Monthly Archives: April 2009

“Antarctic Ice Increasing” – A Weblog Post By Ed Ring Of Ecoworld

Ed Ring of Ecoworld has posted today (April 30, 2009) an excellent weblog titled “Antarctic Ice Increasing”, which provides some much needed balance in the discussion of climate science. I am correctly quoted in the article;

“Just like last year, to assist in the research for this post I contacted Dr. Roger Pielke Sr., a climatologist at the University of Colorado whose blog http://www.climatesci.org is one of the most balanced forums and respected sources of technical information on global climate anywhere. In response to my inquiry, he wrote the following: ‘The sea ice around the continent is far above average (ref. UIUC). Also, note the colder than average sea surface temperatures around Antarctic (ref. NOAA). If the media is going to discuss the Wilkens Ice Shelf, they should also discuss this other data. The expansion of the sea ice coverage implies a cooling.’”

 

 

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Article In Western Water Law “Wet Winter In Arizona’s High Country Brings Worries About Floods – Not Drought”

There is an informative article in the publication Western Water Law and Policy Reporter by M. Becker titled “Wet Winter In Arizona’s High Country Brings Worries About Floods – Not Drought”.

Excerpts from the excellent article read

“A wet January and February throughout Northen Arizona drained by the Salt and Verde rivers followed a December that was the 11th wettest month in more than a century of recording keeping on the Salt and Verde River watersheds……See “Reservoirs Full to the Brim, More Rain Due,” Payson Roundup, February 17, 2009.”

“The precipitation has left the Salt and Verde Rover reservoirs brimming at about 21 percent above normal. Roosevelt Dam is a t 100 percent capacity. This capacity level means that lake levels are at the highest levels ever.”

“These reservoirs hold enough water to get the Phoenix area through three to five years of drought”.

Climate Science has often discussed the issue of drought in the western United States, and has concluded that the claims of almost perpetual droughts in the coming years is not scientifically robust. Examples of the Climate Science weblogs that discuss this issue include

http://climatesci.org/2008/05/08/when-will-lake-mead-go-dry-a-new-paper-that-uses-multi-decadal-global-models-for-regional-predictions/

Comments on a New Report on Climate Change in Colorado: A Synthesis to Support Water Resources Management and Adaptation for the Colorado Water Conservation Board by Ray et al. 2008

 http://climatesci.org/2008/10/27/new-article-on-the-need-to-move-from-dubious-multi-decadal-regional-climate-predictions-to-the-assessment-of-regional-vulnerabilites/

http://climatesci.org/2008/09/08/dynamical-downscaling-assessment-of-model-system-dependent-retained-and-added-variability-for-two-different-regional-climate-models-by-rockel-et-al/

The wet winter this year in Arizona should be yet another wake-up call to policymakers who are using multi-decadal regional climate predictions, assuming that they have skill, when the real world data indicates otherwise.  The southwest USA has not moved into a perpetual drought due to the addition of carbon dioxide into the atmosphere.

 

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Limits on CO2 Climate Forcing from Recent Temperature Data of Earth: A Guest Weblog by David Douglass and John Christy

Our paper

Limits on CO2 Climate Forcing from Recent Temperature Data of Earth

has just been published in Energy and Environment. (Vol 20, Jan 2009). [Copies may be downloaded from http://www.nsstc.uah.edu/atmos/christy_pubs.html . preprint with figures in color at  http://www.pas.rochester.edu/~douglass/]  

We show in Figure 1 the well established observation that the global atmospheric temperature anomalies of Earth reached a maximum in 1998.

 

This plot shows oscillations that are highly correlated with El Nino/La Nina and volcanic eruptions. There also appears to be a positive temperature trend that could be due to CO2 climate forcing.

We examined this data for evidence of CO2 climate forcing.  We start by assumed that CO2 forcing has the following signature.

1. The climate forcing of CO2 according to the IPCC varies as ln(CO2) which is nearly linear over the range of this data. One would expect that the temperature response to follow this function.

2. The atmospheric CO2 is well mixed and shows a variation with latitude which is less than 4% from pole to pole. Thus one would expect that the latitude variation of the temperature anomalies from CO2 forcing to be also small.

Thus, changes in the temperature anomaly T that are oscillatory, negative or that vary strongly with latitude are inconsistent with CO2 forcing.

The latitude dependence of the UAH data is shown in Figure 2.

