Australia's Murray Darling basin covers more than a million square kilometers, 14 percent of the country's landmass. It's the site of tens of thousands of wetlands, but increasing demand for water has stretched its resources to the limit.
Widely accepted numbers on how much of the world's population lives in cities are incorrect, with major implications for development aid and the provision of public services for billions of people, researchers say.
More than a billion people are at risk from a lack of air conditioning and refrigeration to keep them cool and to preserve food and medicines as global warming brings more high temperatures, a study showed on Monday.
As global temperatures rise due to climate change, the number of air conditioning units in use globally is expected to quadruple by mid-century, increasing from 3.6 billion today to 14 billion in 2050.
From the northern Himalayas to the sandy, palm-fringed beaches in the south, 600 million people - nearly half India's population - face acute water shortage, with close to 200,000 dying each year from polluted water.
Through the long summer months in India's capital, tens of thousands of people have cut back on daily showers and laundry because of a shortage of water that has led to fighting in some areas in which three people have been killed.