Monthly Archives: August 2010

New Paper On The Role Of The Long Range Transport Of Mineral Dust And Other Aerosols By Ben-Ami Et Al 2010

In our paper

Pielke Sr., R., K. Beven, G. Brasseur, J. Calvert, M. Chahine, R. Dickerson, D. Entekhabi, E. Foufoula-Georgiou, H. Gupta, V. Gupta, W. Krajewski, E. Philip Krider, W. K.M. Lau, J. McDonnell,  W. Rossow,  J. Schaake, J. Smith, S. Sorooshian,  and E. Wood, 2009: Climate change: The need to consider human forcings besides greenhouse gases. Eos, Vol. 90, No. 45, 10 November 2009, 413. Copyright (2009) American Geophysical Union.

we presented evidence that the human role on the climate system is much broader than just that from the addition of carbon dioxide and other greenhouse gases to the atmosphere.

There is a new paper that provides further evidence of the role of aerosols (which in this study is a combination of natural and human effects) on the climate system. The paper also documents how this effect is transported across thousands of kilometers. This new research further confirms what was concluded in

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


“Several types of forcings—most notably aerosols, land-use and land-cover change, and modifications to biogeochemistry—impact the climate system in nonradiative ways, in particular by modifying the hydrological cycle and vegetation dynamics. Aerosols exert a forcing on the hydrological cycle by modifying cloud condensation nuclei, ice nuclei, precipitation efficiency, and the ratio between solar direct and diffuse radiation received.

The paper is

Ben-Ami, Y., Koren, I., Rudich, Y., Artaxo, P., Martin, S. T., and Andreae, M. O. 2010: Transport of North African dust from the Bodélé depression to the Amazon Basin: a case study, Atmos. Chem. Phys., 10, 7533-7544, doi:10.5194/acp-10-7533-2010

with the abstract

“Through long-range transport of dust, the North-African desert supplies essential minerals to the Amazon rain forest. Since North African dust reaches South America mostly during the Northern Hemisphere winter, the dust sources active during winter are the main contributors to the forest. Given that the Bodélé depression area in southwestern Chad is the main winter dust source, a close link is expected between the Bodélé emission patterns and volumes and the mineral supply flux to the Amazon.

Until now, the particular link between the Bodélé and the Amazon forest was based on sparse satellite measurements and modeling studies. In this study, we combine a detailed analysis of space-borne and ground data with reanalysis model data and surface measurements taken in the central Amazon during the Amazonian Aerosol Characterization Experiment (AMAZE-08) in order to explore the validity and the nature of the proposed link between the Bodélé depression and the Amazon forest.

This case study follows the dust events of 11–16 and 18–27 February 2008, from the emission in the Bodélé over West Africa (most likely with contribution from other dust sources in the region) the crossing of the Atlantic Ocean, to the observed effects above the Amazon canopy about 10 days after the emission. The dust was lifted by surface winds stronger than 14 m s−1, usually starting early in the morning. The lofted dust, mixed with biomass burning aerosols over Nigeria, was transported over the Atlantic Ocean, and arrived over the South American continent. The top of the aerosol layer reached above 3 km, and the bottom merged with the boundary layer. The arrival of the dusty air parcel over the Amazon forest increased the average concentration of aerosol crustal elements by an order of magnitude.”

As the climate system is investigated further, the shortcomings and incompleteness of the 2007 IPCC WG1 report become increasingly evident.

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Filed under Climate Change Forcings & Feedbacks, Research Papers

Futher Information On Tree Ring Proxy Data – A Research Paper García-Suárez Et Al 2009

In response to the post

Comment On Tree Ring Proxy Data and Thermometer Type Surface Temperature Anomalies And Trends

we have been alerted to an interesting paper on tree ring proxy data (h/t to Erik W!).

The paper is

García-Suárez et al, 2009: Climate signal in tree-ring chronologies in a temperate climate: A multi-species approach. Dendrochronologia 27 (2009)183–198

and the abstract reads

“Tree-rings can provide continuous yearly paleoclimatic records for regions or periods of time with no instrumental climate data. However, different species respond to different climate parameters with, for example, some sensitive to moisture and others to temperature. Here, we describe four common species growing in Northern Ireland and their suitability for climate reconstruction.

