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The extremely complex interrelations between
human activity and natural forces—air masses, winds, ocean
currents, evaporation, and precipitation—means that researchers
from many fields pool their efforts in an attempt to understand
how the climate is reacting to changes. But this complexity
also means that knowing what the climate will be like in fifty
or one hundred years is among the most challenging problems
in science.
Some of the changes researchers in all these areas are exploring
may seem small, especially in relation to the typical temperature
changes associated with daily and seasonal cycles. But although
regional and short-term temperatures do fluctuate over a wide
range, global temperatures are generally very stable. Indeed,
during the last Ice Age (about 20,000 years ago), the average
global temperature was only about 5°C cooler than it is
today.
The fact that seemingly small changes can have dramatic effects
is one reason why an understanding of the data, techniques,
and controversies of global climate research is so fundamental
to understanding the phenomenon itself. We’ve collected
and discussed some of the data on the following pages to give
you a sense of how the problem is being studied—and what
all that research may be telling us. |
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