September 2, 2007
The Climate Science Weblog has documented the following conclusions:
The needed focus for the study of climate change and variability is on the regional and local scales. Global and zonally-averaged climate metrics would only be important to the extent that they provide useful information on these space scales.
Global and zonally-averaged surface temperature trend assessments, besides having major difficulties in terms of how this metric is diagnosed and analyzed, do not provide significant information on climate change and variability on the regional and local scales.
Global warming is not equivalent to climate change. Significant, societally important climate change, due to both natural- and human- climate forcings, can occur without any global warming or cooling.
The spatial pattern of ocean heat content change is the appropriate metric to assess climate system heat changes including global warming.
In terms of climate change and variability on the regional and local scale, the IPCC Reports, the CCSP Report on surface and tropospheric temperature trends, and the U.S. National Assessment have overstated the role of the radiative effect of the anthropogenic increase of CO2 relative to the role of the diversity of other human climate climate forcing on global warming, and more generally, on climate variability and change.
Global and regional climate models have not demonstrated skill at predicting regional and local climate change and variability on multi-decadal time scales.
Attempts to significantly influence regional and local-scale climate based on controlling CO2 emissions alone is an inadequate policy for this purpose.
A vulnerability pespective, focused on regional and local societal and environmental resources of importance, is a more inclusive, useful, and scientifically robust framework to interact with policymakers, than is the focus on global multi-decadal climate predictions which are downscaled to the regional and local scales. The vulnerability paradigm permits the evaluation of the entire spectrum of risks associated with different social and environmental threats, including climate variability and change.
Humans are significantly altering the global climate, but in a variety of diverse ways beyond the radiative effect of carbon dioxide. The IPCC assessments have been too conservative in recognizing the importance of these human climate forcings as they alter regional and global climate. These assessments have also not communicated the inability of the models to accurately forecast the spread of possibilities of future climate. The forecasts, therefore, do not provide any skill in quantifying the impact of different mitigation strategies on the actual climate response
that would occur.
March 10, 2007
As initially announced on Climate Science where a discount is available (and as another plug for our book! :-)) The second edition of our book Human Impacts on Weather and Climate has appeared. There is both a hardback and a paperback version.
The summary of the book published by Cambridge University Press is,
“This new edition of Human Impacts on Weather and Climate examines the scientific and political debates surrounding anthropogenic impacts on the Earth’s climate and presents the most recent theories, data and modeling studies. The book discusses the concepts behind deliberate human attempts to modify the weather through cloud seeding, as well as inadvertent modification of weather and climate on the regional scale. The natural variability of weather and climate greatly complicates our ability to determine a clear cause-and-effect relationship to human activity. The authors describe the basic theories and critique them in simple and accessible terms. This fully revised edition will be a valuable resource for undergraduate and graduate courses in atmospheric and environmental science, and will also appeal to policy makers and general readers interested in how humans are affecting the global climate.
• Includes updated concepts and theories, new observational data, and modeling studies
• A generally non-mathematical presentation of scientific concepts and theories to appeal to a broad range of readers
• Discusses both inadvertent and planned weather modification
Contents
Part I. The Rise and Fall of the Science of Weather Modification: 1. The rise of the science of weather modification; 2. The glory years of weather modification; 3. The fall of the science of weather modification; Part II. Inadvertent Human Impacts on Regional Weather and Climate: 4. Anthropogenic emissions of aerosols and gases; 5. Urban-induced changes in precipitation and weather; 6. Other land-use/land-cover changes; 7. Concluding remarks; 8. Overview of global climate forcings and feedbacks; 9. Climatic effects and anthropogenic aerosols; 10. Nuclear winter; 11. Global effects of land-use/land-cover changes and vegetation dynamics; Epilogue; Index.
Reviews
The reviews that they list are,
“‘Contents-wise this is an excellent book … It is written with great honesty and courage, attacking many of the sacred tenets of weather modification and of climatic doomsday predictions.’ Meteorology and Atmospheric Physics
‘I can recommend the book to anyone concerned to understand the present debates with regard to climate change on both a local and global scale. The style of writing makes for easy reading, and the layout of the book is such that sections of particular interest can be found easily.’ Open University Geological Society Journal
‘… offers a valuable perspective that will be useful particularly for undergraduate courses in earth and atmospheric sciences. Students without a strong grounding in mathematics and physics will find this straightforward account quite approachable and welcome.’ International Journal of Climatology
‘ … a comprehensive, well-written, and highly interesting book. I strongly recommend it to all atmospheric scientists, to students in the atmospheric sciences, and to those in the environmental sciences interested in understanding weather and climate issues.’ Bulletin of the American Meteorological Society”
November 16, 2006
I presented a lecture at the 2005 the Golden Jubilee of the EPA/NOAA partnership in Durham, North Carolina entitled “The Partnership of Weather and Air Quality“.
The report version of my talk
Pielke Sr. R.A., 2006: The partnership of weather and air quality - An essay. Atmospheric Science Paper No. 770, Colorado State University, Fort Collins, CO 80523, 44 pp. is now available.
