Monthly Archives: September 2008

Bettles and Climate – Another Climate Forcing

There was a news article by Randolph E. Schmid (AP Science Writer) last Wednesday (September 24, 2008) which highlights another climate forcing [thanks to Ben Herman to alerting us to this news article]. 

The article is titled

“Study looks at beetles’ effects on weather”

The article starts with the text “Can a plague of beetles change the weather?” and proceeds to answer this question in the affirmative.

The article continues with the text

“Vegetation affects local weather by absorbing or reflecting sunlight and releasing chemicals and moisture. Changes can influence such things as rainfall, temperatures and smog…..’Forests help control the atmosphere, and there’s a big difference between the impacts of a living forest and a dead forest,’ NCAR scientist Alex Guenther, a principal investigator on the project, said in a statement. ‘With a dead forest, we may get different rainfall patterns, for example,’ he added……Indeed, preliminary computer modeling suggests that beetle kills of large forest areas can lead to temporary temperature increases of 2-to-4 degrees Fahrenheit, the researchers said.”

This news article is a useful summary of this local (and mesoscale) climate forcing. The only misimpression in the article is the statement that

 “Living forests soak up carbon dioxide, while dead ones release it, potentially contributing to warming.”

Actually, while growing living forests (i.e. those increasing in biomass) can absorb more carbon than they emit during a year, dead trees from beetle kill may or may not release more carbon dioxide since it depends on whether the removal of the forest permits invigorated growth of new vegetation in the understory, as well as how rapidly the dead trees decompose.

Nevertheless, this is yet another example of the first order role of landscape change (both from natural and human management practices) on the climate system, that is summarized in

Pielke Sr., R.A., 2005: Land use and climate change. Science, 310, 1625-1626.


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“How Natural and Anthropogenic Influences Alter Global and Regional Surface Temperatures: 1889 to 2006″ by Lean and Rind, 2008

We would like to thank Timo Hämeranta for alerting us to a new paper 

Lean, Judith L., and David H. Rind, 2008. How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006. Geophys. Res. Lett., 35, L18701, doi:10.1029/2008GL034864.

The abstract reads

“To distinguish between simultaneous natural and anthropogenic impacts on surface temperature, regionally as well as globally, we perform a robust multivariate analysis using the best available estimates of each together with the observed surface temperature record from 1889 to 2006. The results enable us to compare, for the first time from observations, the geographical distributions of responses to individual influences consistent with their global impacts. We find a response to solar forcing quite different from that reported in several papers published recently in this journal, and zonally averaged responses to both natural and anthropogenic forcings that differ distinctly from those indicated by the Intergovernmental Panel on Climate Change, whose conclusions depended on model simulations. Anthropogenic warming estimated directly from the historical observations is more pronounced between 45°S and 50°N than at higher latitudes whereas the model-simulated trends have minimum values in the tropics and increase steadily from 30 to 70°N.”

In their Introduction, they write that

“Our results yield trends in the four individual global surface temperature components over the past 25, 50 and 100 years, augmenting the linear trends that IPCC reported in net global temperature for these same periods, and depicting the associated regional temperature trend patterns.”

There are several quite interesting statements in the article including

 “Contrary to recent assessments based on theoretical models [IPCC, 2007] the anthropogenic warming estimated directly from the historical observations is more pronounced between 45°S and 50°N than at higher latitudes…”

“Climate models may therefore lack – or incorrectly parameterize – fundamental processes by which surface temperatures respond to radiative forcings.”

” None of the natural processes can account for the overall warming trend in global surface temperatures. In the 100 years from 1905 to 2005, the temperature trends produce by all three natural influences are at least an order of magnitude smaller than the observed surface temperature trend reported by IPCC [2007].”

“In contrast with climate model simulations, the zonal surface temperature changes determined for natural (solar and volcanic) and anthropogenic influences from the historical surface temperature record do not increase rapidly from mid to high latitudes. Furthermore, since the temperature response to solar forcing occurs relatively rapidly (within months) with patterns that relate to existing tropospheric circulation patterns, the pathways likely involve dynamical motions not simply thermal processes that transfer heat to the deep ocean.”

The analysis presented in this paper provides an effective framework to seek to attribute reasons for long term climate trends. However, the use of the surface temperature data, with its range of uncertainties and biases; i.e. see

Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229


Lin, X., R.A. Pielke Sr., K.G. Hubbard, K.C. Crawford, M. A. Shafer, and T. Matsui, 2007: An examination of 1997-2007 surface layer temperature trends at two heights in Oklahoma. Geophys. Res. Letts., 34, L24705, doi:10.1029/2007GL031652.

is necessarily going to significantly alter their attribution study.

