Over the next two weeks, Next City will unroll short profiles of 77 people, places and ideas that have changed cities this year. Together, they make up our 2012 Disruption Index. Forefront subscribers can download the Index in full as a PDF, complete with beautiful designs and graphics by Danni Sinisi. Readers who make a $75 donation to Next City will have a full-color printed copy of the Index mailed to them.

In an increasingly metropolitan world, the issues of the city often bleed beyond city borders. From water security to transportation to clean energy infrastructure, the systems that keep metropolitan areas functioning are much bigger and more encompassing than any one municipality. To address many of these urban problems, people are realizing they’ll have to take a regional approach.

As an extreme example, Hurricane Sandy’s landfall on the Eastern Seaboard spurred the need for quick action across a wide geography. Volunteer and rescue groups from around the New York-New Jersey area and beyond converged on the hard-hit communities of Staten Island and the Jersey Shore to provide aid, which ranged from handing out bottles of bleach to helping people find missing loved ones. But not every regional issue is of such immediate emergency. On the slower, and arguably more devastating, side of the spectrum is the steady decline of the post-industrial cities of the Rust Belt. To try to tackle issues of economic decline facing cities across a large region, important investments have been made by groups like the American Assembly’s Legacy Cities Network to analyze the issues and propose solutions. For these types of multi-city and multi-state questions, it’s becoming more and more important to have a regional lens if there is any hope of finding answers.

Nate Berg is a writer and journalist covering cities, architecture and urban planning. Nate’s work has been published in a wide variety of publications, including the New York Times, NPR, Wired, Metropolis, Fast Company, Dwell, Architect, the Christian Science Monitor, LA Weekly and many others. He is a former staff writer at The Atlantic Cities and was previously an assistant editor at Planetizen.