For the Sept. 3rd How On Earth show we offer two features:

Wildfires Threaten Water Supplies: (start time 5:45) The wildfire burning in and around Yosemite National Park is now the fourth-largest in California’s history. Covering nearly 350 square miles, the Rim Fire is threatening the Hetch Hetchy Reservoir, which supplies residents in the San Francisco Bay Area with most of their water and power. It’s a lot like the 2012 High Park Fire—which sent ash and debris into the water supply of Fort Collins. These fires offer lessons on the risks wildfires pose to reservoirs. Dr. Bruce McGurk, a former water manager for Hetch Hetchy and a water consultant, speaks with How On Earth contributor Brian Calvert about the risks and future prospects.
Comet ISON Cometh: (start time 12:50) Comets have fascinated
humans for millenia. Aristotle argued comets were hot, dry exhalations gathered in the atmosphere and occasionally burst into flame. Some people thought that comets replenished Earth’s air. Still others believed they were a source of disease. Scientists today study comets because some are thought to be relatively pristine leftover debris from the formation of the solar system. And studying what comets are made of can provide us a glimpse back to the beginning of the solar system 4 billion years ago. Comet ISON, as scientists call it, is one that scientists predict will be relatively easy to view later this year. Dr. Carey Lisse, a senior research scientist at the Johns Hopkins Institute Applied Physics Laboratory in Maryland, speaks with co-host Joel Parker about comet ISON and its fascinating tails. For more information on ISON, go to NASA’s ISON toolkit, and this cool interactive model.
Hosts: Susan Moran, Joel Parker
Producer: Susan Moran
Additional contribution: Brian Calvert
Engineer: Jim Pullen
Executive Producer: Susan Moran
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Feature #1 – China’s Environmental Impact (start time 4:46): China’s meteoric economic rise is causing harmful side effects, ranging from choking air pollution domestically to threatened forests, wildlife and air quality around the globe. Of course China’s per capita greenhouse gas emissions still pale in comparison to those in the United States, and roughly one-third of China’s CO2 emissions are generated to manufacture goods that are exported to the U.S. and other nations. Craig Simons, a former journalist and author of a recently published book,
Feature #2 – 100 Year Starship (start time 15:35): Science and exploration tend to be long-term commitments. That’s well-known by fans of the “Hitchhiker’s Guide to The Galaxy” series, where the computer Deep Thought did calculations for 7.5 million years to find the answer to The Ultimate Question of Life, the Universe, and everything. However, projects on our world tend to be limited by shorter-term political and funding cycles. So it is hard enough to consider projects that require thinking a decade into the future, beyond many political lifetimes. What about projects that require thinking a century or more into the future, many generations from now? Well, that is exactly what one group of space exploration advocates is working toward. The project is called the








Feature #2: Zero Population (start time 15:58)

Colorado Clean-tech Industry (Start time 16:14): It’s not news that we are in an economic downturn. Nor is it news that the world is facing monumental environmental problems. How about a way to kill two birds with one stone? Co-host Tom McKinnon discusses how with Wayne Greenberg, director of the Fellows Institute, which is sponsored by the


