Climate & Weather

Sediment Trap Observations Aid Paleoceanographers
The geological record contains a wealth of information about Earth’s past environmental conditions. During its long geological history the planet has experienced changes in climate that are much larger than those recorded during human history; these environmental conditions range from periods when large ice sheets covered much of the northern hemisphere, as recently as 20,000 years ago, to past atmospheric concentrations of greenhouse gases that warmed Earth’s polar regions enough to melt all of the ice caps 50 million years ago. Since human civilization has developed during a fairly short period of unusually mild and stable climate, humans have yet to experience the full range of variability that the planet’s natural systems impose. Thus, the geological record has become an extremely important archive for understanding the range of natural variability in climate, the processes that cause climate change on decadal and longer time scales, and the background variability from which greenhouse warming must be detected