Monthly Archives: March 2007

A Seminar On the Importance of Land Surface Processes On the Global Climate System

I thank Jim Angel, the Illinois State Climatologist, for alerting me to this seminar. While most of us cannot attend, the topic is of considerable interest to us.

ANNNOUNCEMENT

The Illinois State Water Survey Presents
Center for Atmospheric Sciences Seminar

A butterfly flaps its wings: The unintended regional and global
consequences of Amazonian deforestation

Peter Snyder
Department of Atmospheric Sciences
University of Illinois at Urbana-Champaign

Tuesday, April 3 2007 2:00 – 3:00 PM
Illinois Room – ISWS Conference Room
Coffee and Cookies at 1:45 PM

ABSTRACT

Although it has been established that the biosphere has an influence on the atmosphere at local and regional scales, there is widespread disagreement over whether the biosphere is capable of influencing the global climate through large-scale changes to the atmospheric general circulation. Numerous studies have already identified the regional climate response to human modification of the landscape through changes to the biophysical exchanges of energy, water, and momentum between the land surface and the atmosphere. However, we still do not understand whether land use and land cover change are capable of influencing remote regions through teleconnection processes. Furthermore, given a specific surface forcing, it is not entirely clear where the response will occur, how strong it will be, or how large a surface forcing is required in order for a climate response to be felt globally. Tropical deforestation is one example of a surface forcing that has the potential to influence the global climate. Several studies have suggested that significant changes to the Northern Hemisphere climate may occur as a result of selective tropical deforestation in the Amazon basin, yet most of these studies have focused on the climate response in the extratropics with little explanation of the mechanisms responsible for propagating the signal out of the tropics. This has led to disagreement over whether these mechanisms are real or are, in fact, artifacts generated by “noise” in climate models.

I will present results from a coupled atmosphere-biosphere model, CCM3-IBIS (Community Climate Model, version 3 – Integrated Biosphere Simulator), to illustrate the potential influence of theoretical land use and land cover change on the global climate by way of atmospheric teleconnections. The results suggest that pan-tropical and Amazonian deforestation can have a strong influence on the Northern Hemisphere general circulation by way of changes to synoptic-scale dynamics and land-atmosphere feedbacks both in the Amazon and in Asia. The result is a large warming across parts of Asia in boreal winter. While theoretical, this approach illustrates the potentially important processes connecting regional land surface changes in the tropics to climate changes in far-removed regions.

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A New Paper Which Demonstrates The Importance of Land Surface Heat Storage Within The Climate System

I want to thank Jos de Laat of the Royal Dutch Meteorological Institute (KNMI) for alerting me to a new peer reviewed paper on land surface heat storage. It is a very important research contribution as it adopts the appropriate unit of Joules to assess climate system heat changes.

The paper is

Stevens M. B., J. E. Smerdon, J. F. González-Rouco, M. Stieglitz, H. Beltrami (2007), Effects of bottom boundary placement on subsurface heat storage: Implications for climate model simulations, Geophys. Res. Lett., 34, L02702, doi:10.1029/2006GL028546.

The abstract reads,

“A one-dimensional soil model is used to estimate the influence of the position of the bottom boundary condition on heat storage calculations in land-surface components of General Circulation Models (GCMs). It is shown that shallow boundary conditions reduce the capacity of the global continental subsurface to store heat by as much as 1.0 × 10**23 Joules during a 110-year simulation with a 10 m bottom boundary. The calculations are relevant for GCM projections that employ land-surface components with shallow bottom boundary conditions, typically ranging between 3 to 10 m. These shallow boundary conditions preclude a large amount of heat from being stored in the terrestrial subsurface, possibly allocating heat to other parts of the simulated climate system. The results show that climate models of any complexity should consider the potential for subsurface heat storage whenever choosing a bottom boundary condition in simulations of future climate change.”

Important excerpts from the paper, as noted by Dr. de Laat include

“Most GCMs have shallow BBCPs [bottom boundary placements]; Figure 3 can serve as a guide to scale results from other models. For any soil model, if the BBCP is at a depth that is too shallow, the amount of energy stored in the ground may be underestimated. As shown in Figure 3, an increase in BBCP from 10 m to 100 m could result in a four- to five-fold increase in heat storage potential. Furthermore, if there is a feedback mechanism involved between land surface and atmosphere, this unabsorbed quantity of heat may partition to other model subsystems. This is potentially a very important issue for climate models since ascertaining the energy balance of the climate system and all its components is a fundamental requirement for proper evaluations of future climatic trends [Shin et al., 2006, and references therein].”

