Monthly Archives: October 2005

Is Nitrogen Deposition a First-Order Climate Forcing?

The answer appears to be yes.

The 2005 National Research Council report on page 96 specifically stated the following,

“Several nonradiative forcings involve the biological components of the climate system”

with one type of summarized as,

“Biogeochemical forcing involves changes in vegetation biomass and soils. For example, increased nitrogen deposition caused by greater anthropogenic emissions of ammonia (NH3), nitric oxide (NO), and nitrogen dioxide (NO2) is a biogeochemical forcing of the climate system (Holland et al., 2005; Nitrogen deposition onto the United States and Western Europe: A synthesis of observations and models. Ecological Applications, 15, 38-57). This deposition has altered the functioning of soil, terrestrial vegetation, and aquatic ecosystems worldwide. Galloway et al. (2004; Nitrogen cycles: Past, present and future. Biogeochemistry 70:153-226). document that human activities increasingly dominate the nitrogen budget at the global scale and that fixed forms of nitrogen are accumulating in most environmental reservoirs.”

This biogeochemical forcing results in significant alterations in the physical components of the climate system such as the surface albedo, and the partioning of atmospheric turbulence into sensible and latent heat components, which subsequently affects all other aspects of the climate system

A seminar was presented October 6, 2005 at Colorado State University that summarized the current knowledge of nitrogen deposition, The informative abstract is,

“Using Observations and Models to Understand Biosphere-Atmosphere
Nitrogen and Sulfur Cycles

by Elisabeth A. Holland
NCAR Atmospheric Chemistry Division

The global nitrogen cycle has been profoundly perturbed during the industrial era through fossil fuel combustion and agricultural intensification. The atmospheric deposition networks designed to address the impact of acid rain deposition onto rural and remote areas in the some most industrialized regions of the world provides a key data set with adequate temporal and spatial coverage to understand the changing global nitrogen cycle. The measurements were made by the National Atmospheric Deposition Program and National Trends Network (NADP/NTN) and European Monitoring for the Environment Programme (EMEP).

To construct continental scale N budgets, we produced maps of N deposition fluxes from site-network observations for the US and Western Europe. The maps and analyses are necessarily restricted to the network measured quantities and consist of statistically interpolated fields of aqueous NO3- and NH4+, gaseous HNO3 and NO2 (in Europe), and particulate NO3- and NH4+. Western Europe receives five times more N in precipitation than the conterminous US. Estimated N emissions exceed measured deposition in the US by 5.3-7.81 Tg N. In Europe, estimated emissions better balance measured deposition, with an imbalance of between -0.63 to 2.88 Tg N suggesting that much of the N emitted in Europe is deposited there. Taking the imbalances in the two regions, more 50% of the N emitted in the US is exported from the continent, and some of the exported N may fall on Western Europe.

We examined the 25 year record of precipitation removal of a atmospheric nitrogen, ammonium and nitrate, using a seasonal trend LOESS statistical approach . On a continental scale for both the US and Western Europe, there was little overall trend in ammonium or nitrate wet deposition. The lack of a clear trend suggests that the emissions of ammonia and nitrogen oxides over the time period between 1978 and 2003 have been relatively constant. By contrast, sulfur dioxide deposition has decreased by as much as 50% over the same time period. There has been a clear difference in the effectiveness of a series of Transboundary Air Pollution Agreements and Clean Air Acts targeting the emissions of sulfur and nitrogen oxides. The Clean Air Acts have been successful at reducing sulfur dioxide emissions but have not been successful at reducing nitrogen oxide emissions.

These spatially and temporally explicit N deposition budgets and N and S trend analyses provide key tools for verifying regional and global models of atmospheric chemistry and transport, and represent critical inputs into terrestrial models of biogeochemistry.”

The modeling of the influence on long-term weather due to nitrogen deposition is in its early infancy. However, even now it needs to be recognized that this non-radiative biogeochemical climate forcing must be accounted for in any assessment of the relative and absolute role of the diversity of different human climate forcings.

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What is the Butterfly Effect?

