We are
extremely grateful for the insights and suggestions made
by the reviewers who took the time and opportunity to look
over the regional summary when it was a work in progress.
Below is a summary of the comments taken from these reviews.
In many instances, several reviewers made different versions
of the same comment s. These comments and the responses
to them are listed under general comments. The names of
the most of the reviewers are listed after the questions.
|
|
General
Comments
Other
studies have examined the potential impacts of climate change
on the Great Lakes region. What makes this report so different?
|
| The
climate scenarios that were used in this study came from GCMs
that included the effects of aerosols and which accounted for
more realistic increases in CO2. Previous studies used older
GCMs that did not account for aerosols and assumed an instantaneous
doubling of CO2 levels |
|
I
have seen from other sources and references that the GCMs
used in this report do not simulate very well some of the
temperature and precipitation aspects for the current climate
— particularly across Canada (just north of the Great
Lakes region). How then can the results be credible for a
time period 100 years into the future?
|
| Almost
all GCMs exhibit biases. A bias is an error (e.g., in temperature
or precipitation) that appears over a given region — independent
of how external forcing mechanisms are changing (e.g., increases
in CO2). Many of the results in this report are obtained with
respect to these biases. That is the bias is somehow considered.
For example, to compute changes in lake levels by the year 2100,
the change in model precipitation and temperature between the
present and future time periods are added to the actual observed
climate for the present. This future climate scenario is the
one that is used to evaluate impacts on lake levels — thus
accounting for model bias. |
|
Why
does this report focus on coping mechanisms rather than mitigation
strategies?
|
| This
report and the study from which it was derived were spawned
by a genuine scientific interest in understanding the impacts
of climate change. We felt as a team that including a discussion
of coping mechanisms was a responsible addition to the report,
because these mechanisms suggest possible and appropriate actions
regardless of whether climate is changing in the long term from
increasing greenhouse gases or in the short term from natural
interannual or interdecadal variations. We chose not to focus
on mitigation strategies because including such strategies may
suggest to some that we have some sort of political agenda in
reducing CO2 emissions. As representatives of the scientific
community, we felt that it would be outside our scope of scientific
responsibility to recommend any political actions. |
|
There
is not a lot of information on stresses in each of the chapters.
|
| The
real focus of the report is on describing the potential impacts
of climate change on the different sectors as were determined
by our regional stakeholders. More information regarding the
stresses on the sectors is provided in our Workshop Report. |
|
There
is not a lot of information on previous assessments in each
of the chapters.
|
| This
assessment addressed stakeholder concerns more so than aspects
that have been examined in previous efforts. Some of these concerns
have never been addressed before — like the impact of climate
change on respiratory illness in the Great Lakes region. Thus,
there were not too many previous studies that were very relevant
from a reference standpoint. Basic information regarding the
methodology is for the most part referenced. For example, information
about the agricultural models used (e.g., DAFOSIM) is available
in the referenced literature. |
|
There
is not a lot of information on coping mechanisms in each of
the chapters.
|
| The
real focus of the report is on describing the potential impacts
of climate change on the different sectors as were determined
by our regional stakeholders. More information regarding the
coping mechanisms for the different sectors is provided in our
Workshop Report. |
|
The
assessments do not have very detailed information.
|
| We
wanted to keep the report at a technical level where most of
our stakeholders, including high school students interested
in climate change, could understand most if not all sections
of the report. In effect, we tried to write the report at the
same technical level that one would find in a NOVA or National
Geographic Presentation. A series of articles will be published
in a special issue of Journal of Great Lakes Research in Spring
2001 that will contain much more technical information. |
|
There
is not much information on the assessment models used.
|
| The
emphasis on this report is on the results obtained from the
various assessment models and techniques — primarily to
keep the overall length of the report short. In all instances,
the models and techniques are referenced so the interested reader
can obtain more detailed information if so desired. |
|
Why
are all the results in English units?
|
| Even
though much of the world has already converted to SI units,
many Americans still feel very uncomfortable and have trouble
converting SI units to English units. Additionally, because
all of the other regional assessment reports also were and are
being written in English units, the results in our report are
much easier to compare. |
|
I
read the Upper Great Lakes Regional Workshop Report. How come
the sectors chosen for assessment don´t match the ones
that stakeholders identified at your workshop?
|
| The
choices for the sectors that were studied in our assessment
were based on a variety of factors including suggestions made
by stakeholders who attended our workshop, availability of interested
and trained researchers, availability of funds, and the existence
of appropriate models or techniques to conduct the assessment.
