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New York Times Jan 22, 2004;_ 
ProQuest Historical Newspapers: The New York Tlmes (1851?2007) w1th Index (1851?1993)
pg. A27

 

Weather and climate

In the debate over climate change. there is an
understandable tendency to use recent
weather events to draw conclusions about
global warming. However. weather and climate
are not the same climate is far more com?
plex. .
While we all know what weather is. most
of us are less clear about climate. A region's cli-
mate is de?ned as the prevailing behavior of its
weather. including variability.
Several decades of weather
must ordinarily be con?
sidered to establish the
average conditions and vari-
ability of climate.

Thus. the recent re-
cord cold weather in the
Northeast US. does not indicate a cooling cli-
mate. just as last year?s record summer heat in
Europe does not confirm a warming world.

Geological evidence indicates that
Earth?s climate has varied continu0usly, warm-
ing and cooling due to changes on and beyond
Earth. Factors as diverse as variations in Sun-
light and Earth?s magnetic field. asteroid im-
pacts. Sun-Moon-Earth orbital interactions.
cosmic ray ?uxes. continentai drift. fluctuations
in sea level. volcanic eruptions. changes in the
biosphere. and massive ebbs and flovys of con-
tinental glaciers. have significantly influenced
climate. 

Changes in one feature can affect others.
During recent ice ages. another factor. green-
house gas concentrations. changed for rea-
sons that remain unclear. Evidence suggests
that shifts in the flow of dust and nutrients from
lands to oceans may have signi?cantly altered
the exchange of carbon dioxide between

 

 

Changes in one
feature can affect
others the

the air and oceans.

Observations and theory both indicate
that weather and important aspects of climate.
for instance El Ni?o events. behave in a chaotic
fashion that may never allow for definitive. long-
term predictions. These and other ?uctuations

. produce signi?cant natural climate variability.

For example. over the past thousand years his-
torical accounts and scientific data show evi-
dence of a Medieval Warm
Period followed by a Little
Ice Age.

In the face of natural
variability and complexity.
consecuences of
change in any single factor,
for example greenhouse
gases. cannot readily be isolated and predic-
tion becomes difficult. Geological and historical
records make clear the need to account for
natural climate variability and the integrated re-
sponse of the entire climate system.

ever the last few decades climate re-
search has made great progress. In particular.
research has highlighted the risks to society
and ecosystems resulting from the buildup of
greenhouse gases. At the same time. scientific
uncertainties continue to limit our ability to
make objective. quantitative determinations re?
garding the human role in recent climate
change or the degree and consequences of fu-
ture change.

This reinforces the view that. as countries
and societies work to find acceptable ap-
proaches to address climate change while con-
tinuing to promote global prosperity. there is an
ongoing need to support scienti?c research to
inform decisions and guide policies.

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