Climate Science recommends that a more robust study is for them to apply their analysis to the global average and regional pattern of tropospheric temperature variations and trends diagnosed in the UAH MSU and RSS MSU data, and in the upper ocean heat content data (see).

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You Have Got To Be Kidding……

The unusual snow and cold in South Africa that has occurred this week is reported as yet another example of global warming [thanks to Souleymane Fall for alerting us to this]; see

Warming has a hand in recent wild weather

where it is written

“The severe weather conditions experienced in South Africa in recent weeks are partially due to climate change.”

Additional articles on this weather event include  Roads close after snowfalls and Snow hits South Africa.  While clearly a single weather event does not inform us of what to expect in the future, the attribution of this cold and snow to global warming is yet another example of poor news reporting.

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Misconception And Oversimplification Of the Concept Of Global Warming By V. Ramanthan and Y. Feng

UPDATE September 26 2008: I have requested that Dr. Ramanathan write an unedited guest reply to the Climate Science weblog below, but so far have not had a response. If he accepts my invitation, Climate Science will promptly publish on this website.

There is a new paper by a eminent and distinguished climate scientist, Dr. Ramanathan in the Proceedings of the National Academy of Sciences. [Thanks to David Douglass for alerting us to this new paper!]. The paper is

 Ramanathan, V. and Y. Feng, 2008: On avoiding dangerous anthropogenic interference with the climate system: Formidable challenges ahead, PNAS, 105, 14245-14250, Sept 23, 2008.

with the abstract

“The observed increase in the concentration of greenhouse gases (GHGs) since the preindustrial era has most likely committed the world to a warming of 2.4°C (1.4°C to 4.3°C) above the preindustrial surface temperatures. The committed warming is inferred from the most recent Intergovernmental Panel on Climate Change (IPCC) estimates of the greenhouse forcing and climate sensitivity. The estimated warming of 2.4°C is the equilibrium warming above preindustrial temperatures that the world will observe even if GHG concentrations are held fixed at their 2005 concentration levels but without any other anthropogenic forcing such as the cooling effect of aerosols.The range of 1.4°C to 4.3°C in the committed warming overlaps and surpasses the currently perceived threshold range of 1°C to 3°C for dangerous anthropogenic interference with many of the climate-tipping elements such as the summer arctic sea ice, Himalayan–Tibetan glaciers, and the Greenland Ice Sheet. IPCC models suggest that ≈25% (0.6°C) of the committed warming has been realized as of now. About 90% or more of the rest of the committed warming of 1.6°C will unfold during the 21st century, determined by the rate of the unmasking of the aerosol cooling effect by air pollution abatement laws and by the rate of release of the GHGs-forcing stored in the oceans. The accompanying sea-level rise can continue for more than several centuries. Lastly, even the most aggressive CO2mitigation steps as envisioned now can only limit further additions to the committed warming, but not reduce the already committed GHGs warming of 2.4°C.”

I agree with Dr. Ramanthan that the addition of carbon dioxide into the atmosphere is a significant positive (warming) radiative forcing. Until the last few years, at least one of the global models (the GISS model projections) accurately simulated the long term upper ocean heat content; see

Comparison of Model and Observations Of Upper Ocean Heat Content.

Unfortunately, the Ramanthan and Feng PNAS paper does not use the more appropriate metric of ocean heat content changes as a diagnostic of global warming, but perpetuates a very significant misunderstanding of the Earth’s radiative fluxes by using the global average surface temperature anomaly.

When I served with Dr. Ramanthan on the 2005 National Research Council committee that produced the book

National Research Council, 2005: Radiative forcing of climate change: Expanding the concept and addressing uncertainties. Committee on Radiative Forcing Effects on Climate Change, Climate Research Committee, Board on Atmospheric Sciences and Climate, Division on Earth and Life Studies, The National Academies Press, Washington, D.C., 208 pp

we discussed the issue of “heat in the pipeline” and “unrealized heat” and I assumed we had come to an agreement on this. The term “committed warming” is not used in the 2005 NRC report.

As has been discussed on Climate Science; see

Can The IPCC Model Projections Of Global Warming Be Evaluated From Just Several Years Of Data?

A Litmus Test For Global Warming – A Much Overdue Requirement

A Global Warming Currency

Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335.

there is no “committed” heat in the climate system.

They are confusing the concept of “committed”heat with that of a non-equilibrium radiative imbalance.

