Microfossils tell history of methane release Research by UC Davis Professor Tessa Hill and graduate student Bart Critser focused on reconstructing past changes in natural methane seepage from the Norway Margin. This research indicates that during time periods of climatic warming, methane seepage may increase from gas hydrate reservoirs, acting as a “positive feedback” to the climate system. This research was supported by the American Chemical Society Petroleum Research Fund Very small fossils, such as this G. bulloides specimen, record the history of methane seepage in their shells via carbon isotopes