Three quarters of a billion people is a lot of people. And that’s how many people, within the next 22 years, will almost certainly run low on water – a necessity of life – in just the regions whose rivers are supplied with water from the glaciers in the Himalayas. To put that in perspective, 750 million people is more than twice the current population of United States. It’s about the population of all of Europe. In the year 1900 there were only 500 million people on the entire planet. Seven hundred fifty million people is a lot of people.