Our results suggest that beech and ash are the most sensitive to climate, with tree-ring widths more strongly influenced by precipitation and soil moisture in early summer than by temperature or sunshine. Oak is also sensitive to summer rainfall, whereas Scots pine is sensitive to maximum temperature and the soil temperature.

 We find that the moisture-related parameters, rainfall and the Palmer Drought Severity Index (PDSI), and to a lesser extent, maximum and mean temperatures, can be reconstructed. Reconstructions of climate parameters with tree-rings as proxies may be relatively stable for some seasons such as May–July. We find that combinations of species are more successful in reconstructing climate than single species.”

The conclusion has the text

“When reconstructing past climate from tree-rings (e.g. the amplitude of the Little Ice Age or Medieval Warm Period), it is important to appreciate that these reconstructions are conservative as they only contain a part of the true climate signal.”

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Comments On A Seminar “Modeling Watershed-Scale Distributions Of Snow For Present-Day And Future Climate” By Anne Nolin

There is a seminar today [August 23 2010] by Anne Nolin of the Department of Geosciences,  at Oregon State University, Corvallis

The seminar is titled “Modeling Watershed-Scale Distributions of Snow for Present-day and Future Climate in the U.S. Pacific Northwest Monday, 23 August 2010, 2:00 PM David Skaggs Research Center, Room 1D403.

After I present the abstract, I give several comments on this study, which is just one example of a type of climate study that has become common in recent years (i.e. one based on (unverifiable) multi-decadal global climate predictions).

The abstract reads

The snowmelt-dominated Cascade Mountains provide critical water supply for agriculture, hydropower, ecosystems, and municipalities throughout the Pacific Northwest. Empirical analyses and models of projected climate change show rising temperatures in the region. This temperature trend is accompanied by a shift from snowfall to rainfall at lower elevations and earlier snowmelt. In this study we model the spatial distribution of Snow Water Equivalent (SWE) in the McKenzie River Basin, Oregon (3000 km2). We use the physically based SnowModel with a grid resolution of 100 m and a daily time step. Model inputs include meteorological data, a digital elevation model, and land cover information. We compute the ratio of SWE to total winter precipitation (SWE/PRE) for the period of 2000-2009. The model is evaluated using point-based measurements of SWE, precipitation, and temperature and spatially, using snow cover extent from the MODIS instrument. SnowModel simulations are in very good agreement with measured SWE for most stations with Nash-Sutcliffe model efficiency values exceeding 0.9 in most cases. Agreement with MODIS snow cover data show a total difference of 7.1% at the time of peak SWE with the largest difference in valley bottoms (where vegetation is dense and snow cover is difficult to view with the satellite data).

For the future climate scenarios, meteorological inputs are perturbed based upon downscaled Intergovernmental Panel on Climate Change model predictions. The temperature and precipitation forcing data for 2000-2009 were perturbed to represent projected climate changes based on a composite of nineteen IPCC climate models (scenario A1B) downscaled to the Pacific Northwest region for the period 2030-2050. These perturbations were computed using the change from present-day climate to a projected future climate (delta value). The delta value was applied to daily temperature and precipitation data using a prescribed monthly value and the model was rerun using these perturbed values. Our perturbed simulations show substantial losses in SWE throughout the watershed. However, interannual variability under projected climate change can generate increases in SWE at high elevations but overall declines in basin-wide SWE. Thus, while there is a significant loss of snow covered area and volumetric water storage in the form of snow, the spatial changes in SWE are highly heterogeneous. This has important implications for runoff predictions as well as for design and implementation of snow monitoring networks.”

Here are my comments:

1. Her  evaluation of the snow distributions for the period 2000-2009 is solid science.

2. The extrapolation into the future using IPCC model predictions downscaled to the region of study, however, is not scientifically sound. First, even with current climate, the global climate models have shown no skill at predicting regional skill more than a season at most into the future. These global models are not able to skillfully simulate such regional circulation patterns as the Pacific Decadal Oscillation and ENSO, which are known to have a major effect on the weather in Oregon.

