In the Arctic, enormous releases of methane, a potent greenhouse gas, threaten the climate. Colossal explosions shake a remote corner of the Siberian tundra, leaving behind massive craters. In Alaska, a huge lake erupts with bubbles of inflammable gas. Scientists are discovering that these mystifying phenomena add up to a ticking time bomb, as long-frozen permafrost melts and releases vast amounts of methane, a potent greenhouse gas. What are the implications of these dramatic developments in the Arctic? Scientists and local communities alike are struggling to grasp the scale of the methane threat and what it means for our climate future.


  • 00:00 Introduction
  • 02:22 Giant Sinkhole in Siberia
  • 05:54 Evidence of Methane in Craters
  • 09:02 Alaskan Lake Bubbling
  • 14:47 Effects of Permafrost Thaw on Climate
  • 17:26 Native Alaskan Solutions to Permafrost
  • 21:37 Organic Matter Impacted by Permafrost
  • 24:44 Greenhouse Gasses Emitted from Permafrost Thaw
  • 33:37 Fossil Methane in Earth’s Crust
  • 42:19 Tipping Point: Arctic Regions are Sinking
  • 47:47 How Communities are Finding Solutions
  • 50:15 Conclusion

This program was produced by GBH, which is solely responsible for its content. Some funders of NOVA also fund basic science research. Experts featured in this film may have received support from funders of this program. Funding for NOVA is provided by, the David H. Koch Fund for Science, the NOVA Science Trust, the Corporation for Public Broadcasting, and PBS viewers.


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