 

The anomalies are for NoExtropics, Tropics, SoExtropics and Global. The average trends are 0.28, 0.08, 0.06, and 0.14 K/decade respectively. If  the climate forcing were only from CO2 one would expect from property #2 a small variation with latitude.  However, NoExtropics is 2 times that of the global and 4 times that of the Tropics.  Thus one concludes that the climate forcing in the NoExtropics includes more than CO2 forcing. These non-CO2 effects include: land use [Pielke et al. 2007]; industrialization [McKitrick and Michaels 2007, Kalnay and Cai 2003, DeLaat and Maurellis 2006]; high natural variability, and daily nocturnal effects [Walters et al. 2007].

Thus we look to the tropical anomalies. If one is able to determine an underlying trend in the tropics, then assuming that the latitude variation of the intrinsic CO2 effect is small (CO2 property #2), then the global trend should be close to this value.

Figure 3 shows the tropical UAH data and the nino3.4 time-series. (Results consistent with these were found using RSS microwave temperatures, but evidence also presented here and elsewhere indicates RSS is less robust for trend calculations.)

One sees that the value at the end of the data series is less than at the beginning. However, one should not conclude from this observation that the trend is negative because of the obvious strong correlation between UAH and nino3.4.

The desired underlying trend, the ENSO effect, the volcano effect can all be determined by a multiple regression analysis. The regression analysis yields the underlying trend

            trend = 0.062±0.010 K/decade; R2 = 0.886.                 (1)

 Warming from CO2 forcing
           
How big is the effect from CO2 climate forcing?  From IPCC [2001]

             ΔT (CO2 ) ≈λ* ΔF (CO2 )                                             (2)

             ΔF (CO2 )  ≈ 5.33 ln (C/C0)*

where l is the climate sensitivity parameter whose value is 0.30 ºK/(W m-2) for no-feedback; C is the concentration of CO2, and C0 is a reference value. From the data the mean value of the slope of ln(C(t)/C(t0)) vs. time from 1979 to 2004 is 0.044/decade.

Thus,

                          ΔT (CO2 ) ≈ 0.070  K/decade                     (3)

This estimate is for no-feedback. If there is feedback leading to a gain g, then multiply Eq. 3 by g. The underlying trend  is consistent with CO2 forcing with no-feedback. It is frequently argued that the gain g is larger than 1, perhaps as large as 3 or 4. This possibility requires there to be some other climate forcing of negative sign to cancel the excess. From the results of Chylek [2007], this cancellation cannot come from aerosols. One candidate is the apparent negative feedback associated with changes in cirrus clouds when warmed [Spencer et al. 2007].

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New Paper “Climate Response To Regional Radiative Forcing During The Twentieth Century” By Shindell And Faluvegi 2009

Climate Science has reported on the role of aerosols in the Arctic as a radiative warming effect; e.g. see

New Study On The Role Of Soot Within the Climate In The Higher Latitudes And On “Global Warming”/

New Paper Elevates The Role Of Black Carbon In Global Warming

Arctic Tundra Shrub Invasion And Soot Deposition: Consequences For Spring Snowmelt And Near-surface Air Temperatures.

This includes the study we published

Strack, J., R.A. Pielke Sr., and G. Liston, 2007: Arctic tundra shrub invasion and soot deposition: Consequences for spring snowmelt and near-surface air temperatures. J. Geophys. Res., 112, G04S44, doi:10.1029/2006JG000297

There is a very important new paper that adds significantly to this subject. it is

Drew Shindell & Greg Faluvegi, 2009: Climate response to regional radiative forcing during the twentieth century. Nature Geoscience 2, 294 – 300 (2009) Published online: 22 March 2009 | doi:10.1038/ngeo473.

The abstract reads

“Regional climate change can arise from three different effects: regional changes to the amount of radiative heating that reaches the Earth’s surface, an inhomogeneous response to globally uniform changes in radiative heating and variability without a specific forcing. The relative importance of these effects is not clear, particularly because neither the response to regional forcings nor the regional forcings themselves are well known for the twentieth century. Here we investigate the sensitivity of regional climate to changes in carbon dioxide, black carbon aerosols, sulphate aerosols and ozone in the tropics, mid-latitudes and polar regions, using a coupled ocean–atmosphere model. We find that mid- and high-latitude climate is quite sensitive to the location of the forcing. Using these relationships between forcing and response along with observations of twentieth century climate change, we reconstruct radiative forcing from aerosols in space and time. Our reconstructions broadly agree with historical emissions estimates, and can explain the differences between observed changes in Arctic temperatures and expectations from non-aerosol forcings plus unforced variability. We conclude that decreasing concentrations of sulphate aerosols and increasing concentrations of black carbon have substantially contributed to rapid Arctic warming during the past three decades.”