Thus, not all suggestions made by stakeholders could be addressed
in this effort. |
|
Why
aren´t the economic impacts described throughout the
report more quantitative?
|
| A
quantitative evaluation of the economic impacts given the short
time, existing resources, and latest socio-economic projections
was really beyond the scope of our effort. Thus, qualitative
information was provided instead. Even a qualitative approach
was beyond our scope in certain instances because of insufficient
resources and knowledge. |
|
Can
I use text and graphics from this report for educational purposes?
|
| Yes.
We encourage all people interested in our report and especially
teachers and others involved in education to use any text or
graphics for educational purposes. The information may not be
used in any way for profit without first obtaining written consent
from the University of Michigan. |
Chapter
1
What
exactly is the overlay approach and why did many investigators
use it for their analyses?
|
| The
overlay approach means that existing techniques and/or models,
which have been used for previous assessments with different
model output from older general circulation models (GCMs), were
used with the latest model output from the most recent GCMs.
This overlay of existing methodology onto new climate information
implies that the new assessment information can be either interpolated
or extrapolated from existing information. |
Chapter 2
This
chapter does not describe in sufficient detail the long term
historical changes in climate for the region.
|
| The
purpose of our report was not to place the concept of global
warming within the context historical changes or natural variations
of climate in the Great Lakes region. Rather, our mission was
to report how changes in temperature and precipitation patterns
related to global warming would affect water levels, agriculture,
etc . in the region. Thus, historical climate changes in the
region were not explained in great detail. |
Chapter
3
Why
are the GCMs that were used not US models?
|
| Because
of the time-critical nature of this effort, both regionally
and nationally, output from tested GCMs that was already available
was used rather than waiting even several more months for output
from a US model to become available. Output from the NCAR Community
Climate Model (CCM3) has since become available and from a temperature
and precipitation standpoint is consistent with output from
the models we did use. |
| Why
does the output for the two different GCMs that were used differ
so much? |
| Because
of the time-critical nature of this effort, both regionally
and nationally, output from tested GCMs that was already available
was used rather than waiting even several more months for output
from a US model to become available. Output from the NCAR Community
Climate Model (CCM3) has since become available and from a temperature
and precipitation standpoint is consistent with output from
the models that we did use.
|
| How
were the economic scenarios really used in your assessment? |
| The
qualitative evaluation of some of the economic effects of climate
change is based on the business as usual socio-economic scenarios.
Not included in the report are qualitative economic evaluations
based on good or bad economic scenarios. However, while readers
may assume that economic impacts for these other two scenarios
could be different — it is difficult to say whether the
effects will be less or more severe for a given sector when
considering a particular socio-economic scenario. |
| Most
GCMs do not include the Great Lakes and the water surface temperatures
projected by GCMs that do have the Great Lakes could be questioned
unless a lake model is attached that represents the mixing and
overturning of the lake water. |
| Lake
temperatures were obtained using an independent (off-line) lake
model that was forced by GCM output. It is true that a crucial
parameter of lake-effect snowstorms is the lake-air temperature
difference. However, because this study focused on intense storms,
where lake-air temperature differences are presumably large,
a small error introduced by incorrectly modeled lake surface
temperatures should not greatly affect results. Additionally,
the lake temperatures are not likely to be known more accurately
than the air temperatures. |
| Do
“lake-effect rain events” actually occur as such,
or would increased temperatures decrease vertical temperature
gradients and reduce the likelihood of precipitation? |
| The
concept of lake-effect rain may be less familiar to much of
the general public, although the physical processes are similar
to those for lake-effect snow. Changes in stability were accounted
for somewhat, again to the degree that GCMs can accurately simulate
850 mb temperatures. In the lowest 150 mb of the atmosphere,
the temperature changes from global warming will likely be constant
so that boundary layer stability will not change appreciably,
so that lake-effect rains will likely be as if not more intense,
especially when accounting for the increase in saturation vapor
pressure with temperature. |
Chapter
4
The
Canadian Model used in your assessment shows that lake levels
will not decrease as much as some of the earlier models suggested,
and the Hadley Model used in your assessment suggests that
lake levels will stay the same or increase. Don´t these
results confuse the reader and suggest that the models have
problems?
|
| Close
inspection of lake level projections from all of the previous
studies (which were included for comparison) as well as from
our study are actually very similar — with the common thread
being that none of the studies show significant increases in
lake levels. In that sense these results are not conflicting
and should not confuse the reader. |
Chapter
5
The
results in this chapter were obtained for Lake Michigan. Is
there any way to apply them to the other Great Lakes?
|
| The
model used to obtain the results for Lake Michigan was tuned
with parameter values specific for Lake Michigan. While the
quantitative results are not likely valid for the other lakes
without retuning the model, qualitatively the results suggest
that stratification will increase for all of the Great Lakes. |
Chapter
6
Why
does this chapter describe the impacts on land cover from
climate change scenarios from old GCMs?
|
| The
results regarding climate change impacts on potential vegetation
from the latest climate change scenarios was not available at
the time the report was being prepared. |
| Was
the fitting and optimization of the STASH model based on Great
Lakes region parameters only, or on full (North American) range?
