Introduction - The Global Climate System: Patterns, Processes, and Teleconnections - page 17

1.3.3 What are problem climates?
There are at least two ways to look at the term problem climates: from a
physical perspective and from an anthropogenic perspective. Climate pro-
cesses are physical in that they center on the physical characteristics of the
atmosphere. They are anthropocentric because climate processes intersect
with human activities and the resources on which those activities depend.
Physical perspective
The physical climate can be viewed as a problem if the scientific basis for
understanding it is highly uncertain. The climate is always changing on
time scales that range from months to centuries and beyond. Knowledge
about those changes is increasing through research and observations, as
tools for researching and monitoring improve. Climate anomalies that
might have surprised us decades ago no longer do, because we have now
witnessed their occurrence. A good example is the 1982-3 El Ni˜o that was
called the El Ni˜o of the century. The belief that such a label generated
was that societies were safe from the return of an event of such magnitude
for another hundred years. However, the 1997-8 El Ni ˜ o was so surprisingly
intense that scientists labeled it as the real El Ni˜o of the twentieth century.
Climate changes, in the form of the atmosphere warming by a few degrees
Celsius, generate a different set of ideas about what constitutes a problem
climate (IPCC 2001 ). In a way, climate changes (at present global warming)
force researchers and policy makers alike to enter into uncharted waters (i.e.
an increased level of scientific uncertainty), because there is no precedent in
recorded history for the current level of trace greenhouse gases in the
atmosphere, especially carbon dioxide. Scientists expect that with global
warming the nature of extreme climate and weather anomalies will change:
extremes are likely to change in location, intensity, timing, and duration. Even
in locations where people do not believe that they are living under a problem
climate regime, that regime could change, and not necessarily for the better.
Australian meteorologist Neville Nicholls (2003, personal communica-
tion) noted the following: ''The future climate is obviously the most impor-
tant 'problem' climate, since we can't be sure how it will change. So we need
to adapt as it is changing and that is proving to be very difficult. The recent
fires in eastern Australia (2002-3) show how a changing climate is a problem
climate. Last year's drought was much worse than previous droughts with
similar low rainfall because it was much hotter than previous droughts (with
consequently higher evaporation). This dried out the forests and made the
year set for the enormous fires that took place (and the fires were of an
immense size). We hadn't adapted our approach to fires to keep pace with the
changing climate that is causing more ferocious fires.''