Dr. Richard B. Alley
Evan Pugh Professor of Geosciences and Associate of the EMS Environment Environment Institute, Pennsylvania State University
Abrupt Climate Change, Oceans, and Us
Are we "rocking the boat" when it comes to climate? Explorations of the Earth's history show that when the climate system has been forced across a threshold, it can abruptly shift to a new climate, much like a tipping canoe that suddenly capsizes. These shifts have occurred within a single human generation, taking as little as a decade to move from a cooler to warmer climate or vice versa. The ocean acts as a major driver of our planet's climate machinery, in part through its capacity to store and transport heat in major ocean currents such as the Gulf Stream. Past abrupt climate changes have disrupted ocean circulation, collapsed ice sheets, and produced major shifts in regional weather patterns (e.g. droughts, floods, severe storms) that have had widespread impacts on the environment and human communities. Because human activities affect the air, water, ice, and ecosystems that drive the earth's climate machinery, humans could increase the chance of an abrupt climate change in the foreseeable future.