The abstract reads,
“As part of the celebration of the Golden Jubilee of the EPA/NOAA partnership, this paper provides a perspective on the movement towards a merger of the disciplines of weather and air quality science. Also presented are several major conclusions regarding the modeling of atmospheric dispersion, which have resulted in the use of combined knowledge from both disciplines These conclusions include the recognition that dispersion is greater than evaluated from Gaussian models in situations with significant large scale wind flow over heterogeneous landscapes, but overestimated in light wind conditions, particularly in heterogeneous landscapes.
Methodologies are proposed that would improve the ability to model the interactions of weather and air quality. These include the replacement of existing parameterizations with much more computationally efficient look-up-tables, the calculation of the linear and nonlinear components of the models separately, and use of wind tunnel modeling to improve the accuracy of the numerical models.”
The report includes discussion on the merger of research between traditional air quality studies and climate, since atmospheric chemistry and the dispersion of natural and anthropogenic aerosols into the atmosphere are integral components of the climate system [e.g. see the 2005 National Research Council Report: Radiative forcing of climate change: Expanding the concept and addressing uncertainties].
October 30, 2006
April 4, 2006
The text below was posted today as a preamble dated April 4 2006 on the Climate Science Weblog, where it will remain indefinitely. Constructive scientific comments that support or refute the conclusions listed are welcome.
The Climate Science Weblog has clearly documented the following conclusions since July 2005:
1. The needed focus for the study of climate change and variability is on the regional and local scales. Global and zonally-averaged climate metrics would only be important to the extent that they provide useful information on these space scales.
2. Global and zonally-averaged surface temperature trend assessments, besides having major difficulties in terms of how this metric is diagnosed and analyzed, do not provide significant information on climate change and variability on the regional and local scales.
3. Global warming is not equivalent to climate change. Significant, societally important climate change, due to both natural- and human- climate forcings, can occur without any global warming or cooling.
4. The spatial pattern of ocean heat content change is the appropriate metric to assess climate system heat changes including global warming.
5. In terms of climate change and variability on the regional and local scale, the IPCC Reports, the CCSP Report on surface and tropospheric temperature trends, and the U.S. National Assessment have overstated the role of the radiative effect of the anthropogenic increase of CO2 relative to the role of the diversity of other human climate climate forcing on global warming, and more generally, on climate variability and change.
6. Global and regional climate models have not demonstrated skill at predicting climate change and variability on multi-decadal time scales.
7. Attempts to significantly influence regional and local-scale climate based on controlling CO2 emissions alone is an inadequate policy for this purpose.
8. A vulnerability paradigm, focused on regional and local societal and environmental resources of importance, is a more inclusive, useful, and scientifically robust framework to interact with policymakers, than is the focus on global multi-decadal climate predictions which are downscaled to the regional and local scales. The vulnerability paradigm permits the evaluation of the entire spectrum of risks associated with different social and environmental threats, including climate variability and change.
November 4, 2005
RealClimate posted a comment today on Chaos and Climate.
My response, which I also submitted to RealClimate, is as follows:
James and William- your post, unfortunately, perpetuates the use of climate to refer to long term weather statistics. You state that
“The chaotic nature of atmospheric solutions of the Navier-Stokes equations for fluid flow has great impact on weather forecasting (which we discuss first), but the evidence suggests that it has much less importance for climate prediction.”
This is incorrect.
First, the more appropriate scientific definition of climate is that it is a system involving the oceans, land, atmosphere and continental ice sheets with interfacial fluxes between these components, as we concluded in the 2005 National Research Council report . Observations show chaotic behavior of the climate system on all time scales, including sudden regime transitions, as we documented in Rial, J., R.A. Pielke Sr., M. Beniston, M. Claussen, J. Canadell, P. Cox, H. Held, N. de Noblet-Ducoudre, R. Prinn, J. Reynolds, and J.D. Salas, 2004: Nonlinearities, feedbacks and critical thresholds within the Earth’s climate system. Climatic Change, 65, 11-38.
That the model simulations that you discuss in your weblog do not simulate rapid climate transitions such as we document in our paper illustrates that the models do not skillfully create chaotic behavior over long time periods as clearly occurs in the real world.
That climate is an integrated system and is sensitive to initial conditions is overviewed in Pielke, R.A., 1998: Climate prediction as an initial value problem. Bull. Amer. Meteor. Soc., 79, 2743-2746. Even within the atmospheric portion of the climate system, and applying a simple nonlinear model, based on the work of Lorenz, a chaotic response can be generated which is not evident in the model results you refer to (see Pielke, R.A. and X. Zeng, 1994: Long-term variability of climate. J. Atmos. Sci., 51, 155-159). We show in this study that even short-periodic natural variations of climate forcing can lead to significant long-term variability in the climate system.
We need to move the discussion to studying climate as a complex, nonlinear system which displays chaotic behavior if we are going to provide scientifically robust understanding to policymakers. Readers of your weblog are invited to read my postings at http://climatesci.colorado.edu if they would like to read a different perspective on climate science.
July 29, 2005
The different definitions of climate, have done much to confuse policymakers in the discussion of climate science.
