https://www.earthmagazine.org/tags/cities/ Recent content in Cities on EARTH Magazine Hugo en-US American Geosciences Institute. All rights reserved. Mon, 08 Feb 2016 13:06:37 -0500 https://www.earthmagazine.org/article/urban-geology-emerging-discipline-increasingly-urbanized-world/ Mon, 08 Feb 2016 13:06:37 -0500 https://www.earthmagazine.org/article/urban-geology-emerging-discipline-increasingly-urbanized-world/ <figure class="earth-figure"> <img src="https://www.americangeosciences.org/static/earth/urban-geology-emerging-discipline-increasingly-urbanized-world/FranciscanmelangecroppingoutsouthofGoldenGate_CBentley.jpg" alt="At Marshall&#39;s Beach south of the Golden Gate Bridge in San Francisco, the Franciscan mélange is exposed. During last year&#39;s annual meeting of the American Geophysical Union in San Francisco, geologist Callan Bentley and others visited the site to photograph the rocks. Credit: Callan Bentley." loading="eager" decoding="async"> <figcaption>At Marshall&#39;s Beach south of the Golden Gate Bridge in San Francisco, the Franciscan mélange is exposed. During last year&#39;s annual meeting of the American Geophysical Union in San Francisco, geologist Callan Bentley and others visited the site to photograph the rocks. Credit: Callan Bentley.</figcaption> </figure> <p>The mass <a href="http://esa.un.org/unpd/wup/highlights/wup2014-highlights.pdf">urbanization</a> of the human race is a relatively new phenomenon in the history of civilization. In 1900, when geology was maturing as a science, only 10 percent of the global population lived in urban settings; now, this proportion has surpassed 50 percent, fed by both overall population growth and rural-to-urban migration. And by 2030, it is expected to reach 60 percent. The United States reached 50 percent urbanization around 1930 and is now approaching 70 percent. The urban population of Canada, meanwhile, accounts for about 80 percent of the country&rsquo;s people. Ten urban areas around the world now exceed 20 million people, with the Tokyo metropolitan area approaching 35 million — larger than the populations of most countries.</p>