Monthly Archives: February 2009

Meeting Summary “Global Warming And The Next Ice Age” By Dubey Et Al 2008

Climate Science has weblogged about a meeting Global Warming and the Next Ice Age that was held in Santa Fe, New Mexico July 17-21 2006; i.e. see, see, see, and see.

The AMS Bulletin of the American Meterological Society has published a summary of this meeting in its December 2008 issue;

 Manvendra K. Dubey, Charlie S. Zender, Chris K. Folland, and Petr Chylek, 2008: Global Warming and the Next Ice Age. Bulletin of the American Meteorological Society, pp. 1905–1909. DOI: 10.1175/2008BAMS2359.1.

The goal of the meeting was that

“More than 120 scientists from 14 countries with expertise in the observation, theory, and
modeling of climate change met to discuss how Earth’s climate responds to non–greenhouse gas forcings, and how to improve predictions of these responses.”

The BAMS meeting summary starts with the text

“Earth’s climate is a complex dynamical system that is responding to an array of forcings, which include anthropogenic carbon dioxide and aerosols and solar variability. Aeorsol and solar forcings are imperfectly constrained and only monitored by observational systems with limited sensitivity and coverage.”

Among the conclusions of the meeting, as written at the end of the BAMS article is that

“It was determined during this conference that the optimal path to reduce uncertainties and increase precision of climate change forecasts is by bringing in observations to inform, test, and refine climate models. This is particularly important for aerosols and clouds, which are complex and influence the planetary albedo and radiation budget significantly. Progress is being made and the outlook it good since many aerosol-cloud perturbations and processes operate on shorter time scales rendering them measurable. However, this is a daunting task for other longer-term feedbacks such as ocean–ice–atmosphere changes where our community will have to use paleoclimate data or gather longer records to validate climate models, an interaction that our meeting also catalyzed. Observationalists and modelers (Xiao and Li 2007) must play a synergistic role in climate change research to increase the precision of climate forecasts for future energy options.”

A unique aspect of this meeting was that it was inclusive and permitted the spectrum of viewpoints on climate to be presented.  This balance is often lacking in other meetings, as documented recently on Cliamte Science; e.g. see

Protecting The IPCC Turf – There Are No Independent Climate Assessments Of The IPCC WG1 Report Funded And Sanctioned By The NSF, NASA Or The NRC.

We need more such balanced, inclusive conferences as summarized in the 2008 BAMS article.

Comments Off

Filed under Climate Science Meetings

A New Paper “The Impact Of Agricultural Intensification And Irrigation On Land–Atmosphere Interactions And Indian Monsoon Precipitation —A Mesoscale Modeling Perspective by Douglas et al 2009

We have in press another peer reviewed paper that demonstrates the role of land surface processes as a first order climate forcing as well as an integral component of any assessment of climate variability and change [our study complements the peer reviewed paper by Lee et al which was weblogged on Climate Science on January 30 2009].

The paper is

Douglas, E.M., A. Beltrán-Przekurat, D. Niyogi, R.A. Pielke, Sr., and C. J. Vörösmarty, 2009: The impact of agricultural intensification and irrigation on land–atmosphere interactions and Indian monsoon precipitation —A mesoscale modeling perspective, Glob. Planet. Change, doi:10.1016/j.gloplacha.2008.12.007 [see this link also for the paper].

