Ihave great respect for Mike Walters and have enjoyed his many fine papers
for the CAS. However, I was very disappointed with what he wrote on climate
change in the recent issue of
Contingencies (“The Jury’s Still Out on Global
Warming,” July/August). I will limit my
comments to the most actuarial part of
his paper—his discussion of hurricanes.
Since hurricanes gain strength when
passing over warmer water, it’s plausible
that warmer summers would lead to a
larger percentage of more severe hurricanes. However, this doesn’t depend on
why the temperature is higher, whether
due to human activities, natural cycles or
a combination of the two. Also, weather is sufficiently complicated that it’s
unclear whether significantly warmer
summers on average would in fact result
in a larger expected percentage of severe
tropical storms over the whole earth, let
alone those in one basin (the Atlantic)
that hit one region (the United States).
In any case, the observed significant
increase in average temperatures didn’t
start in 1950 or 1960. Based on the graph
on Page 50, there was about a 0.5-degree
Celsius increase by 1990. Even if warmer
temperatures will on average produce
more severe hurricanes, it’s unclear
how much of an effect a 0.5-degree rise
would cause, as opposed to, for example,
a 2-degree rise.
The frequency of hurricanes hitting
the United States is subject to lots of
random fluctuations, as well as natural
cycles. The severity of these hurricanes
is even more random. If there has been
an increase in the expected severity of
hurricanes hitting the United States
since 1990, we don’t have enough data
to measure the effect. In actuarial terms,
there isn’t enough credible data to answer the narrow question of a possible
change in expected severity of these
More importantly, even if there were
enough data, the severity of hurricanes
wouldn’t address the important issues:
❯ Has the temperature increased?
❯ If so, why has it increased?
❯ What is likely to happen to the temperature in the future under different
❯ Has the climate changed?
❯ If so, why has it changed?
❯ What is likely to happen to the climate
in the future under different scenarios?
Just because Hurricane Katrina
changed the minds of many members
of the media and the public on climate
change doesn’t make it relevant to rational discussion. People like narratives. It
should be obvious to any actuary that a
single hurricane such as Katrina can’t
by itself prove or disprove global warming or anything else about long-term
One can “prove” anything with the
right narrative and by selecting one’s
Faith and Science
The juxtaposition of the opposing arti- cles on causes of global warming by Ms.
Woerner (“Managing the Risk of Climate
Change”) and Mr. Walters (“The Jury’s
Still Out on Global Warming”) in the July/
August Contingencies led me to analyze
the reasoning. I realized that Ms. Woerner’s arguments all implied we should have
faith in the “science” behind the politically correct viewpoint of the cause.
The increase in CO2 since the mid-
1700s is assumed to be due to burning
fossil fuel, but it is more likely to be the
extra CO2 recycled in a natural biomass
half again (or more) as lush as the biomass produced by the two Americas as
they transformed from a natural state to
agricultural use during the same time
The only carbon that is stored is
turned to coal or oil (a process not currently operative). Otherwise, CO2 is
turned into biomass that turns back
into CO2, H2O and dirt at rates varying
from hours to centuries. If the biomass
is reduced, the CO2 remains in the
You need only to observe the fields
you pass as you drive to work (especially
in the spring) and compare vegetation in
the field and fence row to see which is
producing the most biomass. Faith has no
business in a discussion of science. Biomass includes the herbivores, carnivores
and omnivores supported by the vegetation. Methane is an intermediate step in
the recycling back to CO2 and H2O and
may be stored as a hydrate, which can
have the fossil fuel signature.
John H. Beales Jr.
Stick to the Facts
I’ve always prided myself on being an actuary, considering that we reach
our conclusions based on fact and not
In the July/August version of
Contingencies, Michael Walters pens an
obviously biased article (“The Jury’s Still
Out on Global Warming”). The vast majority of respected scientists (well over