GEOG 131 Lecture Notes - Lecture 32: Foraminifera, Sea Surface Temperature, Silicon Dioxide
Document Summary
Proxy- ways to indirectly reconstruct temperatures, allowing us to infer: tree rings, bore holes, glaciers. Two types of proxies: human archives. Good for the last 100-500 years: natural archives. Long standing weather stations with annual temporal resolution: lake sediments. Lake sediments can tell us about past vegetation through pollen records. Human activity related to climate: pollen. Can learn how humans have affected the environment over thousands of years: ice cores. Longer period of time- 1000 to 10000s of years. Vostok ice core project in antarctica now has 80000 years of data: ocean sediments. 10000- 1 million years into the past. Microscopic ocean organisms can be used to analyze past climate. Foraminifera: temperature, morphology, calcium carbonate shells. Warmer water evaporates lighter isotopes > shells made of heavier isotopes. Feedback cycles: positive feedbacks > amplify change. Warming water releases co2: negative feedbacks > dampen change.
