Global climate change is a result of the accumulation of greenhouse gases in the atmosphere and scientists around the world now agree this is due of human activity. The repercussions of even a small increase in global temperature are wide reaching as it affects the hydrological cycle which alters the natural frequencies of floods and droughts. The result is an impact on the availability of water, and even though developed and industrialised nations are primarily responsible for the causes of climate change, it is those in the poorest nations who will be affected the most.1

In poor nations some of the most important jobs are connected to farming and agriculture and a change in the availability and quality of water will have a significant impact on the population. These nations have very limited resources and are unable to adapt to climate change compared to wealthier nations who can import water if required.

A rise in global temperatures means an increased risk of extreme and frequent floods during the rainy season and the possibility of longer droughts during the dry season. Even a slight temperature increase of one degree Celsius is predicted to have a significant impact on the water supply.

A rise of one degree Celsius would threaten water supplies for 50 million people as small glaciers disappear in the Andes. A rise of five degrees Celsius could result in the disappearance of large glaciers in the Himalayas which would affect one quarter of China’s population and millions of people in India.2

The effect of climate change is also having an impact on water supplies in developed nations including the United States. After a recent drought in California was declared over, a government report highlighted that the long term availability of water could be a problem. Annual water flow in three Californian river basins is expected to decline by as much as 8-14% over the next four decades as a result of climate change. The long term effects are expected to be increased flooding in winter due to early snowmelt and water shortages in summer. Local authorities are now urging for more water conservation and a sustainable approach to water management to help combat climate change, the increasing population in Southern California and their reliance on imported water.3

In Australia the average temperatures have increased by 0.9ºC since 1910 and because of the variable amount of annual rainfall the country is already facing challenges with managing its water resources. Climate change projections indicate reduced rainfall across certain areas and an increased risk of drought. Since the mid-twentieth century winter rainfall in south-west Western Australia has declined which has led to a severe drop in the annual inflow into reservoirs supplying Perth. Other cities in Australia are now facing the same problem and in addition to the effects of climate change they also have to cope with a rise in population.4

The UK has also been affected and floods across many areas in 2007 are believed to have been caused by climate change. Environmental organisations are working closely with authorities to ensure that areas prone to flooding are better prepared for extreme weather events in the future.5

Climate model simulations and other analysis suggest all natural sources of water could be significantly affected over the coming decades. Countries all over the world need to begin planning for these changes by implementing water conservation techniques and a sustainable system for water management to combat potential floods and extreme droughts.