Environmental Engineering Reference
In-Depth Information
9
Climate Change: What Have We Done?
The climate system is an angry beast, and we are poking it with sticks.
—Wallace Broecker, oceanographer and climate scientist, 2008
After what seemed like interminable wrangling over the reality of
climate change, the debate seems to have subsided. The evidence for
global warming, the most publicized sign of the change, is now so
overwhelming that even most of the hardened skeptics are onboard.
Arguments have raged for years about the adequacy and reliability
of numerical data and computer modeling, but biological evidence
cannot be refuted or doubted. The behavior of both plants and animals,
which cannot lie, cannot be deceptive, and is unaffected by emotion-
ally or politically based points of view, is totally convincing (table
9.1). Recognizing this, the hardiness zones determined by the Depart-
ment of Agriculture—regional maps by which gardeners evaluate what
can live in the ground through the winter—have been redrawn to
refl ect the northward march of plants into areas that were once
inhospitable.
The nonbiological signs of warming have always been persuasive to
most climate specialists but have been questioned by those who doubt
the reality of climate change (table 9.2). Many of those who do not
believe in climate change have this view because they confuse the issue
of whether it is getting warmer with the question of whether humans are
responsible. Polls reveal that Republicans, who typically are more protec-
tive of the fossil fuel industry, are more likely to doubt climate change
than are Democrats. As discussed later in this chapter, it certainly is
possible that astronomical factors are the main cause of the increase in
the carbon dioxide content of the troposphere and that human additions
have a relatively small effect.
