course of years, the IPCC has produced several assessments of global warming
through teams of internationally respected scientists. Their 2007 conclusion leaves
little doubt that humans are impacting the atmosphere. Their continued work was
awarded the Nobel Prize for Peace.
What does the future hold? The IPCC has used a suite of numerical models to
assess global warming over various times and under various scenarios of rate of
greenhouse gas release. Using a plausible doubling of atmospheric carbon dioxide,
a middle solution from their suite of possibilities is that global temperature would
warm about 2°C in the coming century. This is three times the rate of warming
during the 20th century. The following are the qualitative likelihoods of future
conditions over most land areas as listed in the IPCC’s 2007Assessment:
- Warmer with fewer cold days—virtually certain
- Warmer with more frequent hot days and nights—virtually certain
- Increase of warm spells/heat waves—very likely
- Increased frequency or proportion of heavy precipitation falls—very likely
- Increased area affected by droughts—likely
- Increased frequency of intense tropical cyclones—likely
- Increased incidence of extreme high sea levels (tsunamis excluded)—likely
The projected geography of the warming is of great interest. Changes in temper-
ature would be due to the radiative forcing of increased greenhouse gases, but also
shifts in the global wind and pressure systems. To wit, the imbalance of energy
between equator and poles energizes large-scale wind systems. If warming
decreases the latitudinal imbalance, winds would blow less vigorously in each
hemisphere as a whole and displace wind and pressure systems out of their present
average positions.
A consistency among numerical climate simulations is the relatively lack of
warming ascribed to the tropics. This is not to imply that there would not be tropi-
cal effects. For instance, there are some small island countries in the Pacific and
Indian oceans that would virtually disappear if the IPCC’s middle estimate of
upward of a half meter of sea-level rise by 2099 verifies. Upper middle and polar
latitudes are projected to experience the highest temperature increases. The IPCC
list seems to indicate a plethora of harmful effects, but not all regions or countries
stand to be losers. Countries such as Russia and Canada may experience the open-
ing of new agricultural lands as permafrost thaws. Yet, a possible effect during
global warming is shifts in wind and precipitation patterns so that other lands
become untenable in terms of their traditional crops and practices. Some research-
ers have raised the specter of regional famines and, even, wars as a result.
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