date: Mon, 15 May 2000 13:15:58 -0600 (MDT)
from: Dallas McDonald <dallas@cobra.ATMOS.ColoState.EDU>
subject: review
to: M.Hulme@uea.ac.uk


Attached below are two emails that were sent to Dr. Michael
C. MacCracken of the National Assessment Coordination Office at the
U.S. Global Change Research Program (1) reviewing the Summary for
Policymakers of the IPCC Working Group I's Third Assessment Report,
and (2) a review of Chapter 10 entitled "Regional Climate Simulation --
Evaluation and Projections" from the same report.  I would appreciate
any feedback on issues that I have overlooked or overemphasized.

With Best Regards,

Roger A. Pielke, Sr.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


>From dallas@cobra.ATMOS.ColoState.EDU Wed May 10 21:16:15 2000
Date: Mon, 8 May 2000 14:13:02 -0600 (MDT)
From: Dallas McDonald <dallas@cobra.ATMOS.ColoState.EDU>
To: Mike MacCracken <mmaccrac@usgcrp.gov>

Subject: REVIEW of SPM

Dear Mike,

I appreciate the opportunity to review the Summary for Policymakers
(SPM) of the IPCC Working Group I's Third Assessment Report. As we
have discussed in the past, I have very substantial concerns regarding
the focus of the Report and its incomplete coverage of climate
processes. I provided similar comments to the 1992 IPCC Supplement and
the 1995 IPCC Report which were not addressed in the final report. The issues 
that I raise are important scientific points that, if addressed by the IPCC, 
would contribute to its authoritative role. 

My specific concerns with the SPM can be summarized as follows.

*Landscape processes directly and indirectly significantly influence
 the Earth's climate system through biophysical, biogeochemical, and
 biogeographical effects.

*Human-caused landuse change has an effect on local, regional, and
 global climate that is as significant as projected by the IPCC due to the
 radiative effect of anthropogenic inputs of greenhouse
 gases.

*Since landscape processes (and other atmosphere-surface interactions)
 involve complex nonlinear feedbacks, the prediction of future climate
 involves much more than the radiative effect of human-caused
 increases of greenhouse gases.

*The assessment of temperature trends using land-surface data, except
 for urbanization, has not considered how local and regional landuse
 change has altered the local and regional climate.

The importance of landscape processes in the global climate system has
been recently summarized in Pitman et al. (1999 and references
therein). The importance of landscape processes in carbon
sequestration and release is recognized in the SPM (e.g., line 50,
page 5), which makes the exclusion of the influence of vegetation and
soil dynamics on the Earth's energy and water budget all the more
surprising. Wang and Eltahir (2000a,b), for example, discuss the
critical role of biosphere-atmosphere interactions in the Sahel
region of Africa, and the need to include biospheric processes as
dynamic components of climate models.

As carbon dioxide concentrations continue to increase, this enrichment
will provide a more favorable environment for plant growth with, as of
yet, unknown consequences on the Earth's climate system.  Our initial
work in the central grasslands of the United States using a coupled
atmospheric-biogeochemical model (Eastman 1999; Eastman et al. 2000)
indicates that the effect of doubled carbon dioxide would be improved
water use efficiency and greater vegetation growth. The net effect, on
time periods as short as a growing season according to the coupled
models, would be a cooler daytime environment and a warmer nighttime.

The role of human-caused landscape disturbance and change on the
regional and global climate other than as a component in the carbon
budget, is ignored in the SPM. Human-caused landscape change includes
deforestation, overgrazing, agricultural activities, and
reforestation.  Leemans (1999), for example, shows that most landuse
change occurred in the 1900s and that landuse change is
accelerating (see Figure 1 of his paper).  O'Brien (2000) provides
additional information on the accelerating rate of  tropical
deforestation.  Pitman and Zhao (2000) and Chase et al. (1996, 2000a)
have presented results that indicate a substantial effect on the
Earth's atmospheric circulation thousands of kilometers from where
historical landscape changes occurred.  These teleconnections in the
model, for example, produce major shifts in the polar jet stream, with
substantial higher latitude regions of warming and cooling.

