Introduction - The Global Climate System: Patterns, Processes, and Teleconnections - page 20

In the mid 1970s atmospheric chemists (Rowland and Molina 1974 ) discovered that
chlorofluorocarbons (CFCs), while inert in the lower atmosphere, break down in the
stratosphere in the presence of ultraviolet radiation thereby freeing chlorine atoms
that combine and recombine with oxygen by breaking down ozone molecules (see
Section 5.7 ). As a result there is a thinning of the ozone layer that protects the
Earth's surface from lethal amounts of UV radiation. Once emitted, these chemicals
have a lifetime in the atmosphere on the order of many decades. There is still an
illegal trade in CFCs.
The demise of the Aral Sea serves as a good example of environmental degradation
that resulted from political decisions. After 1960, the Soviet government expanded
cotton cultivation from about 3.5 million ha to 7 or more million ha in its Central
Asian Republics. A sharp increase in diversions for irrigation from the region's two
major rivers has reduced the surface area of the sea by more than half, and its
volume by more than a third. The sea has broken into two parts, and salinity and
pollution have made its water unfit for most living things. The sea continues toward
total desiccation as a result of policy makers paying little regard to the fragility of
the natural environment. In addition winters have apparently become colder and the
summers hotter.
Many countries continue to base their economic growth plans on the continued, if
not expanded, use of fossil fuels (coal, oil, and natural gas) that are known to
produce heat-trapping carbon dioxide emissions. Much debate has taken place on
how and when to reduce such greenhouse gases (GHGs) emissions (i.e. Kyoto
Protocol), but the increases in emissions continue.
The long-term changes of concern to policy makers as well as scientific
researchers have been in temperature, precipitation, winds, relative humidity,
and seasonality. Sea level rise and glacial melt are other major climate change
indicators of paramount concern, especially to those living in coastal low-
lying areas. Today, the debate is whether human-induced changes to physical
forcing factors, which influence the behavior on various time scales of
elements of the global climate system, can bring about ''deep'' climate
changes that before humans could only occur naturally.
Societies have difficulty in coping effectively with today's climate anoma-
lies and their impacts on societies and environments. Reasons include but are
not limited to the following: scientific uncertainty, a blind faith in the devel-
opment of new mitigating technology, scientific uncertainty about climate
phenomena and about their impacts, the 2-4-6 years political cycle in the
USA (the attention span of politicians in various issues relates to their length
of term in office), and the mysterious reasons why known ways to cope with
anomalies are not used.
With the advent of satellite imagery in the 1960s we have been able to see
from space the extent to which human activities on different sides of domestic