The American Meteorological Society (AMS) definition of “climate change” is
“(Also called climatic change.) Any systematic change in the long-term statistics of climate elements (such as temperature, pressure, or winds) sustained over several decades or longer. Climate change may be due to natural external forcings, such as changes in solar emission or slow changes in the earth’s orbital elements; natural internal processes of the climate system; or anthropogenic forcing.”
The AMS defines anthropogenic forcing as
“Human-induced or resulting from human activities; often used to refer to environmental changes, global or local in scale.
The AMS defines the climate system as the
“system, consisting of the atmosphere, hydrosphere, lithosphere, and biosphere, determining the earth’s climate as the result of mutual interactions and responses to external influences (forcing). Physical, chemical, and biological processes are involved in the interactions among the components of the climate system.”
Here we have an inconsistency with the definition even by a very distinguished professional society! Climate, as defined by the AMS, is focused on the atmosphere, while the climate system consists of the atmosphere, hydrosphere, lithosphere, and biosphere. No wonder policymakers misapply this terminology.
As one example of the misuse by policymakers, the Royal Society released the following statement by Lord May:
“The science points to the need for a Herculean effort to make massive cuts in the amount of greenhouse gases that we pump into the atmosphere. So, while this encouraging new deal may play a role in this, it will only be part, and not all, of the solution.
“But we have serious concerns that the apparent lack of targets in this deal means that there is no sense of what it is ultimately trying to achieve or the urgency of taking action to combat climate change. And the developed countries involved with this agreement must not be tempted to use it as an excuse to avoid tackling their own emissions.”
“All eyes should be on the United Nations Framework Convention on Climate Change in Montreal at the end of November. Top of the agenda at this meeting should be the initiation of a study into what concentration of greenhouse gases in the atmosphere we can allow without suffering the most catastrophic effects of climate change. This would allow us to plan cuts in worldwide emissions accordingly and provide direction to such efforts to tackle what is the biggest environmental threat we face today.”
Here the conclusion is made that to “combat climate change” we must initiate “a study into what concentration of greenhouse gases in the atmosphere we can allow without suffering the most catastrophic effectsof climate change.”
Ignored in this statement is the role of the other anthropogenic climate forcings that we identified in the National Research Council report.
Lord May, President of the Royal Society, has clearly overlooked a very critical definition of what really constitutes the climate system and what the anthropogenic forcings and feedbacks are that influence climate. He is, unfortunately, cherrypicking climate science.
July 11, 2005
The title of this weblog is “Climate Science,” so the first thing we need to do is define “climate.” For many, the term refers to long-term weather statistics. However, on this blog we are adopting the definition that is provided in the 2005 National Research Council (NRC) report where the climate is the system consisting of the atmosphere, hydrosphere, lithosphere, and biosphere. Physical, chemical, and biological processes are involved in interactions among the components of the climate system. Figure 1-1 and 1-2 in the report illustrate this definition of climate very clearly. In the NRC report, climate forcings were extended beyond the radiative forcing of carbon dioxide to include the biogeochemical influence of carbon dioxide, but also a variety of aerosol forcings (see Table 2-2 in the report), nitrogen deposition, and land-cover changes. Each of these forcings has been determined to influence long-term weather statisitics as well as other aspects of the climate.
However, this concept of climate and its alterations by humans, has been generally ignored. The NRC report listed above certainly appears to have been incompletely missed by policymakers. As an example, at the G-8 meeting, the term “climate change” is used interchangably with “global warming.” However, the human influence on climate is much more complex and multi-dimensional than captured by the term “global warming” (see, for example, http://blue.atmos.colostate.edu/publications/pdf/R-260.pdf; http://www.nap.edu/books/0309095069/html/15.html and http://blue.atmos.colostate.edu/publications/pdf/R-225.pdf). The term “global warming” is generally used to refer to an increase in the globally-averaged surface temperature in response to the increase of well-mixed greenhouse gases, particularly CO2.
If, however, we are interested in atmospheric and ocean circulation changes, which, afterall is what creates our weather, we need to focus on how humans are altering these circulations. Ocean heat content changes are the much more appropriate metric than a globally-averaged surface temperature when evaluating “global warming” in any case (http://blue.atmos.colostate.edu/publications/pdf/R-247.pdf).
Thus it matters how we define climate and climate forcing (http://www.nap.edu/books/0309095069/html/15.html). By ignoring a number of the other first-order climate forcings, we are not properly addressing the threat we face in the future, but instead relying on the overly simplistic view of focusing on reductions in carbon dioxide emissions as the way to reduce our “dangerous intervention” in the climate. With respect to the changes of circulations, and therefore, weather, we need to identify and quantify the role of spatially heterogeneous climate forcings such as from aerosols and land-cover change, in addition to the influence of well-mixed greenhouse gases. These heterogeneous climate forcings could represent a more significant threat to our future climate system than the risk of an increase in the atmospheric concentration of CO2.
Hopefully, this blog will stimulate discussion, as well as illuminate reasons why this broader perspective on climate variability and change has been mostly ignored.
Weblog editor: Dallas Staley (dallas AT cires DOT colorado DOT edu)