The importance of these two additional human perturbations to the
climate system (landscape change, and the biological effect of
increased carbon dioxide concentrations) complicate the prediction of
the future climate. Climate change is not as simple as stated in the
SPM (line 43, page 2 and following) which indicates that the radiative
effect of increased greenhouse gases and aerosols dominate how the
climate changes. The effect of pollution aerosols on cloud
condensation nuclei and ice nuclei in clouds complicate prediction
skill even further (Pielke 1984). In their paper discussing the effect
of human activity on radiative forcing of climate change, Shine and
Forster (1999) specifically state that "...climate change can occur
due to non-radiative processes, such as land use changes ...; such
changes are not considered here."  Trenberth (1999) states that
"Improving predictions of what the climate will be, not just with
idealized scenarios but taking all factors (including solar radiation,
land use change, aerosol effects, and biogeochemical feedbacks) into
account is a high priority."

The consequences of these additional human perturbations of the
climate system, and the variety of feedbacks across a wide spectrum of
time and space scales, will reinforce the conclusion of a "discernible human 
influence", but also limit our ability to predict the future
climate.  Pielke (2000) illustrates that the IPCC GCM simulations are
more appropriately defined as sensitivity experiments (where only a
subset of human perturbations) are performed. They should, therefore, be
communicated to policymakers as a subset of possible
future climate conditions.  Pielke and Guenni (1999) discuss
introducing a vulnerability perspective to assess what are the major
environmental threats to specific resources. With this information,
the climate community (and other members of the environmental science
community) can assess whether the stakeholder needs are predictable or
not. This approach would require that the SPM start with vulnerability
assessments, rather than introducing them at the end in the concept of
"impacts". 

The assessment of land-surface temperatures, which is the basis for
Figure 1 (page 8) in the SPM also ignores human-caused landscape
changes, except for urbanization. These changes can affect both the
local and regional temperature record as the landscape cover is
altered. Pielke et al. (1999), for example, explain the observed
warming and drying in July and August in south Florida as due to the
conversion of the natural landscape to its current human-dominated
form.  Pielke et al. (2000) documented substantial
spatial variation in temperature trends in eastern Colorado, some of
which are undoubtedly associated with landscape change this
century. Segal et al. (1988, 1989) and Stohlgren et al. (1998), for
example, document the major role of irrigation on the climate in this
region. Without considering how landscape change has influenced
Figure 1, why should it be concluded to be a representative measure of
temperature trends due to increased anthropogenic greenhouse gases and
aerosols?

We investigated global and regional temperature trends (Pielke et
al. 1998a,b; Chase et al. 2000b) using the 1000-850 mb thickness
values for the period 1979-1996 and, consistent with the MSU data,
found no consistent global temperature change in the lower troposphere
during this period. In contrast, Figure 1 shows warming. If each data
set are accurate, as implied by the recent NRC Panel on the
reconciliation of MSU and surface data, the radiative effect of
increased carbon dioxide and other greenhouse gases and aerosols must
be processed differently by the real climate system, than represented
in the GCMs.

In conclusion, as stated on page 1 of the SPM, "Climate Change in IPCC
Working Group 1 usage refers to any change in climate over time
whether due to natural variability or as a result of human activity."
Clearly, the IPCC has yet to fully deal with the range of forcings that can 
lead to climate change.

I would be glad to provide additional evidence for the conclusions in
this write-up.  I am copying these comments to the IPCC Co-Chairs,
coordinating lead authors of Working Group 1, and other interested
scientists.

REFERENCES

Chase, T.N., R.A. Pielke, T.G.F. Kittel, R. Nemani, and S.W. Running,
 1996: The sensitivity of a general circulation model to global
 changes in leaf area index.  J. Geophys. Res., 101, 7393-7408.