The conclusion of the paper includes the text

“Our results suggest that aerosols have had a large role in both global and regional climate change during the twentieth century. Both these results and forward modelling indicate that Arctic climate is especially sensitive to Northern Hemisphere short- lived pollutants. Arctic trends may also be related to internal atmosphere-ocean dynamics. Our analysis is consistent with a large role for internal variability, but suggests an even greater impact from aerosol forcing on trends since 1930. A large aerosol contribution to mid-twentieth century Arctic cooling perhaps accounts for the lack of polar amplification in some studies. During 1976-2007, we estimate that aerosols contributed 1.09 +/- 0.81 C to the observed Arctic surface temperature increase of 1.48 +/- 0.28 C. Hence, much of this warming may stem from the unintended consequences of clean-air policies that have greatly decreased sulphate precursor emissions from North America and Europe (reducing the sulphate masking of greenhouse warming) and from large increases in Asian black carbon emissions.”

“Our calculations suggest that black carbon and tropospheric ozone have contributed ~0.5-1.4 C and ~0.2-0.4 C, respectively, to Arctic warming since 1890, making them attractive targets for Arctic warming mitigation. In addition, they respond quickly to emissions controls, and reductions have ancillary benefits including improved human and ecosystem health”.

This new paper further bolsters the conclusion that, as reported on Climate Science (see), that

“Research has shown that the focus on just carbon dioxide as the dominate human climate forcing is too narrow. We have found that natural variations are still quite important, and moreover, the human influence is significant, but it involves a diverse range of first-order climate forcings, including, but not limited to the human input of CO2 (e.g. see NRC, 2005 and Kabat et al, 2004). These other forcings, such as land use change and from atmospheric pollution aerosols, may have a greater effect on our climate than the effects that have been claimed for CO2.”

My perspective on the diversity of human climate forcings beyond the radiative effect of added CO2 is sumarized in

Pielke Sr., Roger A., 2008: A Broader View of the Role of Humans in the Climate System is Required In the Assessment of Costs and Benefits of Effective Climate Policy. Written Testimony for the Subcommittee on Energy and Air Quality of the Committee on Energy and Commerce Hearing “Climate Change: Costs of Inaction” – Honorable Rick Boucher, Chairman. June 26, 2008, Washington, DC., 52 pp. [View PDF of Oral Summary].

 

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A New Article “A New Pathway for Absorbing Aerosols’ Influence On The Interannual Variability By Bollasina and Nigam

The February 2009 issue of the GEWEX Newsletter has quite an interesting and very valuable article entitled

“A New Pathway for Absorbing Aerosols’ Influence on the Interannual Variability of the South Asian Monsoon” by Massimo A. Bollasina and Sumant Nigam Department of Atmospheric and Oceanic Science, University of Maryland, College Park, MD, USA (pages 10-11).

The conclusion of the article reads

“The results described suggest that although anomalously high aerosols are associated with deficient precipitation over India in early spring, internal atmosphere–land-surface feedback actually strengthens the monsoon in subsequent summer months. Land-surface processes, once triggered by anomalous aerosol concentration and induced low cloudiness and precipitation, are important mediators in monsoon evolution and hydroclimate. The finding of the significant role of the land-surface in the realization of the aerosol impact is somewhat novel, as best as we can tell, as only heating of the lower troposphere and solar dimming effects on both and and oceans have hitherto been emphasized. Observations at weekly resolution are currently being analyzed at various lead/lag intervals to identify the sequence of physical processes generating the aerosol influence.”

The authors provide more detail on their excellent study in the paper

Massimo Bollasina, Sumant Nigam, and K.-M. Lau, 2008: Absorbing Aerosols and Summer Monsoon Evolution over South Asia: An Observational Portrayal. Journal of Climate Volume 21, Issue 13 (July 2008) pp. 3221–3239 DOI: 10.1175/2007JCLI2094.1

 The abstract of that paper reads

“The South Asian haze builds up from December to May, is mostly of anthropogenic origin, and absorbs part of the solar radiation. The influence of interannual variations of absorbing aerosols over the Indo- Gangetic Plain in May on the Indian summer monsoon is characterized by means of an observational analysis. Insight into how the aerosol impact is generated is also provided. It is shown that anomalous aerosol loading in late spring leads to remarkable and large-scale variations in the monsoon evolution. Excessive aerosols in May lead to reduced cloud amount and precipitation, increased surface shortwave radiation, and land surface warming. The June (and July) monsoon anomaly associated with excessive May aerosols is of opposite sign over much of the subcontinent (although with a different pattern) with respect to May. The monsoon strengthens in June (and July). The analysis suggests that the significant large-scale aerosol influence on monsoon circulation and hydroclimate is mediated by the heating of the land surface, pursuant to reduced cloudiness and precipitation in May. The finding of the significant role of the land surface in the realization of the aerosol impact is somewhat novel.”

