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Water-related risks
Published in François Guerquin, Ahmed Tarek, Mi Hua, Tetsuya Ikeda, Vedat Özbilen, Marlies Schuttelaar, World Water actions, 2010
François Guerquin, Ahmed Tarek, Mi Hua, Tetsuya Ikeda, Vedat Özbilen, Marlies Schuttelaar
Natural meteorological and hydrological cycles are characterized by extreme events in both the short and the long term. Humanity has found no means of controlling these extremes and instead seeks to manage the risks that arise as best it can. In the context of this chapter risks refers to water-related disasters resulting from climate variability and change. The natural hazards—floods, droughts, landslides, typhoons, and the like—are largely a consequence of climate variability; climate change is likely to increase their occurrence and intensity. There are also human-induced hazards—such as water pollution and adverse effects from inadequate design, operation, and maintenance of infrastructure (key terms are defined in box 5.1). (This chapter does not deal with the risks arising from water-related diseases, which are covered in chapter 9.)
Water option contracts for climate change adaptation in Santiago, Chile
Published in Water International, 2018
Sebastián Vicuña, Marina Gil, Oscar Melo, Guillermo Donoso, Pablo Merino
Although the potable water system of Santiago has been designed to maintain high levels of service (considering both continuity and quality), it is subject to significant threats from climate variability, climate change and population growth. Studies indicate that climate change could reduce the annual flows in the Maipo River by 10–40% (Meza et al., 2014). They anticipate periods of minimum water flow of between one and four weeks, depending on the scenario under consideration. These projected impacts are related to the predicted increases in temperature and reductions in rainfall that are already observed in the region (Vicuna, Alvarez, Melo, Dale, & Meza, 2014). For the Maipo basin, the study by Meza et al. (2014) shows that future changes in climatic conditions range between −20% to 0 and −40% to −10% change in precipitation for an early (2010–2040) and late (2070–2100) time period, respectively, and between 0.5–1 °C and 1.5–3.5 °C increase in temperature for the two time periods, considering uncertainty in models and emission scenarios. The hydrologic signature of these climatic scenarios show a change in water availability similar in magnitude to the change in precipitation, but also the increase in temperature translates into an earlier hydrograph timing on the order of 5 to 30 days, depending on the time period and emission scenario.
Diagnosis of water crises in the metropolitan area of São Paulo: policy opportunities for sustainability
Published in Urban Water Journal, 2018
Besides the seasonal variation, our results showed an increase in temperature and precipitation changes compared to historical data. A large number of studies have detected changes in precipitation extremes in South America and the MASP, associated with increasing mean temperatures and long dry periods (Caesar et al. 2011; Marengo, Valverde, and Obregon 2013). It can be related to natural climatic changes, ENSO Oscillation and with land-use and land cover changes, especially the urban growth and deforestation (Marengo, Valverde, and Obregon 2013; Nobre et al. 2009; Obregón, Marengo, and Nobre 2014). Urban areas and megacities in Latin America are hotspots of vulnerability to floods, heat waves, landslides and other hazards that climate change is expected to aggravate. Studies on the effects of urbanization growth on climate in the MASP have shown a temperature increase of 3.5 °C or more, which can, therefore, affect convective rainfall (Freitas et al. 2007; Marengo, Valverde, and Obregon 2013). Studies also show that the regional climate variability and change can be associated with Amazon deforestation, because it plays a significant role of global ocean–atmosphere interactions on both local and global climate change (Boers et al. 2014; Nobre et al. 2009).
Comparison of community-based adaptation strategies for droughts and floods in Kenya and the Central African Republic
Published in Water International, 2018
According to Goulden, Conway, and Persechino (2009), impacts and responses to extreme events can be transboundary. They show how far local stategies are appropriate and whether there are opportunities to use another strategy in similar conditions. In general, the magnitude of the disaster’s impact on communities dictates interventions from humanitarian NGOs, governments, or others. According to Conway (2005, p. 2), ‘Adaptive actions can be implemented across all levels of society at local, national, and international scales; but in all cases, actions related to climate variability or change occur within a decision-making framework that encompasses wider socio-economic and political considerations.’ Also, according to Kabat, Schulze, Hellmuth, and Veraart (2002) (as quoted in Goulden et al., 2009), examples of adaptations to climate change in the water sector in developing countries are less documented, perhaps because developing countries have many other pressing issues to tackle and few resources to invest in researching water issues or solutions for improved water management. To be effective, adaptation should fit with the existing management systems and objectives. Goulden et al. (2009) have shown that climate change impacts and other stresses on water resources and changes to flooding risks in future will require adaptation on the behalf of water resource management institutions and water users. This implies that policy makers in both study sites should support local strategies for adaptation. In addition, improvements in climate projections and long-term weather forecasts offer potential for reducing economic losses (or increasing economic gains) associated with climate change. More specifically, improvements in the ability to use such forecasts to inform management strategies would enhance water users’ confidence in regional forecasts, and their ability to efficiently prepare for and adapt to water resource management challenges in future (Adams & Peck, 2008).