Eric Walker added Culprit for Mass Extinction 445 Million Years Ago? Global Warming - The New York Times to a number of topics

Eric Walker added Ordovician - Wikipedia to Ordovician period

Eric Walker added The Anthropocene epoch: have we entered a new phase of planetary history? | Environment | The Guardian to a number of topics

Eric Walker added a number of topics and Paleozoic - Wikipedia to Paleozoic era, and added Paleozoic era to Phanerozoic

Eric Walker added Late Ordovician mass extinction (LOME) and Ordovician–Silurian extinction events - Wikipedia to Ordovician-Silurian extinction events, and added Ordovician-Silurian extinction events to Ordovician period, Silurian period and Extinction events

Eric Walker added Ordovician-Silurian extinction events and a number of links to Ordovician period, and added Ordovician period to Paleozoic era