What they are assuming is that the difference in the IPCC multi-decadal global model simulations from the radiatively unforced runs (i.e. no human-caused radiative forcing) and the radiatively forced runs is the “committed”  heat and that this will continue into the future.

 However, the IPCC models have not been shown to accurately predict the difference in incoming and outgoing radiative fluxes at the tropopause or surface in comparison with observed values of these fluxes.

This is why the ocean heat content changes are so useful as they provide a mechanism to diagnose this imbalance.

Dr. Ramanathan even agreed with this viewpoint in the 2005 National Research Council report which he co-authored. It is written on page 98 of that report

“The ocean is the largest heat reservoir in the climate system (Levitus et al., 2000, 2001). Thus, the change in ocean heat storage with time can be used to calculate the net radiative imbalance of the Earth (Ellis et al., 1978; Piexoto and Oort, 1992). In essence, the ocean heat content provides a metric for the integral in time of the TOA radiative forcing. Furthermore, it offers a valuable constraint on the performance of climate models (Barnett et al., 2001).”

In lieu of the more robust metric of global warming that is given by upper ocean heat content changes,  the “global average surface temperature” concept (e.g. see Equation 1-1 on page 19 in NRC 2005) is used by Ramanathan and Feng despite their recognition of its limitations.

The Ramanthan and Feng paper is, therefore, misleading. There is no “unrealized heat” or “heat in the pipeline”. What they must show is that the radiative imbalances are persisting in the observations

They misapply a concept that, while appropriate for a pot of water on the stove with a burner turned on to heat the pot,  is too simplistic to apply to the climate system for the following reasons:

1. The simple pot analog that Ramathan uses implicitly assumes a static climate system in which the radiative forcing is nearly constant (the “unforced” condition in the multi-decadal global climate model simulations).  This is clearly not true even on the annual time scale in which significant (over 30 Watts per meter squared) global average radiative imbalance occurs each year as a result of the different distance of the Earth from the Sun during the year; e.g. see

Ellis et al. 1978: The annual variation in the global heat balance of the Earth. J. Climate. 83, 1958-1962.

Ramanthan and Feng are basing their assumption on a long term nearly static radiative imbalance on models, not observations. This is a circular argument as the models are hypotheses only.

2. The use of the term global average surface temperature anomaly is misleading as, unlike a pot of water, the surface temperature anomaly is i)  spatially varying (e.g. see), ii) its effect on the radiative imbalance is proportional to temperature to its fourth power (T**4), e.g. see, and iii) the surface is often not thermodynamically coupled to the rest of the climate system including the troposphere (e.g. see Section 2 in

Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229.

3. The recent studies

Spencer, R.W., and W.D. Braswell, 2008: Abstract- Feedback vs. Chaotic Radiative Forcing: “Smoking Gun” Evidence for an Insensitive Climate System?      Download Powerpoint of presentation

Douglass, D.H., and J.R. Christy, 2008: Limits on CO2 Climate Forcing from Recent Temperature Data of Earth. Energy and Environment, accepted. [although not a standard journal, their analysis still needs to be responded to with respect to the Ramanathan and Feng paper]

as well as our analysis; see slide 27 in

have raised issues on the magnitude of the feedbacks, particularly atmospheric water vapor increases, but also snow and sea ice albedo decreases, which, according to the IPCC global models, are expected to amplify the positive radiative forcing of the well-mixed greenhouse gases, including carbon dioxide.

The dominant radiative feedback is supposed to be an increase in atmospheric water vapor, but, at most, this increase is muted; e.g. see

Climate Metric Reality Check #3 – Evidence For A Lack Of Water Vapor Feedback On The Regional Scale.

These feedbacks do not exist in a pot of water.

4. The statement by Ramanthan and Feng that “ IPCC models suggest that ≈25% (0.6°C) of the committed warming has been realized as of now” illustrates that they assume that the climate system has an equilibrium radiative balance, when in reality it does not. Moreover, they are using the IPCC models to evaluate how out-of-radiative-balance the climate system is, yet those models fail to adequately simulate the radiative feedbacks, nor even have all of the first order climate forcings. In the 2005 National Research Council report (on which Dr. Ramanathan was a co-author), it is written on page 100 that

“To date, all model projections of future climate have included a subset of climate forcings, typically greenhouse gas emission scenarios, solar variability, and more recently, aerosol emissions. As the diverse types of radiative and nonradiative climate forcings are recognized (e.g., aerosol indirect effects, changes in land cover), skillful projections of future global and regional climate will need to take them into account, an increasingly challenging task (Pielke Jr., 2001). Addressing this challenge may require a greater focus on assessing key societal and environmental vulnerabilities (Sarewitz et al., 2000).”

