Impacts of elevated CO 2 , climate change and their interactions on water budgets in four different catchments in Australia

Abstract

Future water availability is affected directly by the effects of climate change on 16 water loss through evapotranspiration (ET) GCMs representing a period centred on 2050s was projected and then downscaled to the 27 study catchments. The future CO 2 concentration (i.e., eCO 2 ) at 2050 was projected to be 28 550ppm. Results from this study show eCO 2 increases canopy leaf area index (LAI) in all 29 four catchments and increases ET and decreases runoff in the water limited forest catchment 30 and the two grassland catchments, but reduces ET and increases runoff in the energy-limited 31 forest catchment. The effects of future climate on canopy LAI, ET and total runoff were 32 opposing in sign to those of eCO 2 for all four catchments. Our results also suggest that the 33 interactions between the direct and indirect effects on ET are relatively strong in the two 34 grassland catchments but relatively weak in the two forest catchments, possibly because the 35 deep-rooted forest system can utilize more available soil water than grasslands. Interactions 36 on runoff were relatively strong in the two water-limited catchments but weak in the two 37 energy-limited catchments, possibly because ET in the water-limited ecosystems are mainly 38 constrained by water and arid ecosystems have higher water use efficiency. This study 39 highlights that failure to account for impacts of eCO 2

Future shift of the relative roles of precipitation and temperature in controlling annual runoff in the conterminous United States

“…Land cover, LAI, and soil are important controls on catchment water balance and R sensitivity to climate change (Zhang et al, 2001;Bosch and Hewlett, 1982;Cheng et al, 2014). This study specifically focused on evaluating the separate and combined effects of changing climates on R within a static land cover/land use.…”

Attributing regional trends of evapotranspiration and gross primary productivity with remote sensing: a case study in the North China Plain

“…Separating the contributions of climatic change, CO 2 enrichment, and human activities to the long-term trends of water and carbon cycles is critical for assessment of ecosystem responses and resilience to environmental changes. Some researchers have explored the relative contributions of climate change and vegetation dynamics to changes in global land surface evapotranspiration and river runoff (Betts et al, 2007;Piao et al, 2007;Alkama et al, 2010;Liu et al, 2012;Chen et al, 2014Chen et al, , 2015Banger et al, 2015), but the conclusions are still inconsistent. Climate change dominated the interannual variability of ET, while land use changes and agricultural practices and techniques exerted more discernable effects on the water cycle in the long term .…”

Forest Management Challenges for Sustaining Water Resources in the Anthropocene

“…We should also expect that watershed ecosystems will continue to respond to global change in complex ways characterized as nonlinear and threshold response, some of which may be novel and unprecedented. For example, climate warming may increase evaporation potential but the rise of atmospheric CO 2 concentration may increase water use efficiency thus reduce water use by trees at the leaf level for some species [76]. The end results on hydrology and ecosystem dynamics at the scale of a watershed with mixed land use and variable precipitation patterns can be unpredictable [31].…”