OECD Observer
Stormy waters

Climate change is, to a large extent, water change. Water is the predominant channel through which the impact of climate change will be felt. More torrential rains, floods and droughts can be expected in many parts of the world. Not only that–climate change is reshaping the future for freshwater on the planet. 

Water and Climate Change Adaptation, Policies to Navigate Uncharted Waters, part of the OECD Studies on Water series, sets out the challenges facing freshwater resources in a changing climate, and provides policy guidance on how to navigate this new “waterscape”.

Some climate change is unavoidable, regardless of future greenhouse gas emissions, and this has already had a significant impact. Changing precipitation patterns are shifting rainy seasons and affecting the timing and quantity of melt water from snowpack and glaciers. In many cases, this has an impact on flood protection, water storage, urban drainage, water supply and treatment, making them more costly. Shifts in extremes are likely to create a bigger challenge for climate change adaptation than shifts in averages. That means ever severer weather. These shifts are also likely to drive up the costs of adapting water infrastructure. Freshwater ecosystems and the services they provide are especially vulnerable.

Climate change is also projected to influence when and where it rains, with some regions becoming wetter, others drier. In general, regions with high rainfall are projected to receive even more precipitation, the report suggests, while arid and semi-arid regions are projected to become drier. More frequent and intense rain will increase erosion and sediment loads in rivers, lakes and coastal zones, while reducing water quality. In arid and semi-arid regions, any reduction in rainfall has serious implications for rivers and lakes, even causing them to dry up, as in the case of Lake Chad. Many of these areas, which include the Mediterranean basin, the western parts of the US, southern Africa, and north-eastern Brazil, are particularly vulnerable to the impact of climate change and are expected to suffer a drop in water resources.

Water and Climate Change Adaptation: Policies to Navigate Uncharted Waters, in OECD Studies on Water series, OECD Publishing. 

See also www.oecd.org/water 

©OECD Observer No 296, Q3 2013