The recommendation that concludes the Ramanathan and Feng paper illustrates the inappropriate and societally negative consequences of their paper. They write at the end of their paper

 “Decisionmakers have to consider the tradeoffs between air pollution abatement and GHGs mitigation steps but they urgently need predictive tools for making such trade-offs rationally, informed fully of the consequences of policy actions, e.g., future climate changes caused by switching of fuel types, including switching to ethanol, bio diesel and other bio fuels; reducing SO2 emission without warming-offsetting emission reductions in black carbon, NOx, and CO2.”

This “tradeoff” is an seriously misleading recommendation. There are no tradeoffs with respect to air pollution abatement! Health benefits of reducing air pollution should be a worldwide goal irrespective of how it alters the global average radiative forcing.

Thus, the Ramanthan and Feng paper is misleading in both the science of the climate system and in its policy consequences. The science issues can be summarized as:

  • Their model of climate change (including global warming) using a single temperature global averaged anomaly is inadequate to properly diagnose global warming,
  •  the actual radiative feedbacks, based on observations, are more muted than simulated by the IPCC models, and
  • the climate system is not in radiative balance at any time.

My challenge to the authors of the PNAS report is the following. Tell us what accumulation in Joules you expect, based on the IPCC models, for the last five year, and for  each of the next ten years. How much more would the accumulation of Joules be without the negative radiative forcing of the aerosols? What is the spatial pattern of the changes in upper ocean heat content in Joules with time?

This then provides the benchmark with which we can compare to observations of ocean heat content changes in order to track what the authors claim is “committed” heating.

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“The Impact of Oklahoma’s Winter Wheat Belt on the Mesoscale Environment” by McPherson et al. 2004

Dr. Rene McPherson of the University of Oklahoma has contributed significantly to documenting the role of landscape processes as a first order climate forcing. This weblog is intended to provide much deserved recognition to her very important research on this subject.

In 2004, for example, she published an influential paper on the role of land management on the climate. The paper is

McPherson, R. A., D. J. Stensrud, and K. C. Crawford, 2004: The impact of Oklahoma’s wheat belt on the mesoscale environment. Mon. Wea. Rev., 132, 405–421.

The absract reads

“Oklahoma Mesonet data were used to measure the impact of Oklahoma’s winter wheat belt on the mesoscale environment from 1994 to 2001. Statistical analyses of monthly means of near-surface air temperatures demonstrated that 1) a well-defined cool anomaly existed across the wheat belt during November, December, January, February, and April, and 2) a well-defined warm anomaly existed across the wheat belt during June, July, and August. Data from crop year 2000 indicated a slight moist anomaly over the growing wheat from November 1999 through April 2000. In addition, based upon 21 000 daily statistics over eight unique years, statistical computations indicated less than a 0.1% chance that the moist anomaly during March resulted from random chance.

During the period from 1999 to 2001, about 50 days between 15 March and 1 May showed evidence of heightened values of daily maximum dewpoint over Oklahoma’s winter wheat belt as compared to adjacent grasslands. On more than half of these days, the dewpoint was enhanced only across five or six counties in north-central Oklahoma, where the winter wheat production was the largest. Another 90 days between 1 June and 31 July revealed a distinct warm anomaly in daily maximum air temperatures over the wheat belt, particularly across north-central Oklahoma.

These analyses demonstrate that Oklahoma’s winter wheat belt has a dramatic impact on the near-surface, mesoscale environment during its growth and after its harvest. Consequently, it is imperative that mesoscale forecasts, whether produced objectively or subjectively, account for the vegetation–air interactions that occur across western Oklahoma and, presumably, across other crop regions in the United States and around the globe.”

Additional publications from this well qualified climate scientist can be found on her website

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Climate Response And Radiative Forcing From Mineral Aerosols By Mahowald Et Al 2006

Climate Science has promoted the perspective that climate forcings involve much more than just the radiative forcing from carbon dioxide. This viewpoint is also emphasized in a National Research Council report

National Research Council, 2005: Radiative forcing of climate change: Expanding the concept and addressing uncertainties. Committee on Radiative Forcing Effects on Climate Change, Climate Research Committee, Board on Atmospheric Sciences and Climate, Division on Earth and Life Studies, The National Academies Press, Washington, D.C., 208 pp.