Chase, T.N., R.A. Pielke, T.G.F. Kittel, R.R. Nemani, and
S.W. Running, 2000a: Simulated impacts of historical land cover changes
on global climate in northern winter.  Climate Dynamics, 16, 93-105.

Chase, T.N., R.A. Pielke, J.A. Knaff, T.G.F. Kittel,
and J.L. Eastman, 2000b: A comparison of regional trends in 1979-1997
depth-averaged tropospheric temperatures. Int. J. Climatology,
in press.

Eastman, J.L., 1999:  Analysis of the effects of CO2
and landscape change using a coupled plant and meteorological model.
Ph.D. Dissertation, Atmospheric Science Paper No. 686, Colorado State
University, R.A. Pielke, P.I., 148 pp.

Eastman, J.L., M.B. Coughenour, and R.A. Pielke, 2000: The
effects of CO2 and landscape change using a coupled plant and
meteorological model. Global Change Biology, submitted.

Leemans, R., 1999: Land-use change and the terrestrial carbon
cycle. IGBP Global Change Newsletter,  37, 24-26.

O'Brien, K.L., 2000: Upscaling tropical deforestation: Implications
for climate change. Climatic Change, 44, 311-329.

Pielke, R.A., 1984: Earth sciences: Atmospheric sciences - 1983,
Encyclopaedia Britannica Yearbook of Science and the Future, 279-282.


Pielke, R.A. Sr., 2000: Overlooked issues in the U.S.
National Climate and IPCC assessments.  Preprints, 11th Symposium
on Global Change Studies, 80th AMS Annual Meeting, Long Beach, CA,
January 9-14, 2000, 32-35.

Pielke, R.A. Sr. and L. Guenni, 1999: Vulnerability
assessment of water resources to changing environmental
conditions. IGBP Global Change Newsletter,  39, 21-23.

Pielke, R.A., J. Eastman, T.N. Chase, and T.G.F. Kittel, 1998a:
1973-1996 trends in depth-averaged tropospheric temperature. 
J. Geophys. Res.,  103, 16927-16933. 

Pielke, R.  A., J. Eastman, T.N. Chase, J. Knaff, and T.G.F. Kittel,
1998b: Correction to ``1973-1996 trends in depth-averaged tropospheric
temperature''.  J. Geophys. Res., 103, 28909-28911.

Pielke, R.A., R.L. Walko, L. Steyaert, P.L. Vidale, G.E. Liston, and
W.A. Lyons, 1999: The influence of anthropogenic landscape changes on
weather in south Florida. Mon. Wea. Rev., 127, 1663-1673.

Pielke, R.A., T. Stohlgren, W. Parton, J. Moeny,
N. Doesken, L. Schell, and K. Redmond, 2000: Spatial
representativeness of temperature measurements from a single site. 
Bull. Amer. Meteor. Soc.,  81, 826-830.

Pitman, A.J., and M. Zhao, 2000: The relative impact of observed
change in land cover and carbon dioxide as simulated by a climate
model.  In preparation.

Pitman, A., R. Pielke, R. Avissar, M. Claussen, J. Gash, and
H. Dolman, The role of the land surface in weather and climate: Does
the land surface matter? IGBP Global Change Newsletter, 39, 4-11.

Segal, M., R. Avissar, M.C. McCumber, and R.A. Pielke, 1988:
Evaluation of vegetation effects on the generation and modification of
mesoscale circulations.  J. Atmos. Sci., 45, 2268-2292.
           
Segal, M., W. Schreiber, G. Kallos, R.A. Pielke, J.R. Garratt, J.        
Weaver, A. Rodi, and J. Wilson, 1989: The impact of crop areas
in northeast Colorado on midsummer mesoscale thermal
circulations.  Mon. Wea. Rev., 117, 809-825.
           
Shine, K.P., and P.M. de F. Forster, 1999: The effect of human
activity on radiative forcing of climate change: a review of recent
developments. Global Planet. Change, 20, 205-225.

