Part one of term paper
The importance of human influence on global climate change was again highlighted in a groundbreaking study of Earth's temperature over the past 600 years. Reconstructing the global temperature record, climatologists have determinined that three recent years were the warmest years since AD 1400 -- 1997, 1995, and 1990. The study, conducted by ...

Part two of term paper
... temperatures in the northern hemisphere to within a fraction of a degree, going back to AD 1400. The study places in a new context long-standing controversy over the relative roles of human and natural changes in the climate of past centuries, according to Mann. Scientists were particularly interested in natural "forcings" -- factors that can affect the climate significantly but which are not part of the climate system itself. Based on statistical comparisons of reconstructed northern hemisphere t ...