The abstract reads 

“Using the Regional Atmospheric Modeling System (RAMS) we show that agricultural intensification and irrigation can modify the surface moisture and energy distribution, which alters the boundary layer and regional convergence, mesoscale convection, and precipitation patterns over the Indian monsoon region. Four experiments were conducted to simulate a rain event from 16 to 20 July 2002 over the Indian region: (i) a control with Global Land Cover land use and observed Normalized Difference Vegetation Index, (ii) an irrigated crop scenario, (iii) a non-irrigated crop scenario, and (iv) a scenario for potential (natural) vegetation. Results indicate that even under active monsoon conditions, the simulated surface energy and moisture flux over the Indian monsoon region are sensitive to the irrigation intensity and this effect is more pronounced than the impact of land use change from the potential vegetation to the agricultural landscape. When model outputs were averaged over the south Asia model domain, a statistically significant decrease in mean sensible heat flux between the potential vegetation and the irrigated agriculture scenarios of 11.7 W m-2 was found. Changes in latent heat fluxes ranging from -20.6 to +37.2 W m-2 (-26% to +24%) and sensible heat fluxes ranging -87.5 to +4.4 W m-2 (-77% to +8%) fluxes were found when model outputs were averaged over Indian states. Decreases in sensible heat in the states of Punjab (87.5 W m-2 or 77%) and Haryana (65.3 W m-2 or 85%) were found to be statistically significant at the 95% confidence level. Irrigation increased the regional moisture flux which in turn modified the convective available potential energy. This caused a reduction in the surface temperature and led to a modified regional circulation pattern and changes in mesoscale precipitation. These agricultural changes, including irrigation modify the mesoscale convection and rain patterns in the Indian monsoon region. These regional changes in land use need to be considered in improved weather forecasting as well as multi-decadal climate variability and change assessments.”

An excerpt from the Summary and Conclusions reads

“The growth in human population has increased the demand food supplies leading to intensified agriculture worldwide. The consequent changes in agricultural practices can lead to alterations in the landscape via changes in the land-use land-cover including irrigation……Irrigation increased the regional moisture flux which in turn modified the convective available potential energy (CAPE), caused reduction in the surface temperature and led to a modified regional circulation pattern and changes in mesoscale precipitation. It is anticipated that agricultural changes, and irrigation impacts, can modify the regional climate and the mesoscale convection and rain patterns in the Indian monsoon region and need to be considered in multi-decadal climate variability and change assessments.”

Comments Off

Filed under Climate Change Forcings & Feedbacks, Climate Models, Research Papers

Importance Of Land Use Versus Atmospheric Information Verified From Cloud Simulations From The Monteverde Frontier Region of Costa Rica” by Ray et al. 2009

We have another paper accepted for publication which examines the importance of land use and of atmospheric information with respect to mesoscale and regional weather and climate predictions. It is

Ray, D. K., R. A. Pielke Sr., U. S. Nair, R. M. Welch, and R. O. Lawton (2009). Importance of land use versus atmospheric information verified from cloud simulations from a frontier region in Costa Rica, J. Geophys. Res., doi:10.1029/2007JD009565, in press

The abstract reads

“Land-use/land-cover (LULC) change has been recognized as a key component in global climate change and numerous climate modeling studies at regional to global scales document this. The research strategies have invariably been to first conduct baseline simulations of current conditions to evaluate model performance. Then simulation of regional climate with land cover changes (LCC) implemented within the model allows differences with the baseline simulation to be used as evidence of global to regional-scale climate impacts of LCC.

However, even state-of-the-art regional climate models require two datasets to conduct reasonable baseline simulations. These are representative current land cover and atmospheric information over the study region. In frontier and developing areas (where most of the rapid land-use conversion is taking place), these datasets are frequently unavailable and the errors in simulations are either due to inaccurate land cover, insufficient atmospheric information, non-representative model physics, or a combination of one or more of the above. This study shows that in one frontier region, that surrounding the Cordillera de Tilarán of Costa Rica, the accuracy of simulating clouds decreases by 1% to 3% if default model land cover information is used. If the atmospheric datasets used are the ones usually available to researchers (with land cover information held constant), then the model accuracy is reduced by 21% to 25%. Model runs without updated land cover or atmospheric information reduces model accuracy slightly further. Precipitation comparisons also provided similar results.