Would this make a difference? |
| The
STASH model was tuned with parameter values valid for the Great
Lakes region. |
Chapter
7
How
valid are the results in this chapter for future corn, alfalfa,
and soybean productivity yields given the uncertainties of
interannual climate variability, pest infestations, and new
pesticide, fertilization, and irrigation technologies?
|
| Almost
no evaluation of climate change impacts can account for all
possible changes. Evaluating climate change impacts is still
in its infancy, and while such complications from pests can
be included hypothetically (e.g., increased pest scenario),
the results become even more difficult to interpret. The best
way to interpret these results is to consider that these productivity
changes are expected if it can be assumed that many other features
of the current agricultural system remain unchanged, which may
or may not be likely. |
Chapter
8
Why
is there more emphasis in the report on the climate change
impacts on respiratory illness than on heat-related morbidity
and mortality?
|
This
portion of the report was generated because of the recent increases
in reported asthma cases in the Great Lakes region (and elsewhere)
and because it has not been addressed much if at all in other
studies.
|
|
REVIEWERS
|
| D.
Briane Adams, US Geological Survey |
|
Dr.
Susan Levine, University of Vermont |
| John
D. Aber, University of New Hampshire |
|
Michael
MacCracken, Director, USGCRP National Assessment Coordination
Office |
| Donn
K. Branstrator, University Minnesota-Duluth |
|
Dr.
David Mladenoff, University of Wisconsin |
| Wally
Brinkman, University of Wisconsin |
|
Russ
Moll, Michigan Sea Grant Program |
| Michael
F. Burger, Ph.D. National Audubon Society of New York
State |
|
Michael
R. Moore, University of Michigan |
| Dr.
Russ Butler, University of Michigan |
|
Michael
A. McGeehin, PhD Centers for Disease Control and Prevention |
| Charlotte
Caldwell, Indigenous Environmental Network |
|
Thomas
Nizol, National Weather Service - Buffalo Ofc. |
| Lynne
M. Carter, USGCRP National Assessment Coordination Office |
|
Fred
Nurnberger, Michigan State University |
| Andrew
Comrie, University of Arizona |
|
Michael
Palecki, Illinois State Water Survey |
| Julie
A. Craves, University of Michigan-Dearborn |
|
Dr.
Jean P. Palutikof, Climatic Research Unit |
| Dr.
Thomas Crow, University of Michigan |
|
Brian
Potter, North Central Research Station |
| Dr.
Stewart J. Cohen, Sustainable Development Research Institute |
|
Dr.
Ronald L. Ritschard, University of Alabama in Huntsville |
| Dr.
Yosef Cohen, Fisheries & Wildlife |
|
Robert
Rohli, Louisiana State University |
| Dr.
Everett J. Fee, University of Calagary |
|
Thomas
Schmidlin, Kent State University |
| Dr.
Otto Doering, Purdue University |
|
Professor
Richard H. Skaggs Department of Geography |
| Michael
A. Donahue, Great Lakes Commission |
|
Eugene
Stakhiv, Phd US Army Corps of Engineers |
| Dr.
Kirsty Duncan, University of Windsor |
|
Alan
Solomon, EPA at Corvallis |
| Betsy
Foxman, University of Michigan |
|
George
Seielstad, Centers for Disease Control and Prevention |
| Gerry
Galloway, International Joint Commission |
|
Dr.
Lisa G. Sorenson, Boston University |
| Dr.
Robert H.Gray, University of Michigan |
|
Dr.
Eugene Takle, Iowa State University |
| Dr.
Peter H. Gleick, Pacific Institute for Studies in Development |
|
Stephen
Thorp, Great Lakes Commission |
| Benjamin
F. Hobbs, The Johns Hopkins University |
|
Kerry
Woods, Bennington College |
| Thomas
C. Johnson Large Lakes Observatory |
|
|
|
