Quantitative assessment of climate change and human impacts on long‐term hydrologic response: a case study in a sub‐basin of the Yellow River, China

Abstract

In this study we developed an impact factor formula (IFF) to quantitatively attribute separately the impacts of climate change and local human activities on hydrological response (i.e. run-off) in a sub-basin of Yellow River for the period 1950-2000. Using the daily climatic data, we first calibrated and verified the variable infiltration capacity (VIC) hydrological model to the baseline period 1955-1970. Then we developed the basin's natural run-off for the following three decades using the VIC model without considering local human impacts, as the VIC model is benchmarked by the 1960's hydrological regime.On the basis of observed precipitation, run-off and reconstructed natural run-off data from 1971 to 2000, we quantified their long-term trend, decadal and annual variations. Using daily climatic observations, we showed that the precipitation and run-off have decreased from the baseline decade, the 1960s, indicating a drier hydrological regime for recent decades. We further applied the IFF to quantitatively attribute separately the impacts of reduced precipitation and increased temperatures from climate change and then of local human activities on hydrological run-off response. It was found that climate change has a greater impact than human activities on the basin's run-off for the three consecutive decades. The pCC (percentage change of run-off due to climate change impact) is found to be 89% followed by 66% and 56% in 1970s, 1980s and 1990s, respectively. Over the decades, pHA (percentage change of run-off due to human activities) has continuously increased from 11% to 44%. If the trend continues, in future, the pHA is going to outweigh pCC in this basin. This study provides a quantitative assessment methodology for water resources managers to understand the changing process of the hydrological cycle and attribute its causative factors in a sub-basin of the Yellow River.

Effects of urbanization and climate change on surface runoff of the Brussels Capital Region: a case study using an urban soil–vegetation–atmosphere‐transfer model

“…It is widely recognized that these predicted temperature changes have the potential to produce changes in the temporal and spatial distribution of precipitation, increasing the frequency of storm intensities and flooding, causing more frequent droughts and decreasing annual snowfall (Kundewicz et al, 2007). Many studies have evaluated the effect of either urbanization (Smith et al, 2002;Chang, 2007;Yang et al, 2010) or climate changes (Woldeamlak et al, 2007;SanchezGomez et al, 2009) on watershed runoff; however, the combined effects of these two effects using simulation models have been coming under increased scrutiny in recent years (Hejazi and Moglen, 2008;Cuo et al, 2009;Franczyk and Chang, 2009;Hejazi and Markus, 2009;Wang et al, 2010). Conceptual hydrological models are driven by weather data time series such as precipitation, temperature and soil moisture.…”

A framework for evaluating regional hydrologic sensitivity to climate change using archetypal watershed modeling

“…Numerous reports by the Intergovernmental Panel on Climate Change (1992, 1995, 2001 and 2007) predict global mean temperatures to increase from 1.4 to 5.8 • C over the next 100 yr. Atmospheric warming will impact regional rainfall patterns, snow accumulation and melt, river runoff, soil moisture storage and plant water availability (McCabe and Wolock, 2008;Costa and Soares, 2009;Githui et al, 2009;Hidalgo et al, 2009;Kunkel et al, 2009;Clark, 2010;Wang et al, 2010). There is significant motivation to perform regional studies investigating the effects of climate change on local water resources, especially in water-stressed regions (Mote et al, 2005;CCCC, 2006;Aragão et al, 2007;Westerling and Bryant, 2008).…”

Hydroclimatology

“…This indicates that natural processes account for much of the hydroclimatic change, but there has been an increase in the human impact (from 11% to 44%). Wang et al (2010) point to an impending crisis in water supply in the heavily populated Yellow river basin.All of these special issue papers demonstrate the non-stationarity of hydrometeorological processes and that climate variability and change can be identified over large managed river basins. They also present new methodologies that can be replicated in future studies in other regions of the world.…”

“…However, this relationship was weak during the 1970s climate shift. Finally, Wang et al (2010) developed an impact factor formula (IFF) to separate human activity from climate change in a sub-basin of the Yellow river. A trend towards drying (reduced precipitation and run-off) was observed in the second half of the 20 th century, and a hydrologic model reconstructed 89% of this trend in the 1970s as compared to 56% in the 1990s.…”

“…This indicates that natural processes account for much of the hydroclimatic change, but there has been an increase in the human impact (from 11% to 44%). Wang et al (2010) point to an impending crisis in water supply in the heavily populated Yellow river basin.…”