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process called evapotranspiration. This
process not only cools the trees but also
releases water into the air, cooling the sur-
roundings. Increased carbon dioxide causes
the leaves' pores to shrink and release less
water. Cao and Caldeira found that in some
regions, including North America and East
Asia, over a quarter of warming from in-
creased CO
2
in the atmosphere is a result
of decreased evaporative cooling by plants.
They also found that high carbon diox-
ide will result in greater runoff from the
land surface, as water from precipitation
increasingly bypasses the plant cooling
system and flows directly into rivers and
streams.
Thus the answer to the question of how
valuable increased CO
2
is to the kingdom
of plants is not a simple one. Yes, by some
measures plant growth is enhanced, but a
number of other, less desirable effects oc-
cur as well. Once again there is proof that
nature is never simple. But to look at CO
2
and plant interaction to the exclusion of
other impacts of global change such as sea
level rise is both absurd and irresponsible.
exaggerate climate change while ignoring
mistakes that underestimate it. A case in
point is sea level rise. The ipcc has been
consistently low in its estimates of sea level
rise rates in its last two reports. In 2001 it
incorrectly assumed that the Antarctic ice
sheet was not going to contribute melt wa-
ter to the rising sea level, a mistake that it
corrected in 2007.
Bjørn Lomborg, economist and adjunct
professor at Copenhagen Business School,
is among the most sophisticated of the
skeptics and in some circles is considered
a legitimate critic, but he is not. Lomborg
came on the scene in a big way with the
publication of his best-selling topic
The
Skeptical Environmentalist
(2001), and in
2007 he published
Cool It: The Skeptical Envi-
ronmentalist's Guide to Global Warming
. Both
topics deal with similar themes, mainly
that claims of catastrophe are overblown
and that cost-beneit analysis suggests the
need to pay more attention to other prob-
lems, such as poverty, AIDS, and malaria.
The most likely reason that the topics have
had such a large impact is that they have
the appearance, if not the substance, of a
legitimate, well-documented review of the
science of global change.
Lomborg's review of the science is in-
accurate, however, as documented in pain-
ful detail by Howard Friel in his topic
The
Lomborg Deception
(2010). Friel and others
point out that Lomborg's apparent reli-
ance on peer-reviewed scientific literature
is highly misleading. Often the literature
is misquoted or quoted out of context. It is
myths, misinterpretations, and
misunderstandings of the Deniers
myth
: The ipcc's mistakes tend to exagger-
ate or overblow the extent of climate change,
thereby demonstrating a systematic bias.
Far
from it; we believe that the ipcc tends to
be conservative, probably on purpose. The
deniers jump exclusively on mistakes that
