Page 25 - Earth's Climate Past and Future

PART I

Framework of Climate

Science

limate change is a topic that naturally piques Today Earth’s climate is rapidly warming, and it is
our curiosity. In the recent past, the hot, dry clear that humans are a major cause of this change. As
Cinterval that produced the Dust Bowl of the scientists work to figure out how large the warming will

1930s drove thousands of farmers from the Great Plains be, part of the answer has come and will come from
west to California. A century earlier, air temperatures understanding the changes that occurred in the past.
were cooler than now, and valley glaciers occupied The chapters in Part I provide a general framework for
positions well down the sides of mountains, compared understanding climate change by addressing several
with their locations today. Considerably further back in questions:
time, 21,000 years ago, climate was so cold that
enormous ice sheets covered Canada and northern
Europe, and sea level was some 120 meters (~400 feet)
• What are the components of Earth’s climate system?
lower than it is today because of the amount of water
• How does climate change differ from day-to-day
stored as ice on land. Much further back, 100 million
weather?
years ago, warmer conditions had eliminated ice from
• What factors drive changes in Earth’s climate?
the face of the Earth, even at the South Pole.
• How do the many parts of Earth’s climate system react
These changes in the past occurred for natural
to these driving forces and interact?
reasons, some of them well understood and others still
• How do scientists study past climates and project
in the process of being unraveled. Climate science is a
changes that lie in our future?
young science, and many exciting discoveries lie ahead.