The Climate Surprise

Benefits of atmospheric CO2
by Craig Idso
We on Earth benefit from the rise of
atmospheric CO. But we seldom
hear this important fact and its crical
implicaons. Studying the biological impacts
of rising atmospheric CO has occupied my
professional life for nearly three decades now.
Time and again, governments, nongovernmental
organizaons, internaonal agencies,
societal think tanks, and even respectable
scienfi c organizaons undertake to spend
mulple millions of dollars wring and promong
large reports about climate change.
Yet in nearly all of these endeavors they have
failed by not properly evaluang, or even
acknowledging, the manifold real and measurable
benefits of the ongoing rise in
the air’s CO content. As a result, the
posive impacts of atmospheric CO
enrichment remain largely ignored.
There are three main benefi ts of
atmospheric CO enrichment: more CO
increases plant producvity, enhances
plant water use efficiency, and helps plants
to withstand and beer endure various
environmental and resource limitaons
and stresses.
Regarding plant producvity, carbon
dioxide is the primary raw material ulized
by plants during the process of photosynthesis
to build and construct their
ssues. It is the “food” that sustains essenally
all plants on the face of the Earth.
And the more CO they “eat” or take in
from the air, the bigger and beer they grow, a
fact that has been conclusively demonstrated in
thousands of laboratory and field experiments.
Figure . illustrates this truly amazing
benefit. As the atmosphere’s CO concentra-
on increases to six mes above that of its
current value, this extra “food,” if you will, induces
a growth enhancement in most plants that
reaches upwards of percent.
In Figure . we see the growth-enhancing
effects of atmospheric CO enrichment on pea
plants. All plants in the figure were grown under
idencal condions except atmospheric
CO content. Grown under three different
atmospheric CO concentraons, the effects
Figure 2.1: Adding CO2 to the atmosphere enhances plant growth.
Source: adapted from Idso, K.E. 1992. Plant responses to rising
levels of atmospheric carbon dioxide: a compilaon and analysis of the
results of a decade of internaonal research into the direct biological
effects of atmospheric CO2 enrichment. Climatological Publicaons
Scienfic Paper No. 23, Office of Climatology, Arizona State University,
Tempe, Ariz.
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