Water supplies and global warming. Water supplies are already limiting many human societies. Shortages are likely to become increasingly frequent as global warming interacts with growing populations and increasingly developed societies that demand more water for agriculture, manufacturing, and personal use. Water pollution is also a major problem. More than five million people die from waterborne diseases each year - 10 times the number killed in wars around the globe. Global warming is likely to increase these problems by increasing the frequency of both floods and droughts and changing the seasonal pattern of runoff from snowpacks and glaciers. In addition, salt water incursion into low lying coastal areas and river deltas will restrict agriculture, reduce availability of fresh water, and endanger fresh water wildlife.

Model precip deficet 2080-2099 compared to 1980-1999

The amount of water on Earth is fixed. Less than 0.01% of the planet's 1.4 billion cubic kilometers is easily accessible freshwater in lakes and rivers. About a fifth of the water used worldwide comes from the 30% of the world's freshwater which is stored in groundwater.

Soaring demand The world's population has tripled in the last 100 years, but water use has increased sixfold. Agriculture now consumes 70 % of the water used worldwide. Much more will be needed if we are to feed the world's growing population - predicted to rise from 6.8 billion today to 8.9 billion by 2050.

Water use is very uneven Water use is very uneven. Just like energy, Americans are by far the largest consumers. Water consumption will soar further as more people expect Western-style lifestyles and diets - one kilogram of grain-fed beef needs at least 15 cubic meters of water, while a kilo of cereals needs less than three cubic meters.

An estimated third of the world's population currently lives in water-stressed countries. This will likely increase to two-thirds within 25 years. Africa and Asia are already hard-hit by water stress. Increasing populations will create more pressure in the coming decades.

Global warming is also changing the distribution of diseases, particularly tropical diseases.

Malaria Malaria is a mosquito borne illness normally limited by temperatures. Rising temperatures have expanded its range and global warming could put as much as 65 percent of the world’s population at risk of infection by malaria. Last 6 months 14 cases in the US

The Asian Tiger Mosquito, Aedes albopictus, is an invasive species that has spread from its native range in Asia to all the other continents (except Antarctica). It is an aggressive daytime flier that bites rapidly, thereby avoiding most attempts to swat it. It can spread several diseases, including dengue fever and malaria.

Because it can be transmitted by the common household mosquito, Culex pipiens, West Nile virus spread rapidly after it was introduced at La Guardia airport in New York.