“As the simulation depth in the 1DSM increases, so too does the potential for subsurface heat storage. For example, for a BBCP at a depth of 10 m, the total heat stored in the subsurface (1.9 × 10**8 J) would be less than one-quarter of the asymptotic value (8.8 × 10**8 J). If scaled over the entire continental surface (1.5 × 10**14 m2), 1.0 × 10**23 J, or 75% of the corresponding asymptotic value (1.3 × 10**23 J) would not be stored in the terrestrial subsurface. This heat, absorbed over 110 years, is more than an order of magnitude greater than the heat absorbed by both the whole atmosphere and continental areas in the latter half of the 20th century [Beltrami et al., 2002; Levitus et al., 2005; Huang, 2006; Beltrami et al., 2006a].”

This is yet another example of why an assessment of heat storage changes in units of Joules should be the appropriate global warming and cooling currency (e.g. see), as well as further evidence of the complexity of the climate system which, unfortunately has been inaccurately discussed in the IPCC assessments. A significant consequence of such deeper land heat storage is that the GCM multi-decadal global climate predictions with shallow lower boundaries are overestimating the land surface temperature trends in response to a positive global radiative forcing.

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Did The Oceans Really Cool Between mid-2003 and mid-2005?

Climate Science has reported numerous times on the paper

Lyman, J. M., J. K. Willis, and G. C. Johnson (2006), Recent cooling of the upper ocean,
Geophys. Res. Lett., 33, L18604, doi:10.1029/2006GL027033.

We have been informed today, however, that a correction will be completed soon on this paper in which the recent cooling trend will be removed.

Climate Science will report on this important new development when it is publically available, as well as the implications with respect to the posting

The Net Climate Feedbacks Must Be A Negative Effect On The Global Average Radiative Imbalance If The IPCC Conclusion Of Net Anthropogenic Radiative Forcings Is Correct

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“Some Fresh Air in the Climate Debate” – An Op Ed by Hendrik Tennekes

On March 28, 2007 the #1 newspaper in Amsterdam De Volkskrant published the following op-ed by Hendrick Tennekes. It reads,

“Recently, IPCC, the climate panel of the United Nations, issued a new report. It focuses on the relation between the emission of greenhouse gases and the rise in globally averaged temperatures in the next one hundred years. A few degrees Centigrade are forecast; in all likelihood this must be ascribed to the burning of fossil fuels. The sea level rise expected by IPCC is on the order of four millimeters per year.

Though it would be easy to write an extensive commentary about these predictions, I feel no need to take issue with IPCC on this point. Taking into account that the worldwide supplies of oil and gas are shrinking, and that Mr. Putin has threatened more than once to shut off the supply of natural gas to Europe, I agree it is necessary to pay more attention to energy-saving technology. Energy policy requires a high priority, both nationally and internationally.

But this does not mean that the climate debate is over now. I just mention a few points that bug me. Assuming that the IPCC numbers are reliable, I find the Doomsday picture Al Gore is painting – a six-meter sea level rise, fifteen times the IPCC number – entirely without merit. IPCC would have substantially lessened the acrimony in the climate debate if it had said so explicitly. It would have credited IPCC also if it had taken issue against the pressure exerted on professionals who doubt the majority view. It is unbecoming that American television weather forecasters who express doubts about global warming are likely to lose their jobs. The planned removal of State Climatologists George Taylor (Oregon), David Legates (Delaware), and Patrick Michaels (Virginia) also does not contribute to an atmosphere of unfettered professional discourse.

I protest the tendency to simplify the climate debate to a matter of fossil fuels, greenhouse gases, and a relatively minor global temperature increase. I protest the rude way geologists and astronomers are shoved aside. Whatever the IPCC staff thinks, it is not at all inconceivable that decreasing solar activity will lead to some cooling ten years from now. And if we look at the climate with a geologist’s eye, we see all kinds of changes that have no discernible origin. In the long run we will enter a new ice age, but in the mean time we may encounter all kinds of ups and downs. The climate is always changing; that happened also when there were yet no people on this planet.