3. The packaging of her results in time periods (i.e. 2030-2050) is inappropriate and misleading to policymakers. 

4. Such unverifiable multi-decadal predictions based on the IPCC global models (as exemplified by this seminar) are  being supported by the NSF and other agencies, and are being published in the literature. Such studies, where the results are presented as forecasts rather than climate process studies,  were not funded before the last 10-15 years or so.

5. My recommended approach is to adopt the perspective that is summarized in the post

A Way Forward In Climate Science Based On A Bottom-Up Resourse-Based Perspective

where with respect to water resources the framework would read

“The vulnerability concept requires the determination of the major threats to water resources from climate, but also from other social and environmental issues. After these threats are identified for each resource, then the relative risk from natural- and human-caused climate change (estimated from the GCM projections, but also the historical, paleo-record and worst case sequences of events) can be compared with other risks in order to adopt the optimal mitigation/adaptation strategy.”

This is a much more inclusive approach than the limited narrowly focused approach presented in the second part of Anne Nolin’s seminar.

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Filed under Climate Science Misconceptions, Climate Science Presentations

Meeting September 7-9 2010 “Surface Temperature Datasets For The 21st Century” Chaired By Peter Thorne

There is a meeting scheduled September 7-9 2010 in the United Kingdom in Exeter titled

Surface temperature datasets for the 21st Century

This meeting has a set of white papers to frame the meeting.

However, at the very start of the meeting, it presents the bias of the organizers of this meeting as they write

“To meet 21st Century requirements it is necessary to reconsider our analyses of historical land surface temperature changes. This is about much more than simply re-engineering existing datasets. These datasets were adequate for assessing whether climate was changing at the global scale. This current exercise should not be interpreted as a fundamental questioning of these previous efforts. But these pre-existing datasets cannot answer all the questions that society is now quite rightly asking. They do not constitute a sufficiently large sample to truly understand our uncertainty at regional scales. At monthly resolution they are also of limited utility in characterising extremes in climate and their changes.”

The  statement that “These datasets were adequate for assessing whether climate was changing at the global scale“, yet “They do not constitute a sufficiently large sample to truly understand our uncertainty at regional scales” is scientifically flawed. The global average trends are composed of the summation of the regional trends!  The data cannot be adequate on the global scale (as an average) but not on the regional scale.

While, we need to wait to see what they actually accomplish at this meeting, the above statement indicates the organizers are persisting in assuming any regional variations are random and that a clear signal emerges when the surface temperature data are globally averaged.  More generally, they appear to be ignoring research that conflicts with their findings.

The Chair of the organizing committee is Peter Thorne and the other members are listed here along with the agenda. This committee includes John Christy, so there will be some ability to present alternative views of the surface temperature trend data.  However, a number of the attendees already have shown a bias in their viewpoints and even explicit successful attempts to suppress alternative viewpoints (e.g. Tom Peterson who is now President Commission of Climatology and NOAA NCDC Chief Scientist and Peter Thorne who is Chair of this meeting and now also works at NOAA NCDC).

I propose a litmus test to ascertain if this meeting is just another exercise by these scientists to endorse the analyses that they have already reported on in the 2007 IPCC WG  and the CCSP reports, or is finally an honest attempt to examine the existing biases and uncertainties.  One test will be how they respond to the peer-reviewed issues we raised in our papers

Klotzbach, P.J., R.A. Pielke Sr., R.A. Pielke Jr., J.R. Christy, and R.T. McNider, 2009: An alternative explanation for differential temperature trends at the surface and in the lower troposphere. J. Geophys. Res., 114, D21102, doi:10.1029/2009JD011841.

Klotzbach, P.J., R.A. Pielke Sr., R.A. Pielke Jr., J.R. Christy, and R.T. McNider, 2010: Correction to: “An alternative explanation for differential temperature trends at the surface and in the lower troposphere. J. Geophys. Res., 114, D21102, doi:10.1029/2009JD011841″, J. Geophys. Res., 115, D1, doi:10.1029/2009JD013655

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.

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, 2009: Reply to comment by David E. Parker, Phil Jones, Thomas C. Peterson, and John Kennedy on “Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 114, D05105, doi:10.1029/2008JD010938.

If they ignore these papers and others papers by our colleagues (e.g. McIntyre et al 2010), or dismiss them without a thorough rationale why, this will confirm that this meeting is just a self-justification exercise. If they seriously consider this other work, however, it would be an important step forward to achieving a more robust land temperature assessment.  I am not optimistic, unfortunately.