This is yet another research contribution that highlights the role of land use as a first order climate forcing, as well as the linkage between different human climate forcings (in this case aerosols and land use). We summarized a number of these linkages in our paper

Pielke Sr., R.A., J.O. Adegoke, T.N. Chase, C.H. Marshall, T. Matsui, and D. Niyogi, 2007: A new paradigm for assessing the role of agriculture in the climate system and in climate change. Agric. Forest Meteor., Special Issue, 132, 234-254.

 

 

 

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New Paper “Changes In The Asian Monsoon Climate During 1700-1850 Induced By Pre-Industrial Cultivation by Takata et al. 2009

There is an original and very significant new paper in the Proceedings of the National Academy of Sciences which has been accepted. It is

Takata, K., K. Saito, and T. Yasunari, 2009: Changes in the Asian Monsoon Climate During 1700-1850 Induced by Pre-Industrial Cultivation. PNAS,(in press).

The abstract reads

“Pre-industrial changes in the Asian summer monsoon climate from the 1700s to the 1850s were estimated with an Atmospheric General Circulation Model (AGCM) using historical global land cover/use change data reconstructed for the last 300 years. Extended cultivation resulted in a decrease in monsoon rainfall over the Indian subcontinent and southeastern China, and an associated weakening of the Asian summer monsoon circulation. The precipitation decrease in India was marked, and was consistent with the observational changes derived from examining the Himalayan ice-cores for the concurrent period. Between the 1700s and the 1850s, the anthropogenic increases in greenhouse gases and aerosols were still minor; also, no long-term trends in natural climate variations, such as those caused by the ocean, solar activity, or volcanoes, were reported. Thus, we propose that the land cover/use change was the major source of disturbances to the climate during that period. This report will set forward quantitative examination of the actual impacts of land cover/use changes on Asian monsoons, relative to the impact of greenhouse gases and aerosols, viewed in the context of global warming on the interannual, decadal, and centennial time scales.”

As they write in the paper

“Between the 1700s and the 1850s, the major anthropogenic disturbance to the climate in Asian Monsoon region was caused by cultivation. There were no marked trends in the concentrations of greenhouse gases and aerosols between the 1700s and the 1850s”.

This seminal study should put to rest claims that added well-mixed greenhouse gases are the only first order climate forcing. 

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New Paper “A Modified Kain-Fritsch Scheme And Its Application For Simulation Of An Extreme Precipitation Event In Vietnam By Truong Et Al 2009

We have a new paper that has been accepted for publication. It is

Truong, N.M., T.T. Tien, R.A. Pielke Sr., C.L. Castro, and G. Leoncini, 2008: A modified Kain-Fritsch scheme and its application for simulation of an extreme precipitation event in Vietnam. Mon. Wea. Rev, (in press).

The abstract reads

“From 24 to 26 November 2004, an extreme heavy rainfall event occurred in the mountainous provinces of central Vietnam, resulting in severe flooding along local rivers. The Regional Atmospheric Modeling System, version 4.4, is used to simulate this event. In the present study, the convective parameterization scheme includes the original Kain-Fritsch scheme and a modified one where a new diagnostic equation to compute updraft velocity, closure assumption, and trigger function are developed. These modifications take the vertical gradient of the Exner function perturbation into account, with an on-off coefficient to account for the role of the advective terms. According to the event simulations, the simulated precipitation shows that the modified scheme with the new trigger function gives much better results than the original one. Moreover, the interaction between convection and the larger-scale environment is much stronger near the middle troposphere where the return flow associated with lower-level winter monsoon originates. As a result, the modified scheme produces larger and deeper stratiform clouds and leads to a significant amount of resolvable precipitation. On the contrary, the resolvable precipitation is small when the original scheme is used. The improvement in the simulated precipitation is caused by a more explicit physical mechanism of the new trigger function and suggests that the trigger function needs to be developed along with other components of the scheme, such as closure assumption and cloud model, as a whole. The formalistic inclusion of the advective terms in the new equation gives almost no additional improvement of the simulated precipitation.”

This paper illustrates the level of skill possible for predicting this type of societally important weather events, and further documents the major weather threats we face today, irregardless how humans are altering the climate system.

 

 

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