This study thus shows that the critically important dataset for conducting accurate simulations is not land cover information but atmospheric information. Researchers may similarly get significant increase in the accuracy of their baseline simulations elsewhere by using radiosondes/rawinsondes over their study region. Finally, since atmospheric information is not available for different landscape scenarios, assessments of the relative role of LULC change will have to continue to rely on using the standard atmospheric data set and the acceptance that the use of more detailed atmospheric data to initialize and provide lateral boundary conditions would have reduced the uncertainties in such landscape sensitivity studies.”

An excerpt from the paper reads

“From this study, however, it is quite clear that changes in land cover and atmospheric information will result in changes in simulation accuracy……..With respect to assessing the relative role of land-use change on the climate system, the improved simulation accuracy with better atmospheric structure information has an important implication. Since atmospheric information, of course, is not available for different landscape scenarios, (i.e. simulations are one-way nested regional model integrations in which there is no interaction from the regional to the large scales through the lateral boundaries) assessments of the relative role of LULC change will still have to rely on either using the standard atmospheric data set or on the use of more detailed atmospheric data over the current landscape even though it is affected by the current landscape for initial and lateral boundary conditions. The latter approach will reduce the simulation differences expected in such landscape sensitivity studies since the initial atmospheric conditions with a different landscape would in reality, of course, be different.”

This study is relevant to dynamic regional downscaling from global models, which a technique used to obtain local climate change impact information (see). What is can be concluded from this study is that even with the best land surface information, if the atmospheric information being transmitted into the regional model through lateral boundary conditions is not accurate, the impact assessment will, necessarily, be erroneous. 

Comments Off

Filed under Climate Change Forcings & Feedbacks, Climate Models

An Egregious Example Of Biased News Reporting

I was quite stunned this morning to read the following news articles

“Global warming seen worse than predicted” by Julie Steenhuysen of Reuters

 “Scientists: Pace of Climate Change Exceeds Estimates”By Kari Lydersen of the Washington Post.

These news is also reported at 431 other sites according to a search on google.

These articles are based on statements by Christopher Field, founding director of the Carnegie Institution’s Department of Global Ecology at Stanford University. I have a lot of respect for Dr. Field as an expert on the carbon cycle [I also have worked with him in the past].

However, while he is credentialed in climate science and certainly can have his own opinion, the selection of his statements to highlight in prominent news articles, without presenting counter perspectives by other climate scientists, is a clear example of media bias.

Dr. Fields is reported to have said

“We are basically looking now at a future climate that’s beyond anything we’ve considered seriously in climate model simulations”.

This claim, though, conflicts with real world observations!

For example, Climate Science has recently weblogged on the issue of global warming; see

 Update On A Comparison Of Upper Ocean Heat Content Changes With The GISS Model Predictions.

Since mid-2003, there has been no upper ocean global average warming; an observation which is not consistent with the GISS model predictions over this time period.

The recent and current tropospheric temperature data (e.g. see Figure 7 in this RSS MSU data), also show that the global lower tropospheric temperatures today are no warmer than they were in 2002.

The recent global warming is less than the IPCC models predict, and, even more so, in disagreement with the news articles.  

Since papers and weblogs have documented that the warming is being over-estimated in recent years, and, thus, these sources of information are readily available to the reporters, there is, therefore, no other alternative than these reporters are deliberately selecting a biased perspective to promote a particular viewpoint on climate.  The reporting of this news without presenting counter viewpoints is clearly an example of yellow journalism;

“Journalism that exploits, distorts, or exaggerates the news to create sensations and attract readers.”

When will the news media and others realize that by presenting such biased reports, which are easily refuted by real world data, they are losing their credibility among many in the scientific community as well as with the public.

Comments Off

Filed under Climate Science Misconceptions, Climate Science Reporting

Article By Josh Willis “Is It Me, or Did the Oceans Cool? A Lesson On Global Warming From My Favorite Denier”

There is a candid, honest, and informative article by Josh Willis that appeared in the newsletter U.S. Clivar Variations. It is

Is It Me, or Did the Oceans Cool? A Lesson on Global Warming from my Favorite Denier by Josh K. Willis of the Jet Propulsion Laboratory ofCalifornia Institute of Technology.