There is a popular notion that the “butterfly effect” describes a climate system that is exceptionally sensitive to very small perturbations. As just one example, a google search turned up the following description of it,

“In the arcane field of chaos theory, there is what scientists call “the butterfly effect,” the popular notion that when a butterfly flaps its wings in Asia the action may eventually alter the course of a tornado in Kansas.” (

Even the scientific community presents this perspective, e.g., see, from which the following text is extracted,

“The ‘Butterfly Effect’, or more technically the “sensitive dependence on initial conditions”, is the essence of chaos……..The “Butterfly Effect” is often ascribed to Lorenz. In a paper in 1963 given to the New York Academy of Sciences he remarks: ‘One meteorologist remarked that if the theory were correct, one flap of a seagull’s wings would be enough to alter the course of the weather forever.’ By the time of his talk at the December 1972 meeting of the American Association for the Advancement of Science in Washington, D.C. the sea gull had evolved into the more poetic butterfly – the title of his talk was ‘Predictability: Does the Flap of a Butterfly’s Wings in Brazil set off a Tornado in Texas?’ In the applet we also see a second incarnation of the Butterfly – the amazing geometric structure discovered by Lorenz in his numerical simulations of three very simple equations that now bear his name.”

The solution of the Lorenz equations from this informative website illustrates the “butterfly” looking field that results. Figure 6 from Tsonis and Elsner (1989) has a particularly clear illustration of the butterfly solution.

This second definition of the butterfly effect is the correct use of the term “butterfly effect.” However, the first usage of the “butterfly effect” in that “when a butterfly flaps its wings in Asia the action may eventually alter the course of a tornado in Kansas” is incorrect. The information from the butterfly is quickly lost on scales close to the size of the butterfly, as the atmosphere is a dissipative system such that only particularly significant powerful forcings, or small climate forcings near a climate transition (but certainly not as small as a butterfly’s flapping winds) can upscale (i.e., teleconnect) to the global scale. Indeed, if we accepted the first definition of the “butterfly effect”, everything that an individual human does on any scale (e.g., brushing your teeth) would be a climate forcing that would influence weather thousands of kilometers away. Of course, that is preposterous.

To communicate accurately in climate science, we need to make sure we properly present the significance of Lorenz’s seminal research. There certainly are thresholds (i.e., “tipping points”) that can result in sudden and large changes in climate regimes. This is a characteristic of chaotic nonlinear systems which we discuss for example, in

Pielke, R.A., 1998: Climate prediction as an initial value problem. Bull. Amer. Meteor. Soc., 79, 2743-2746.644.

Zeng, X., R.A. Pielke, and R. Eykholt, 1993: Chaos theory and its applications to the atmosphere. Bull. Amer. Meteor. Soc., 74, 631-644.

Pielke, R.A. and X. Zeng, 1994: Long-term variability of climate. J. Atmos. Sci., 51, 155-159.

Zeng., X. and R.A. Pielke, 1993: What does a low-dimensional weather attractor mean? Phys. Lett. A., 175, 299-304.

The consequences of this chaotic nonlinearity is the ocureence of the concept of critical thresholds which we discuss 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.

The flap of a butterfly’s wings, however, while it seeks to capture the concept of the “sensitivity of the climate system to small perturbations of the initial conditions” overstates the true characteristic of the Earth’s climate system.

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Was the Arctic 2005 Summer the Warmest in 400 Years?

An ABC news release had the following,

“POINT BARROW, Alaska, Sept. 27, 2005 — This season has ushered in the warmest Arctic summer in 400 years. A NASA report to be released this week finds the polar ice pack has shrunk by nearly 30 percent since 1978, and new satellite photos show the melting is speeding up.? (

When I read this I was stunned, as I did not know we had measurements that covered the Arctic for the past 400 years. (We don’t!)

To provide a perspective on this claim, we can use the available long-term weather data.

Thanks to Kelly Redmond, of the Western Regional Climate Center (WRCC) who provided a set of links to NOAA’s Climate Diagnostic Center’s and the WRCC’s excellent long-term weather analyses!