Finally, we will be reporting on several new papers in the coming weeks and months that will provide further documentation of the serious issues with the use of the land surface temperature  data to assess multi-decadal trends. This will include the quantitative analysis of the well- and poorly- sited USHCN sites that Anthony Watts and volunteers have been instrumental in surveying. 

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Filed under Climate Science Meetings, Climate Science Misconceptions

Comments By Hans Schellnhuber On Climate Science

There has been recent comments regarding the views of Hans Schellnhuber on climate science, who is a major advisor on climate issues with the German government; i.e. see

Schellnhuber in Der Spiegel

H.J. Schellnhuber Interview in English translation

In 2003, I co-authored a paper with Hans and feel it is useful to post on this paper today, including several extracts from the text that he agreed with. The article is

Pielke, R.A. Sr., H.J. Schellnhuber, and D. Sahagian, 2003: Non-linearities in the Earth system. Global Change Newsletter, No. 55, 11-15.

Excerpts read

“On all time scales, the various non-linear interactions are characterised by drivers and responses that are not proportional. Changes in state are often episodic and abrupt, and multiple equilibria commonly exist. One consequence of such a non-linear system is that forecasts based on current modelling tools should be viewed sceptically. For example, since none of the general circulation models (GCMs) used to project climate change over the next hundred years include all of the important forcings and feedbacks, they should be considered as sensitivity studies rather than forecasts [10]. In Earth System science, climate is not the long term average of weather statistics, but involves the non-linear interactions between the atmosphere, oceans, continental ice, and land surface processes, including vegetation, on all time scales.”

“Research to-date has revealed the need to establish the limits to predictability within the Earth System. It has been shown that climate prediction needs to be treated as an initial value problem with chaotic behaviour. This perspective acknowledges that beyond some time period, our ability to provide reliable quantitative and detailed projections of climate must deteriorate to a level that no longer provides useful information to policymakers.”

These views present a much less certain view in the understanding of the climate system, and the ability to skillfully predict climate in the coming decades than has been presented by Hans in his Die Spiegel article.

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Filed under Climate Science Reporting, Research Papers

Comment On Tree Ring Proxy Data and Thermometer Type Surface Temperature Anomalies And Trends

There was an interesting conclusion in a New York Times article on the relationship between tree ring proxy temperature trend analyses and thermometer type measures of temperature anomalies and trends.  The article is

British Panel Clears Scientists  by Justin Gillis published on July 7, 2010

The relevant text is on page 2 it is written

“But they were dogged by a problem: Since around 1960, for mysterious reasons, trees have stopped responding to temperature increases in the same way they apparently did in previous centuries. If plotted on a chart, tree rings from 1960 forward appear to show declining temperatures, something that scientists know from thermometer readings is not accurate.”

There are, however, problems with this conclusion. Since the thermometers are not coincident in location with the tree ring data (in the same local area), it would not be surprising that they are different. Indeed, this is yet another example that implies unresolved biases and uncertainties in the surface temperature thermometer type data as we discussed in several of our papers (see and see), as the thermometers are measuring elsewhere then where the proxy tree data is obtained.  This obvious issue has been ignored in the assessment of this so-called divergence between the two methods to evaluate temperature anomalies and trends.

It is possible, of course, that the trees are responding differently due to the biogeochemical effect of added carbon dioxide and/or nitrogen deposition. Nonetheless, to accept the thermometer record as the more robust measurement of spatial representative temperatures is premature.

I have discussed this issue further in the posts

Comments On The Tree Ring Proxy and Thermometer Surface Temperature Trend Data

December 2007 Session ‘The “Divergence Problem’ In Northern Forests

A New Paper On The Differences Between Recent Proxy Temperature And In-Situ Near-Surface Air Temperatures

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Recommended Book “The Climate Fix” By Roger A. Pielke Jr.

Most readers of my weblog also probably read that of my son’s [].  For those who do not, however, I am reposting his announcement of yesterday;

Free Preview of The Climate Fix

I have read the book and it should be read by everyone who is interested in climate science and climate policy. I 100% support his recommended path forward.

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Filed under Books, Research Papers