There was a paper in 2006 that investigated one of these issues; the role of mineral aerosols as a climate forcing. The paper is

Mahowald N. M., M. Yoshioka, W. D. Collins, A. J. Conley, D. W. Fillmore, D. B. Coleman (2006), Climate response and radiative forcing from mineral aerosols during the last glacial maximum, pre-industrial, current and doubled-carbon dioxide climates, Geophys. Res. Lett., 33, L20705, doi:10.1029/2006GL026126.

The abstract reads

“Mineral aerosol impacts on climate through radiative forcing by natural dust sources are examined in the current, last glacial maximum, pre-industrial and doubled-carbon dioxide climate. Modeled globally averaged dust loadings change by +88%, +31% and −60% in the last glacial maximum, pre-industrial and future climates, respectively, relative to the current climate. Model results show globally averaged dust radiative forcing at the top of atmosphere is −1.0, −0.4 and +0.14 W/m2 for the last glacial maximum, pre-industrial and doubled-carbon dioxide climates, respectively, relative to the current climate. Globally averaged surface temperature changed by −0.85, −0.22, and +0.06 °C relative to the current climate in the last glacial maximum, pre-industrial and doubled carbon dioxide climates, respectively, due solely to the dust radiative forcing changes simulated here. These simulations only include natural dust source response to climate change, and neglect possible impacts by human land and water use.”

In the conclusions, they write

“The net instantaneous top-of-atmosphere radiative forcing differences due to dust between the last glacial maximum, pre-industrial and doubled-carbon dioxide climates and the current climate are −0.53, −0.43, and +0.14 W/m2, respectively. If we include the impact of glaciogenic sources, the net top-of-atmosphere radiative forcing difference between the last glacial maximum and the current climate increases in magnitude to −1.04 W/m2. In the future we simulate a 0.14 W/m2 increase in radiative forcing because of a reduction in dust from carbon dioxide fertilization of the vegetation. It is uncertain that the carbon dioxide fertilization effect will continue in the future, when other nutrients may become limiting….”


” Despite the possible sensitivity of the results to our model specifications, our results suggest some interesting relationships across the different climate studies. Radiative forcing at the top-of-atmosphere and surface is linear with aerosol optical depth, even in different climates. Climate response in surface temperature and precipitation are roughly linear with aerosol optical depth in our model, with a decrease in both surface temperature and precipitation associated with increasing optical depth. Finally, our model predicts statistically significant decreases in temperature at many latitudes (not just close to the dust sources) when dust is added in the different climates, and a shift in precipitation from the northern part of the ITCZ to the southern part of the ITCZ.”

Mineral dust is yet another climate forcing that was inadequately assessed in the 2007 IPCC report. Mineral dust has a natural component (it occurred prior to any human disturbance of the landscape), and now has a human contribution through landscape degradation as a result of deliberate and inadvertent land management practices.

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A New Paper: “India’s Future Climate: No Cause for Alarm” by Dr. Madhav L. Khandekar

There is a very informative new article by Madhav Khandekar. It is

Khandekar, M.L., 2008: India’s Future Climate: No Cause for Alarm. i4d, August 2008, 24-26.

The abstract reads

“The most recent climate change documents of the IPCC (Intergovernmental Panel on Climate Change, a United Nations Body of scientists) project increasing frequency of extreme weather events like droughts/ floods, heat waves, escalating sea level rise etc. as the earth’s surface continues to warm due to increasing concentration of greenhouse gases (GHG) resulting from world-wide human activity. This article summarises the present state of the global warming and climate change science and concludes that for India as a whole, climate change impacts in future would be minimal and can be sustained with suitable adaptation strategy. The article further suggests (as an adaptation strategy) more efforts to be directed towards development of operationally useful technique for seasonal prediction of monsoon rainfall which is the most important climate event for the country as a whole”

with the conclusion

“The present debate on the global warming and climate change science has brought out several uncertainties in future projection of climate change and its world-wide impact. For India as a whole, future climate change impacts appear to be minimal and pose no concern for alarm at this point in time. The Indian summer monsoon has been and will remain the most important climate event for India in the foreseeable future. Future climate change impacts can be adequately sustained using suitable adaptation strategy. A useful adaptation strategy would be to develop and improve the present skill in seasonal prediction of summer monsoon with a lead time of few weeks to a few months. Improved skill in seasonal prediction will enable appropriate measures to be implemented which could minimise impacts of future droughts and floods in the Indian monsoon.”

This is important further evidence that adaptation to climate is essential, irregardless of how humans are altering the climate system.

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