Anomaly analyses can be constructed for a wide variety of weather variables, display formats and time periods from their information. I recommend these links to anyone interested in following the climate in near-real time.

Monthly and Seasonal Composites

Create a monthly or seasonal time series of climate variables

Global temperature time series

Alaska Climate Summaries

Alaska Temperature Actual vs. Normal Maximum/Minimum Last 365 Days

Since 400 years of data are not available from any of these data sources, we can view the plots for selected recent time periods to determine how atypical this past summer was. I have selected Barrow as an example of surface temperatures for one region (northern Alaska) for this past year,

While, the last 365 days of the period presented were warmer than average, it was near the average for much of the summer, except for a warm peak in early August. The other northern Alaskan station indicated a warmer than average summer, but not obviously exceptional. However, these data are for a limited area of the Arctic and do not present the anomalies in terms of departures from the average over the entire Arctic basin.

The NCEP Reanalyses can be used for this purpose. The plot of the NCEP Reanalysis surface temperature anomaly data for June to July for each year since 1948 for the 70°N to 90°N latitudes shows a clear warming signal with 2005 the warmest in the period since 1948, but a period in the 1950s is almost as warm. This surface temperature analysis indicates that the 2005 June-July period in the Arctic (from 70°N to the Pole) was the warmest in the last 57 years. The second warmest was in the early 1950s.

The NCEP Reanalysis tropospheric temperature anomaly data for June to July since 1948 for the 70°N to 90°N latitudes, however, provides a different result. There is no clear long-term trend at 500 hPa with the 1950s, on average appearing warmer than the 1990s! A similar pattern of a warm 1950s is evident at 700 hPa and at 850 hPa. At none of these atmospheric levels was 2005 the warmest in the period of record. There are also considerable spatial variations in the locations with warm and cold anomalies as can be constructed from the website

Thus the ABC News article started their article with an unambiguous statement that this past summer was the warmest in 400 years, but without substantiation and qualification. ABC News has biased its reporting with this overstatement. Clearly above the surface, 2005 was not the warmest June-July period in the last 57 years, much less the last 400. Also, since the tropospheric and surface temperature anomalies should be closely correlated with each other at this time of the year, there is an issue with the robustness of the surface temperature information to assess long-term temperature trends. Our blog of July 11, 2005 discussed issues with the surface temperature trends. A new peer-reviewed paper on another problem with using surface temperature data to assess large-scale, long-term temperature trends will also be reported on this weblog soon.

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Overlooked Issues in Prior IPCC Reports and the Current IPCC Report Process: Is There a Change From the Past?

Unfortunately, the answer is No.

The Intergovernmental Panel on Climate Change (IPCC) Working Group I: The Physical Basis of Climate Change? is soliciting expert reviews from September 12 to November 4, 2005 ( The chapter outline of the report topics is given below:

Historical Overview of Climate Change Science
Changes in Atmospheric Constituents and in Radiative Forcing
Observations: Surface and Atmospheric Climate Change
Observations: Changes in Snow, Ice and Frozen Ground
Observations: Oceanic Climate Change and Sea Level
Couplings Between Changes in the Climate System and Biogeochemistry
Climate Models and their Evaluation
Understanding and Attributing Climate Change
Global Climate Projections
Regional Climate Projections

Previous IPCC reports suffered from a much too narrow focus on the issue of climate change, and unfortunately, this IPCC report perpetuates that perspective. For example, biogeochemistry is not actually separate from the climate system as indicated in the IPCC chapter outline, but part of the climate system as was concluded in the 2005 National Research Council (NRC) Report . The diversity of climate forcings that were described in the NRC (2005) report (see Figure ES-1 in that report) is also not evident in the chapter topics.