Stohlgren, T.J., T.N. Chase, R.A. Pielke, T.G.F. Kittel,
and J. Baron, 1998: Evidence that local land use practices influence
regional climate and vegetation patterns in adjacent natural
areas. Global Change Biology,  4, 495-504.
 
Trenberth, K., 1999: Global climate project shows early promise. EOS,
80, 269-275.

Wang, G., and E.A.B. Eltahir, 2000a: Biosphere-atmosphere interactions
over west Africa 1. Development and validation of a coupled dynamic
model. Q. J. Roy. Meteor. Soc., in press.

Wang, G. and E.A.B. Eltahir, 2000b: Biosphere-atmosphere interactions
over west Africa 2. Multiple climate equilibria. Q. J. Roy. Meteor.
Soc., in press.



==============================================================================
Roger A. Pielke, Sr., Professor and State Climatologist
Department of Atmospheric Science, Colorado State University
Fort Collins, CO  80523, Phone/Fax: 970-491-8293
Email: dallas@cobra.atmos.colostate.edu
VISIT OUR WEBSITE AT: http://hercules.atmos.colostate.edu/~project

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

>From dallas@cobra.ATMOS.ColoState.EDU Wed May 10 21:16:35 2000
Date: Mon, 8 May 2000 14:37:01 -0600 (MDT)
From: Dallas McDonald <dallas@cobra.ATMOS.ColoState.EDU>
To: Mike MacCracken <mmaccrac@usgcrp.gov>
Subject: Chapter 10 review


Dear Mike,

Thank you for the opportunity to provide comments on Chapter 10:
Regional Climate Simulation -- Evaluation and Projections. Unfortunately,
I have very substantial concerns regarding the use of regional climate
models for predictions of climate change more than a season or so into
the future. My concerns can be summarized as follows.

*Neither the AOGCMs or the regional climate models include all of the
 significant human effects on the climate system (e.g., see page 22;
 lines 41-42 where this "very recent development" is discussed).  As I
 communicated to you in my comments on the SPM, the combined effects
 of human landuse change, the biogeochemical effect on the atmosphere
 due to increased CO2, and the microphysical effect of pollution
 aerosols, for example,  have not yet been included in these models. Thus the
 existing model runs should only be interpreted as sensitivity
 experiments, not forecasts, projections,  or even scenarios (Pielke 2000).


*The application of statistical and dynamic downscaling as applied to
 numerical weather prediction is a very appropriate and valuable tool
 to improve the spatial and temporal skill of weather
 projections. However, dynamic downscaling from the radiative effects
 of CO2 and aerosol AOGCM sensitivity experiments cannot provide
 improved skill for several reasons.

First, with respect to dynamic downscaling, there is not a feedback
upscale to the AOGCM from the regional model, even if all of the
significant large-scale (GCM scale) human-caused disturbances were
included.  The regional model runs reported in Chapter 10 themselves
are incomplete in their representation of regional human changes
(e.g., landuse change) and of biogeochemical effects.

The AOGCM also has a spatial resolution that is inadequate to properly
define the lateral boundary conditions of the regional model. As shown
by Anthes and Warner (1978), the lateral boundary conditions are the
dominant forcing of regional atmospheric models as associated with
propagating features in the polar westerlies. With numerical weather
prediction, the observations used in the analysis to initialize a
model retain a component of realism even when degraded to the coarser
model resolution of a global model.  This realism persists for a
period of time (up to a week or so), when used as lateral boundary
conditions for a regional numerical weather prediction model.  This is
not true with the AOGCMs where observed data does not exist to
influence the predictions. A regional model cannot reinsert model
skill, when it is so dependent on lateral boundary conditions, no
matter how good the regional model.