I protest vigorously the idea that the climate reacts like a home heating system to a changed setting of the thermostat: just turn the dial, and the desired temperature will soon be reached. We cannot run the climate as we wish. That is fortunate, because a bad season for farmers may be a boon for the tourist industry, deteriorating conditions for French farmers may mean improving conditions for their Polish colleagues, what is good for winter wheat may make things worse for corn, and so on. We are not dealing with a machine, but with Nature herself, and she is not easily mocked.

I want some fresh air in the climate debate, free of the acrimony surrounding the IPCC report. Fortunately there is plenty room for a breath of fresh air if we stop focusing on greenhouse gases to the exclusion of other matters. We obtain that freedom if we decide to think and act not only globally, but primarily locally. My colleague Roger Pielke Sr , professor emeritus of meteorology at Colorado State University and presently senior scientist at the University of Colorado in Boulder, has been investigating the effects of changing agricultural and forestry practices for many years. He doesn’t stop at commiserating, as so many do, the climatic effects of tropical deforestation. He has demonstrated that increasing irrigation leads to enhanced summer precipitation, for example, in Colorado, Kansas, and Oklahoma. He also charted the effects of southward moving orange plantations on Florida’s microclimate and found that the frost risks for the orange crops had moved southward as fast as the plantations themselves. Local climates can change this much by aggressive farming practices.

Another perspective opened by letting some fresh air in is to consider the concrete vulnerability of societies, in particular those in poor countries, to present climate. This is the vulnerability paradigm proposed by Pielke’s son Roger Jr, who is a political scientist at the University of Colorado, and his colleague Daniel Sarewitz of Arizona State University. If the present climate problems of vulnerable regions are addressed forcefully, then 90% of the future problems there have become manageable. Don’t bother to ponder whether or not climate change is responsible for Katrina’s destructive impact, but state boldly that local, regional, and national authorities have ignored the warnings issued by the US Corps of Engineers for some twenty years. In my little lowlands country something similar has happened. Twenty years of warnings by the engineers in the Ministry of Public Works were thoughtlessly laid aside by the Dutch government. It finally woke up when the storm surge of February 1, 1953 claimed nearly two thousand lives. Then it was too late.

Let me summarize. In the climate, much more is at stake than the probable consequences of a slight temperature rise. The dwindling supplies of gas and oil and the direct effects of greenhouse gases get more than sufficient attention from the global community. But next to that there is a wide, only partially explored territory of local and regional vulnerabilities. Due to the incessant emphasis on the global aspects of the climate problem, this territory does not receive the attention it deserves. That is a shame.

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Impacts Of Land Use/Cover Classification Accuracy On Regional Climate – Another Paper That Documents The Major Role Of The Land Surface Within The Climate System

Another paper has appeared which further demonstrates the first order role of land surface processes within the climate system (thanks to Dev Niyogi for letting us know of this paper; subscription required to obtain full paper). The paper is

Ge, J., J. Qi, B. M. Lofgren, N. Moore, N. Torbick, and J. M. Olson (2007), Impacts of land use/cover classification accuracy on regional climate simulations, J. Geophys. Res., 112, D05107, doi:10.1029/2006JD007404.

The abstract reads,

“Land use/cover change has been recognized as a key component in global change. Various land cover data sets, including historically reconstructed, recently observed, and future projected, have been used in numerous climate modeling studies at regional to global scales. However, little attention has been paid to the effect of land cover classification accuracy on climate simulations, though accuracy assessment has become a routine procedure in land cover production community. In this study, we analyzed the behavior of simulated precipitation in the Regional Atmospheric Modeling System (RAMS) over a range of simulated classification accuracies over a 3 month period. This study found that land cover accuracy under 80% had a strong effect on precipitation especially when the land surface had a greater control of the atmosphere. This effect became stronger as the accuracy decreased. As shown in three follow-on experiments, the effect was further influenced by model parameterizations such as convection schemes and interior nudging, which can mitigate the strength of surface boundary forcings. In reality, land cover accuracy rarely obtains the commonly recommended 85% target. Its effect on climate simulations should therefore be considered, especially when historically reconstructed and future projected land covers are employed.”