In disappointment on the focus of prior IPCC reports (and also the U.S. National Assessment), I completed an article on this subject in 2002 for the journal Climatic Change. Steve Schneider, Editor of the journal, is acknowledged and thanked for permitting this essay to be published, and to promote constructive dialog on this subject. The article is

Pielke Sr., R.A., 2002: Overlooked issues in the U.S. National Climate and IPCC assessments. Climatic Change, 52, 1-11. A constructive counterpoint article by Mike MacCracken followed mine (MacCracken, M., 2002: Do the uncertainty ranges in the IPCC and U.S. National Assessments account adequately for possibly overlooked climatic influences. Climatic Change, 52, 13-23. ).

Unfortunately, the issues that are raised in my article in Climatic Change are being ignored in the construction of the IPCC outline of chapters. The IPCC Chapter outline perpetuates the same narrow perspective that was in the earlier reports.

Indeed, even more substantively, the IPCC should consider whether a new paradigm is needed and would better serve policymakers. In my Climatic Change essay, a “vulnerability assessment approach… which the entire spectrum of environmental stresses are evaluated in order to determine the greatest threats to specific resources”? was proposed. This vulnerability perspective is expanded on in Pielke Sr., R.A., J.O. Adegoke, T.N. Chase, C.H. Marshall, T. Matsui, and D. Niyogi, 2005: A new paradigm for assessing the role of agriculture in the climate system and in climate change. Agric. Forest Meteor. Only once the vulnerabilities are assessed, should the “global climate projections�? be introduced as just one of the tools to determine the possibilities of what could happen in the future. Our earlier weblogs under the topic “vulnerability paradigm”?, as well as Chapter E in Kabat, P., Claussen, M., Dirmeyer, P.A., J.H.C. Gash, L. Bravo de Guenni, M. Meybeck, R.A. Pielke Sr., C.J. Vorosmarty, R.W.A. Hutjes, and S. Lutkemeier, Editors, 2004: Vegetation, water, humans and the climate: A new perspective on an interactive system. Springer, Berlin, Global Change – The IGBP Series, 566 pp, discuss this viewpoint further.

The format of the request for input to the new IPPC report clearly illustrates the limited scope of the authors. While input is requested on the 11 chapter topics, there is no framework to provide input on whether the chapter format that they have chosen is even what is needed by the scientific community and by policymakers! From their request for reviews of the Chapter, we are to just accept the chapter topics that they have selected.

There is no other conclusion, but that the IPCC continues to work as an advocate that will continue to communicate a very parochial view of climate science to policymakers.

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Assessment of Coldest Northern and Southern Hemisphere 500 hPa Temperatures

We published two papers on the trends in the area of the coldest 500 hPa temperatures in the Northern Hemisphere (equal to or less than -40C) and the reason why the temperatures do not become colder than just below -40C.

Chase, T.N., B. Herman, R.A. Pielke Sr., X. Zeng, and M. Leuthold, 2002: A proposed mechanism for the regulation of minimum midtropospheric temperatures in the Arctic. J. Geophys. Res., 107(D14), 10.10291/2001JD001425.

Tsukernik, M., T.N. Chase, M.C. Serreze, R.G. Barry, R. Pielke Sr., B. Herman, and X. Zeng, 2004: On the regulation of minimum mid-tropospheric temperatures in the Arctic. Geophys. Res. Letts., 31, L06112, doi:10.1029/2003GL018831.

We found no long-term trend in the area covered by the coldest 500 hPa temperatures between 1950 and 1998. In response to the claims by the media and some scientists that the arctic climate is undergoing rapid climate change, the weblink listed below, prepared by Ben Herman and Mike Leuthold of the University of Arizona is particularly valuable.

If the Arctic climate is changing, in parallel with the reduction in the area of Arctic sea ice, we should see evidence of this in the time of onset, maximum area achieved, and end time in the spring of the area of the coldest temperatures in the mid-troposphere.

The 2005/2006 analyses can be followed in real-time on this web site.

Already, a small area of -40C is evident near the North Pole.

A similar real-time evaluation is available for the Southern Hemisphere at

The assessment of the coldest 500 hPa temperatures allows us to assess whether the reported surface increase in Arctic winter temperatures, which has been used as one explanation of why the winter freezing covers less area than the past, also occurs in terms of the area covered by the coldest mid-tropospheric temperatures.

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