 Choosing
the Right Climate Model:
Thomas Crowley Uses the Past to Predict the Future
A conversation with the Nicholas School's Scottee Cantrell
SC: What is involved in choosing
or creating a good computer model?
TC: What I do is take models that have been already
developed and apply them in certain scenarios and physical
interests (past climates).There is an art to choosing a model.
The idea is to identify an interesting scientific question
and ask whether you can formulate some sort of hypothesis
that can be addressed with the model. Different types of climate
questions require different types of models, so if you restrict
yourself to one type of model you narrow down the choice of
questions you can address.
SC: What is the most important
thing you've learned about models that people in the field
of environmental management need to know?
TC: I've always been interested in comparing how well
models simulate what is actually changed as a result of such
things as moving continents around or ice sheets. What I've
learned from that experience is that models have provided
great insight into how these processes have changed and as
a result have given me greater confidence in the overall ability
of models to simulate climate change correctly. One of the
big questions with respect to global warming is how much can
you believe in these models. My experience says, yes, there
are uncertainties, but overall they give us approximately
the right answer in terms of the magnitude of climate change
that is being predicted. My feeling is environmental managers
have to have more than a superficial understanding of models,
they need some sufficient understanding in how far you can
go in believing models. They don't have to become a modeler,
but they have to appreciate why modelers have some level of
creditability.
SC: What are some of the
things you are finding when you use models to peer into the
future?
TC: What I've predicted for the future is not different
from other researchers, it is just that I have put it in the
perspective of what we have learned about in the last 1,000
years. I know that we can expect a major climate change, a
very significant climate change both in magnitude and speed
that will take place as a result of global warming. It has
tremendous implications for policy. It doesn't necessarily
mean we have to stop it, but one would be foolish to think
that everything will work out for the best if we do enter
a world of major climate change.
SC: What areas are you focusing
on now?
TC: One of the big questions we have about the climate
of the future is "How big is the change going to be?"And that
question in scientific language is "How sensitive is the climate
system to a given level of greenhouse gas forcing?" We don't
know for a given level of forcing if we are going to get a
really big response or a moderate size response. One of the
things I've been doing is trying to see if we can constrain
the magnitude of that response by looking at the climate over
the past 1,000 years. That would be a nice contribution if
we can convince ourselves that we can say something with enough
statistical confidence.
SC: How do you see your role
in the Nicholas School? What does it mean to be one of the
Nicholas professors?
TC: I think that when someone is brought in as a
chaired professor there is some hope that they will provide
some leadership, or at least some advice and ideas about how
things might change, and what directions might be taken in
the school. I view my role as several fold. One is to help
establish a new professional program in global change in the
Nicholas School. Another is to do research into the area of
global change. I have talked to various members of the division
here to ask if there is anything we can do scientifically
in the area of global change that is unique, in which we can
make a real contribution. One way might involve the effect
of sea level rise on barrier islands and coastal features.
I've been impressed that Brad Murray (assistant professor
of coastal processes and geomorphology) has some approaches
to this problem that I think are kind of rare. So, we are
actually exploring-Brad is taking the lead-combining our predictions
for future climate change and what might happen to some of
these coastal features.
Scottee Cantrell is director of communications
for the Nicholas School |
