5) and climate modeling studies (3,(6)(7)(8)(9)(10)(11).In this study, we examine the climate effect of CO 2 -physiological forcing using a coupled global atmosphere-land surface model (12,13). While previous studies have looked at the response of temperature and runoff to CO 2 -physiological forcing, the focus of this study is to examine the nature of climate response to CO 2 -physiological forcing in terms of both magnitude and pattern, and contrast it with the effect of CO 2 -radiative forcing. Most previous modeling studies on the climate effect of CO 2 -physiological forcing (6-11) were performed within the modeling framework of the Met office Hadley Center models using the "MOSES" scheme (7) as...

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“…Elevated CO 2 generally stimulates C 3 -type photosynthesis (Curtis 1996), but it is uncertain how enhanced photosynthesis will interact with a variety of other factors that influence plant growth (Körner 2000). Responses of upland plants to elevated CO 2 can be constrained by nutrient availability (Zak et al 1999), water availability (Loustau et al 2001, Hungate et al 2002, and tropospheric ozone concentration (Dickson et al 1998); very little is known about factors that interact with elevated CO 2 in wetlands. Interactions with elevated CO 2 must be addressed because it is clear that elevated CO 2 will be accompanied by global warming and a variety of other environmental changes (Ramaswamy et al 2001), and these effects are often non-additive (Pendall et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Flooding constraints on tree (Taxodium distichum) and herb growth responses to elevated CO2

2005

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Elevated CO 2 generally stimulates C 3 -type photosynthesis, but it is unclear how an increase in CO 2 assimilation will interact with other factors that influence plant growth. In wetlands, the response of plants to elevated CO 2 will interact with soil saturation, particularly in forested wetlands where soil saturation is a strong regulator of plant productivity. We performed a four-month experiment to determine whether elevated CO 2 and flooding interact to influence the growth of a flood-tolerant tree (Taxodium distichum) and a flood-tolerant herbaceous emergent macrophyte (Orontium aquaticum). Seedlings were grown in glasshouses at two CO 2 levels (350 and 700 L L Ϫ1 ) crossed with two water depths (5 cm above and Ն5 cm below the soil surface). We hypothesized that elevated CO 2 would increase photosynthesis regardless of water depth and species; however, we also expected flooding to prevent elevated CO 2 from increasing the growth of the tree species due to O 2 limitation or other physiological stresses associated with reduced soil environments. We found that elevated CO 2 increased whole-plant photosynthesis in both species regardless of the flooding treatment. For T. distichum, this higher photosynthetic rate resulted in greater biomass only in the non-flooded treatment. This result suggests that some factor related to flooding constrained the biomass response of the flooded woody plants to elevated CO 2 . In contrast, elevated CO 2 increased O. aquaticum biomass regardless of the flooding regime, perhaps because it occurs in wetter landscape positions than T. distichum and is less sensitive to flooding. We conclude that flooding may limit plant growth responses to elevated CO 2 , particularly in woody plant species.

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Evapotranspiration and soil water content in a scrub‐oak woodland under carbon dioxide enrichment

Cited by 110 publications

References 48 publications

The Impact of Climate, CO2 and Population on Regional Food and Water Resources in the 2050s

The Impact of Climate, CO2 and Population on Regional Food and Water Resources in the 2050s

Importance of carbon dioxide physiological forcing to future climate change

Flooding constraints on tree (Taxodium distichum) and herb growth responses to elevated CO2

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