It is worth reading. The article chronicles his experience with correcting the error in his orginal analysis, but also in presenting us with an effective summary of the current science and engineering of diagnosing ocean heat content. He presents two informative figures in the article, which are reproduced below

There are two major conclusions that are evident from these figures:

  • In Figure 2, the wide distribution of the profiling floats provides very good spatial coverage of the oceans except for the highest latitudes

and

  • As discussed in Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335, it is the change in ocean heat content that provides the most effective diagnostic of global warming and cooling. Thus unless further checks on the upper ocean measurements find errors, there has been no significant ocean heating since mid-2003. This means that we now have 5 1/2 years without global warming as measured by this climate metric.

 

 

Comments Off

Filed under Climate Change Metrics

Another Example Of The Importance Of Land Management Within The Climate System – A New Paper By Ridgwell Et Al 2009 Entitled “Tackling Regional Climate Change By Leaf Albedo Bio-Geoengineering”

There is an interesting New York Times article by Henry Fountain titled “More-Reflective Crops May Have Cooling Effect” [and thanks to Matei Georgescu for alerting us to it!]. The article states that

“Andy Ridgwell and colleagues at the University of Bristol in England have another idea, one they call bio-geoengineering. Rather than developing infrastructure to help cool the planet, they propose using an existing one: agriculture.

Their calculations, published in Current Biology, suggest that by planting crop varieties that reflect more sunlight, summertime cooling of about 2 degrees Fahrenheit could be obtained across central North America and a wide band of Europe and Asia.”

This NY Times article is based on the paper

Andy Ridgwell1,Joy S. Singarayer,Alistair M. Hetherington andPaul J. Valdes: 2009 “Tackling Regional Climate Change By Leaf Albedo Bio-geoengineering“. Current Biology, Volume 19, Issue 2, 146-150, 15 January 2009

The abstact of this paper reads

 “The likelihood that continuing greenhouse-gas emissions will lead to an unmanageable degree of climate change [1] has stimulated the search for planetary-scale technological solutions for reducing global warming [2] (geoengineering), typically characterized by the necessity for costly new infrastructures and industries [3]. We suggest that the existing global infrastructure associated with arable agriculture can help, given that crop plants exert an important influence over the climatic energy budget [4,5] because of differences in their albedo (solar reflectivity) compared to soils and to natural vegetation [6]. Specifically, we propose a bio-geoengineering approach to mitigate surface warming, in which crop varieties having specific leaf glossiness and/or canopy morphological traits are specifically chosen to maximize solar reflectivity. We quantify this by modifying the canopy albedo of vegetation in prescribed cropland areas in a global-climate model, and thereby estimate the near-term potential for bio-geoengineering to be a summertime cooling of more than 1C throughout much of central North America and midlatitude Eurasia, equivalent to seasonally offsetting approximately one-fifth of regional warming due to doubling of atmospheric CO2[7]. Ultimately, genetic modification of plant leaf waxes or canopy structure could achieve greater temperature reductions, although better characterization of existing intraspecies variability is needed first.”

The conclusion reads

“Increasing canopy albedo of vegetation in designated cropland areas in a global climate model by 20% (0.04) drives a >1C reduction in summertime surface air temperatures in a wide latitudinal band spanning North America and Eurasia. Genetic modification or selective breeding of crop plants for specific leaf-surface properties and canopy structure could provide further mitigation of surface warming. Because the main investment is in research and field trials, the relatively low cost of implementation of crop albedo bio-geoengineering makes it potentially very attractive when compared to the equivalent costs of geoengineering or carbon sequestration. However, there is a clear need for more research into characterizing the variability in albedo that exists between the different variants and strains of common crop plants to underpin any such undertaking. Changes in crop reflectivity must also not significantly
negatively impact on crop yield through excessive reduction in the absorption of photosynthetically active radiation by chloroplasts under nonsaturating light conditions. Overall, bio-geoengineering could fulfill a role as a temporary measure for reducing the severity of agricultural and health impacts of heat waves in the industrialized North, but on a global scale, it has limited effectiveness for the mitigation of future climate change and cannot substitute for CO2 emissions reductions. Furthermore, although a prominent increase in summertime soil moisture in the southern states of the U.S. also occurs, soil moisture changes show no simple spatial relationship to the prescribed albedo changes, illustrating the difficulties in predicting the response of the global climate system to deliberate modification, particularly with respect to rainfall patterns. The potential for significant regional inequity in soil-moisture changes poses important geopolitical questions.”

