Fernando Jaramillo & Georgia Destouni, Stockholm University
This global study investigated the effects of flow regulation and irrigation using hydroclimatic observations from 1901-2008 in 100 hydrological basins situated throughout the world, covering about 35% of the global land area (excluding Antarctica)
For these basins, the results show that both flow regulation and irrigation lead to an increase in relative evapotranspiration, while flow regulation leads also to a decrease in temporal runoff variability. Evapotranspiration changes due to flow regulation and irrigation were found to be greater than changes due to climate change.
Comparing the time periods 1901-1954 and 1955-2008, the increase in evapotranspiration due to flow regulation and irrigation was 3563 ± 979 km3/year. These new results increase a recent estimate of the global water footprint for humanity by at least 18%, to 10,688 ± 979 km3/year. Also, it implies that human water consumption has passed beyond a proposed planetary boundary.
These results show how local water use has global impacts. Furthermore, given their impacts, the effects of flow regulation and irrigation should be accounted for in Earth-system modelling.
Jaramillo F, Destouni G, 2015. Local flow regulation and irrigation raise global human water consumption and footprint. Science 350(6265), 1248, doi: 10.1126/science.aad1010.
This study investigated changes in water temperature from 66 northern European cold-water springs during 1968-2012. The water temperature in most of these springs had increased by a statistically significant amount. Future estimates of the increase in water temperature in these springs due to climate change vary from 0.67 °C to 5.94 °C, depending on the climate scenario. High temperature increases are likely to change the ecology of these cold-water ecosystems, causing extinction of endemic specialist species and increases in the number of generalist species. It is possible that even just a small increase (of about 1°C) in water temperature in springs could cause extinction of endemic species and lead to regional-scale homogenization of ecosystems in northern European headwater streams.
Jyväsjärvi J, Marttila H, Rossi PM, Ala-Aho P, Olofsson B, Nisell J, Backman B, Ilmonen J, Virtanen R, Paasivirta L, Britschgi R, Kl ve B, Muotka T, 2015. Climate-induced warming imposes a threat to north European spring ecosystems. Global Change Biology 21, 4561-4569, doi: 10.1111/gcb.13067
Principal investigator: Georgia Destouni, Stockholm University
Read the KLIV Synthesis Report: Needs and means to advance science, policy and management understanding of the freshwater system – A synthesis report
The whole KLIV group has during 2013 worked on a sub-project for developing a general conceptualization framework for environmental-climate change interactions and change propagation through the whole coupled human-natural system of water on land – this work has been led by Georgia Destouni and is planned to be finalized and submitted for publication in 2014. Continue reading Needs and means to advance science, policy and management understanding of the freshwater system