Methane bubbles form interesting shapes in the ice near Fairbanks, Alaska. Many newly-formed Arctic lakes have bacteria feeding on plant detritus previously frozen underground and producing methane as a waste product. Methane's contribution to the greenhouse effect is considerably more than that of carbon dioxide. Global warming extrapolations could be grossly underestimated if methane contributions from lakes have not been properly studied and are not taken into account. PHOTOGRAPH BY MARK THIESSEN.