If this conclusion is disagreed with, the first step to demonstrate
that the regional climate model has predictive skill is to integrate
an atmospheric GCM with observed SSTs for several seasons into the
future. The GCM output would then be downscaled using the regional
climate model. There is expected to be some regional skill and this
needs to be quantified. This level of skill, however, will
necessarily represent the maximum skill theoretically even possible with 
AOGCMs as applied for forecasts years and decades into the future since,
for these periods, SSTs must also be predicted, and
not specified. Such experiments have not been systematically
completed.  Indeed, does the concept of predictive skill even make
sense when we cannot verify the models until decades into the future?

The statistical downscaling, besides requiring that the AOGCMs are
accurate predictions of the future, also require that the statistical
equations that are used for downscaling remain invariant under changed
regional atmospheric and land-surface conditions. There is no way to
test this hypothesis. In fact, it is unlikely to be valid since the
regional climate is not passive to larger-scale climate conditions,
but is expected to change over time and feedback to the larger
scales. More details of this concern regarding downscaling (and the
need to replace this approach with a vulnerability perspective) are
reported in Pielke and Guenni (1999).


The term "resolution" itself is erroneously used in the text (e.g.,
Appendix 10). As discussed by Pielke (1991) and Laprise (1992),
resolution of atmospheric (and also ocean) features in a model,
requires at least 4 grid increments in each spatial direction. The
listing of resolution as given in the Chapter's tables is
incorrect. The inappropriate use of the term resolution in the tables
implies a horizontal scale to the stakeholders that is actually too
small for the models to resolve. The more appropriate term to use in the
tables is "grid increment".

I would be glad to elaborate on my substantial concerns regarding
Chapter 10. The illusion of skill is presented in the Figures (e.g.,
more rainfall over the better resolved terrain), but since the results
are so dependent on lateral boundary conditions and AOGCMs which are
only sensitivity studies, the interpretation of the model results as
"projections" is erroneous and is a misleading communication to the
stakeholder community.

My recommendation is that the Chapter retain the application of high
resolution AOGCMs and the downscaling discussion for the current
climate, but add a new section where these tools are applied for
seasonal weather prediction using observed SSTs, in order to ascertain
how skillful the coupled models can predict seasonal weather. A final
section would then summarize regional climate sensitivity experiments
where the relative effect of regional human disturbance (e.g., 
the radiative and biological effect within the climate system of
increased CO2; landuse change -- both historical and estimates of
future possibilities; the radiative and biogeochemical effects of
air pollution, such as ozone, nitrogen deposition, etc.).  The knowledge
of these sensitivities would be much more useful to policymakers than
the existing very limited regional climate results, which are
inappropriately communicated as projections.  Since many decisions are
regional and local in scale, the understanding of the involvement of
the regional climate system within the entire spectrum of environmental
change and variability (and not just the radiative effect of increased
CO2 and aerosols) is a more effective methodology to protect society
from environmental threats.

REFERENCES

Anthes, R.A. and T.T. Warner, 1978: Development of hydrodynamic models
suitable for air pollution and other mesometeorological studies.
Mon. Wea. Rev., 106, 1045-1078.

Laprise, R., 1992: The resolution of global spectral models, 73,
1453-1454.

Pielke, R.A., 1991:  A recommended specific definition of
``resolution''.  Bull. Amer. Meteor. Soc.,  72, 1914.

Pielke, R.A. Sr., 2000: Overlooked issues in the U.S.
National Climate and IPCC assessments.  Preprints, 11th Symposium
on Global Change Studies, 80th AMS Annual Meeting, Long Beach, CA,
January 9-14, 2000, 32-35.

Pielke, R.A. Sr. and L. Guenni, 1999: Vulnerability
assessment of water resources to changing environmental
conditions. IGBP Global Change Newsletter,  39, 21-23.


==============================================================================
Roger A. Pielke, Sr., Professor and State Climatologist
Department of Atmospheric Science, Colorado State University
Fort Collins, CO  80523, Phone/Fax: 970-491-8293
Email: dallas@cobra.atmos.colostate.edu
VISIT OUR WEBSITE AT: http://hercules.atmos.colostate.edu/~project


