What is climate change?
Climate change refers to a change in the average temperature, precipitation, winds, and other aspects of the climate system. Weather, on the other hand, describes the constantly changing atmospheric circulation (including storms and the hurricanes) on a daily to weekly basis.
Paleoclimate evidence from ice cores, tree rings, and other natural recorders reveals that large, abrupt changes in the Earth's past climate such as in temperature and precipitation have occured. The changes have occurred over decades to centuries, sometimes affecting small regions, entire hemispheres, or the entire globe. The past abrupt changes are massive compared to anything we have experienced since humans have been keeping records of climate for the past 150 years. What if these abrupt climate changes were to occur in the future? Would ecosystems that we count on be affected? How would humans adapt? These questions and concerns motivate a vigorous ongoing research effort to understand the changes of the past and eventually to predict future abrupt climate change.
Chapter 1 is divided into three sections:
- (A) Historical Climate Change,
- (B) Comparing Ancient to Current Climates, and
- (C) Has the Earth's Climate Changed Over the Past 1,000 Years?
For a brief introduction on climate and global warming, watch these NASA Videos (Real Player is necessary to view):
After watching these videos, proceed to A. Historical Climate Change