An excerpt from the paper reads,

“Human activities are transforming the surface of the Earth at an accelerated pace. Such disturbance of the land can affect local, regional, and global climate by changing the energy balance on the Earth’s surface and the chemical composition of the atmosphere [Chase et al., 1999; Houghton et al., 1999; Pielke, 2001]. Over the past decades, land use/cover has been widely recognized as a critical factor mediating socioeconomic, political and cultural behavior and global climate change [International Geosphere-Biosphere Programme (IGBP), 1990; Lambin et al., 1999; Watson et al., 2000]. Numerous attempts have been made to understand past climate changes and to project potential future climate changes by incorporating reconstructed historical land cover changes and projected possible future land cover changes into numerical simulations [Xue, 1997; Pielke et al., 1999; Chase et al., 2000; DeFries et al., 2002; Taylor et al., 2002]. Recent studies have suggested that land use/cover change is a first-order climate effect at the global scale [Feddema et al., 2005].”

The 2007 IPCC Statement for Policymakers clearly chose to minimize the important role of land surface processes as part of the human influence on the climate system.

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Guest Weblog By Syun-Ichi Akasofu – Global Warming And The Little Ice Age

Dr. Syun-Ichi Akasofu has been the Director of the International Arctic Research Center of the University of Alaska Fairbanks since its establishment in 1998. He has been Professor of Geophysics since 1964. Dr. Akasofu has published more than 550 professional journal articles, authored and co-authored 10 books and has been the invited author of many encyclopedia articles. He has collaborated with numerous colleagues nationally and internationally, and has guided nine students to their Ph.D. degrees.

He is certainly well qualified scientifically to present his perspective on climate change. He has completed several articles on this subject; e.g.

Why has “global warmingâ€? become such a passionate subject?
– Let’s not lose our cool –

Is the Earth still recovering from the “Little Ice Ageâ€??
A possible cause of global warming

His contribution as a guest weblog follows:

Global Warming and the Little Ice Age

Many studies of the present global warming focus only on changes during the last 100 years or so, or after 1975 (based on satellite data). By extending records back for 100-200 years (however inaccurate the data may be, compared with satellite data) based on related publications, it has become clear that the present warming research is inadequate. This is because there has been a change of the temperature with an almost constant rate (about +0.5°C/100 years) from about 1800, or even much earlier, to the present. Since the increase began well before the rapid increase of CO2 in about 1940, this warming trend is likely to be a natural change.

One possible cause of the linear increase may be that the Earth is still recovering from the Little Ice Age. World glaciers and sea ice in the Arctic Ocean have been receding since 1800 or earlier; these are not just recent phenomena. It seems to me that most climate researchers are so caught up in the CO2 effect, the Little Ice Age has been all but forgotten.

In addition, multi-decadal oscillations were in a positive phase (~+0.1°C/10 years) during the last 30 years or so of the last century. These trends should be subtracted from the temperature data during the last 100 years.

Thus, there is a possibility that only a fraction of the present warming trend may be attributed to the greenhouse effect resulting from human activities. This conclusion is contrary to the IPCC (2007) Report, which states that “mostâ€? of the present warming (+0.7°C/100 years) is due to the greenhouse effect.

It is urgent that natural changes be correctly identified and removed accurately from the presently ongoing changes in order to find the contribution of the greenhouse effect. Some details are given at: http://www.iarc.uaf.edu/highlights/2007/akasofu_3_07/index.php

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More Background Information On Diagnosing Global Warming and Cooling

The value of using the ocean heat budget to diagnose the radiative imbalance at the top of the atmosphere was originally presented in the seminal paper

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

This was a motivation for the paper

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

In the Ellis et al paper on page 1961, the variation in the annual amplitude variation in the solar radiative forcing of 11.2 Watts per meter squared (due to the Earth’s elliptical orbit around the Sun) provides a perspective on global warming and cooling due to this “purely external driving mechanism”. While this heat imbalance sums to zero in an annual average, there clearly is global warming and cooling within each year. When all of the influences on the global heat budget are considered (see Figure 4), the variation across the year is on the order of 40 Watts per meter squared. This large variation in the value of global radiative imbalance within the year makes the accurate diagnosis of the multi-decadal trends in anthropogenic radiative forcing (the estimated 1.6 Watts per meter squared total net anthropogenic value of 1.6 Watts per meter squared) in Figure SPM-2 of the 2007 IPCC Statement for Policymakers a challenge.

This paper also confirms that dominate role of the oceans in the climate system response to the annual variation in solar insolation. They also express a particular interest in possible interannual variations from the average conditions reported in their paper. With the new ocean observing system (Argo), the plots of the estimated radiative imbalance should be prepared in near-real time on a monthly basis.

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