In 2010, the world reached a milestone: The number of people living in urban areas reached 50 percent. This monumental shift from rural to urban living comes with consequences. Growing urban populations will have to learn to efficiently deal with increased demands for energy, transportation, sanitation, food and water while balancing the environmental impacts of such densely populated regions.

Volcanism is often implicated in periods of abrupt cooling. After the 1991 eruption of Mount Pinatubo in the Philippines, for instance, global temperatures dropped by half a degree Celsius due to airborne particulate matter blocking solar radiation. However, these effects don't normally last more than a few years. Yet, a recent study blames volcanism for a 500-year cold period referred to as the Little Ice Age.

In celebration of the release of the revised 5th edition Glossary of Geology for the Kindle and Nook platforms, the American Geosciences Institute (AGI) has started a free GeoWord of the Day service.

AGI conducted a follow-up study to research conducted by Houlton (Geoscience Currents 45-48) in a Geoscience Currents series that examines the various pathways taken by undergraduate geoscience majors when deciding to concentrate in the Earth sciences.

The revised 5th edition of the Glossary of Geology, published by the American Geosciences Institute, is now available as an e-book for the Kindle and the Nook. The e-book version provides users with the full layout and text of the Glossary for half the price and none of the pounds of the print edition.

The North Star, the Pole Star, the Guiding Star, Polaris: Its many names reflect the many centuries humans have gazed northward to it for guidance. However, recent studies have shown that the North Star is losing mass at a significant rate. Will Polaris, steadfast beacon for early sailors and adventurers alike, vanish from the night sky?

Enrollments and degrees in the geosciences in the United States dipped during the 2010-2011 academic year as detailed in the latest Geoscience Currents published by the American Geosciences Institute. After peaking the year before, enrollments slipped back to 2008-2009 levels with undergraduate geoscience enrollments dropping about 8 percent and graduate enrollments falling approximately 3 percent. Degrees similarly declined, with Bachelor's degrees dropping 9 percent, Master's dropping 6 percent, and Doctorates dropping 4 percent.

A new generation of lidar, or Light Detection and Ranging technology, is bringing the laser-based survey method down to Earth. The new technology involves mounting instruments atop cars, boats and even backpacks. These new mobile mapping systems will give geoscientists a whole new way to map and study the world.

The debate over hydraulic fracturing has recently focused on the rise in seismicity throughout the primarily stable interior of the United States. These intraplate regions, though not unfamiliar with earthquakes, have been experiencing an increased amount of seismic activity in the last decade. This unusual increase is likely to be caused in part by wastewater disposal practices related to natural gas production. With such a sensitive issue it is important to keep the facts in perspective.

The idea that the Arctic is changing is not breaking news. Sea-ice extent has been declining by 12 percent per decade since 1979, and the ice is thinning too. Because of this, new shipping routes are becoming accessible during the summer months, and the Arctic is beginning to attract parties interested in resource exploration, scientific research and tourism. Therefore, a more accessible Arctic not only means environmental changes, but also changes in our economy and our national security.