This is yet another example of the importance of the human management of the landscape within the regional climate system. A summary of this effect, as well as documenting that advertant and inadvertant land management is not a ‘temporary measure” and that this management has significant consequences even on the global scale, was published in the articles

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

Pielke Sr., R.A., G. Marland, R.A. Betts, T.N. Chase, J.L. Eastman, J.O. Niles, D. Niyogi, and S. Running, 2002: The influence of land-use change and landscape dynamics on the climate system- relevance to climate change policy beyond the radiative effect of greenhouse gases. Phil. Trans. A. Special Theme Issue, 360, 1705-1719.

 

Comments Off

Filed under Climate Change Forcings & Feedbacks, Climate Science Reporting, Research Papers

Climatic Effects of 30 Years of Landscape Change over the Greater Phoenix AZ, Region: Part II by Georgescu et al. 2009

Guest Weblog By Matei Georgescu

Previously, the modeled effect of observed (from the early 1970s to the early 2000s) land use/land cover change (LULCC) over one of the most rapidly developing regions in the US, the semi-arid Greater Phoenix [AZ] region, was shown to have an important impact on the surface energy budget and the near-surface atmosphere (e.g., temperature, dewpoint temperature; see).  We address the role of these surface budget changes and subsequent repartitioning of energy on the mesoscale dynamics/thermodynamics of the region, their impact on convective rainfall, and the association with the synoptic scale North American Monsoon (NAM) circulation in a follow-up paper:

Georgescu, M., G. Miguez-Macho, L. T. Steyaert, and C. P. Weaver (2009), Climatic effects of 30 years of landscape change over the Greater Phoenix, Arizona, region: 2. Dynamical and thermodynamical response, J. Geophys. Res., doi:10.1029/2008JD010762, in press.  (subscription required)

Our modeling results show a systematic difference in total accumulated precipitation between the most recent (2001) and least recent (1973) landscape reconstructions: a rainfall enhancement for 2001 relative to the 1973 landscape. We note that while we see this similarity among the “dry” hydrometeorological seasons, the difference pattern for the “wet” seasons does not indicate such an effect on rainfall.

We find that changes in differential heating, resulting from the evolution of the underlying landscape, produce preferentially located mesoscale circulations (evident on most days) which were stronger for the most recent landscape representation (2001) as compared to the oldest (1973).  These enhanced circulations warm and dry the lower planetary boundary layer (PBL) – due to enhanced turbulent heating – and moisten the upper PBL and free atmosphere.  While these circulations are shown to alter the properties of the PBL in all Julys studied (the effect was larger during “dry” Julys as compared with “wet” Julys, and indeed, there was variability among the “dry” hydrometeorological months as well), direct dynamical forcing does not seem to be the explanation for the simulated precipitation enhancement (a signal we only observe during “dry” Julys and in two of the trio of months we investigated) resulting from the landscape’s evolution. 

While the cause of initial triggering of precipitation enhancement remains elusive, we do show that precipitation recycling plays an important role in sustaining and enhancing the initial difference in rainfall between the most recent (2001) and the least recent (1973) landscapes. 

Importantly, this work documents the interplay amongst the continuum of scales investigated [ranging from the turbulence scale (smallest) to the synoptic scale (largest)], and underscores some of the non-linearities and complexities involved in the coupled land-atmosphere system.

Comments Off

Filed under Guest Weblogs