Geoscience Reference
In-Depth Information
waiting for conditions to change. In his
topic
The Climate Fix
(2010), Pielke con-
cludes that decarbonization (lowering CO
2
production) won't work, because as long as
global economies may be at stake, effective
inaction on CO
2
reduction by the world's
nations is almost a certainty. His solution:
alternative sources of energy.
industrialization, dam construction, and
deforestation may be responsible for some
changes. In the United Kingdom scientists
provided regional projections of climate
change using a grid made up of 25-km
2
(15.5
square-mile) squares. The report was sup-
posed to be released in 2008 but it was not,
because an independent review concluded
that the limitations, which were quite seri-
ous, were not made clear in the report.
The scientific community is also not exactly
sure what will happen as we continue to in-
crease greenhouse gases in the atmosphere.
The amount of future warming of the at-
mosphere per unit volume of released ghg
is uncertain, because there are unknowns
such as the proportions of different gases,
the role of cloud cover and aerosols, the
nature of future solar radiation, and the
role of poorly understood feedbacks. Are
there tipping points out there from which
we cannot recover? We have some general
understanding of these things, but our
knowledge is certainly not precise. And it
probably never will be precise, because na-
ture defies complete understanding. This
problem often frustrates policymakers, and
provides ammunition for skeptics who of-
ten throw out the baby of well-understood
phenomena with the bathwater of less-
well- understood phenomena.
A number of the Earth and atmospheric pro-
cesses that cause global temperature change
are not well understood.
These include the
roles of aerosols and cloud cover, the future
of ocean warming, and the various compo-
nents of the earth's carbon cycle. In addi-
tion, the scale of methane emissions that
can be expected from various sources and
the scale of CO
2
emanating as a result of
land use changes remain uncertain.
Extreme events, including storms, tropi-
cal hurricanes, intense precipitation (rain,
sleet, snow), extreme temperatures, and
droughts, are very important elements of
global climate change and are important
to forecast. But because these are uncom-
mon events, they are harder to forecast and
characterize than climatic averages.
Future changes in the ice sheets will have
a major impact on sea level rise and are
not easily predictable. The West Antarctic
ice sheet is a particular enigma. Its melt-
ing rate may depend on the survival of ice
shelves that hold back the outlet glaciers,
the release from grounding on continental
shelf islands as glaciers melt and become
The problem of how climate change will play
out and what causes it on a continental and
global scale is generally understood, but at a
local level climate change remains a major un-
certainty.
At a local level, events unrelated
to global climate change such as pollution,
