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Climate Action 2009-2010


ECOSYSTEM SERVICES © ?????????????? Climate action for water quality WATER 176 Sabrina barker, consultant, unEP global EnvironmEnt monitoring systEm (gEms/watEr ProgrammE) Public awareness about many climate change issues – carbon footprints, green house gas emissions, global warming and others – has improved significantly in the past few years. For example, people are increasingly concerned about the future of small islands, polar bears and sea level rise caused by increasing global temperatures. What is less known, but just as important, are the effects that climate change can have on our inland water supplies. While some effects may be beneficial, others may be detrimental to both aquatic ecosystems and to human well-being. INTRODUCTION Changes in average temperature, precipitation levels and rising sea level are expected to occur over the next few decades, partly in response to large-scale atmospheric events such as El Niño and the North Atlantic Oscillation. It is anticipated that precipitation will increase at higher latitudes and decrease at lower latitudes. In areas with more frequent and intense precipitation, more pollution and sediments will be flushed into lakes and rivers, thereby degrading water quality. Consequently, more resources will be needed to treat water for drinking, irrigation, as well as industrial uses. However, in other areas, higher water flows could dilute pollutions, causing water quality to improve. Further, increased flooding associated with more frequent and intense precipitation could damage or overwhelm municipal treatment facilities, mine tailing ponds, or landfills, and increase the risk of contamination. Areas of standing water could provide breeding grounds for insect and microbial pathogens, increasing the risk of disease. In regions that undergo periods of drought or receive lower than average annual rainfall, lower river flows will concentrate pollutants and increase salinity, as the dilution effects of watercourses will be reduced. “ Over the last century, fifty per cent of species are estimated to have responded in some way to climate change “ Sea level rise may also affect water quality because increased salinity in coastal rivers and bays and cause saltwater intrusion, moving saline water into fresh groundwater resources in coastal areas. VISIT: WWW.CLIMATEACTIONPROGRAMME.ORG

ECOSYSTEM SERVICES Figure 1. Mean annual surface water lake temperatures over time for long-term monitoring stations in Europe, Asia, Africa, and the Americas. Lines are ‘best fit’ linear regressions. Source: UNEP GEMS/Water Programme WATER-RELATED CONSEQUENCES OF CLIMATE CHANGE Temperature increases, along with changes in the frequency and duration of precipitation are expected to alter the intensity, frequency and duration of both floods and droughts. As observed by the Intergovernmental Panel on Climate Change (IPCC), the results for inland water sources will be altered water temperatures, flow regimes and water levels. As shown in Figure 1, long-term data records about lakes around the world indicate significant increases in temperature. See Figure 1. There will also be impacts on aquatic biodiversity. Over the last century, fifty per cent of species are estimated to have responded in some way to climate change. The level of species loss will be directly related to the extent to which we can limit global warming. If we manage to contain global warming to two degrees Celsius, then there will be some species loss but there are conceivable management options for the conservation of global biodiversity. At four degrees Celsius, there will be many species lost, with few management options and enormous financial cost. At the uppermost predictions of around six degrees Celsius temperature rise, the outlook is dire. Many species are sensitive to water temperature, and even marginal changes can drastically affect reproduction of fish and other aquatic organisms. As a result, the Millennium Ecosystem Assessment stressed that climate change is likely to become the dominant direct driver of biodiversity loss by the end of the century. There are significant uncertainties about the relationships of species distribution and climate change, and about species’ abilities to migrate and redistribute. Habitat fragmentation is a key factor affecting the ability of species to respond to climate change, and water sources are often an integral feature of many ecosystems. For scientists to be able to provide accurate and timely predictions and models of how climate change will affect water quality around the world, more data and information are needed. In Climate Change and Water, the IPCC calls for a better understanding and modelling of climate changes related to the hydrological cycle, which in turn requires better and more observational data. Information about the water-related impacts of climate change is inadequate “especially with respect to water quality, aquatic ecosystems and groundwater, including their socio-economic dimensions.” Because of increasing concerns about water quality for human use and ecosystem sustainability, there is an emerging need to assess the impacts of climate change on the quality of inland water resources on a global scale. THE IMPACT ON INLAND WATER RESOURCES For over 30 years, the UN’s GEMS/Water Programme has been a leading source of global water quality data, with more than 3,000 monitoring stations in 100 countries worldwide. The Programme is well positioned to undertake research and assessment activities on WATER 177 VISIT: WWW.CLIMATEACTIONPROGRAMME.ORG