Define a climate feedback and sketch an example as a feedback loop. Does the CO2–weathering feedback work in a positive or negative direction? Explain. List the key lines of evidence for present...

Define a climate feedback and sketch an example as a feedback loop. Does the CO2–weathering feedback work in a positive or negative direction? Explain.

List the key lines of evidence for present global climate change, and summarize the scientific evidence for anthropogenic forcing of climate?