As in the rest of the developed world, bike share programs now offer a clean, healthy transportation alternative in many major US cities.
Throughout most of human existence, population growth has been so slow as to be imperceptible within a single generation. Reaching a global population of 1 billion in 1804 required the entire time since modern humans appeared on the scene. To add the second billion, it took until 1927, just over a century. Thirty-three years later, in 1960, world population reached 3 billion. Then the pace sped up, as we added another billion every 13 years or so until we hit 7 billion in late 2011.
Even amid policy uncertainty in major wind power markets, wind developers still managed to set a new record for installations in 2012, with 44,000 megawatts of new wind capacity worldwide. With total capacity exceeding 280,000 megawatts, wind farms generate carbon-free electricity in more than 80 countries, 24 of which have at least 1,000 megawatts. At the European level of consumption, the world’s operating wind turbines could satisfy the residential electricity needs of 450 million people.