Understanding Multiple Environmental Stresses Report of a Workshop (2007) / Chapter Skim
Currently Skimming:
Appendix D Extended Speaker Abstracts
Appendix D Extended Speaker Abstracts
Pages 59-138
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 59... ...
What stands in our way of providing this information? THE NATURE OF THE PROBLEM The driving forces that alter environmental quality and integrity are widely recognized, involving primarily weather and climate, patterns of land use and 1Presented in the order given during the workshop.
|
From page 60... ...
Second, a decade of research on greenhouse gas emissions, ozone depletion, and deforestation has clarified many critical unanswered questions. However, the last decade of effort has also revealed a number of challenges, most notably the challenge of creating integrated global observational capabilities and the computational and scientific limitations inherent in creating a truly integrated, global, coupled system modeling capability suitable for assessing impacts and adaptations.
|
From page 61... ...
, transmission dynamics, and population vulnerabilities severely limited our ability to make robust conclusions on how climate change might influence the distribution and occurrence of many infectious diseases in the future. ADDRESSING SOCIETAL NEEDS The need for society to enhance economic vitality, while maintaining environmental quality and limiting threats to property and life, should drive the environmental research and operational enterprise.
|
From page 62... ...
The demonstration of fiscal efficiency and improved capability and resulting benefit are likely to create a significant additional impetus for developing national and global integrated observing systems.
|
From page 63... ...
Hence, a regional focus is empowered by process studies that are directly tied to answering specific questions designed to assess the impacts of specific human perturbations, to assess advantages and risks, and to enhance economic and societal well-being.
|
From page 64... ...
Global weather and climate models provide the strongest physical foundation for more comprehensive predictive capability. The numerical models that underpin this type of forecast are increasingly becoming the framework for the addition of new numerical formulations designed to predict air quality, the water balance for river forecast models, and a host of other variables, including the migration of forests under climate change conditions.
|
From page 65... ...
An emphasis on a region-specific predictive capability will drive the development of new understanding and new suites of comprehensive interactive high-resolution models that focus on addressing societal needs. A key objective is to bring a demanding level of discipline to "forecasting" in a broad arena of environmental issues.
|
From page 66... ...
In general, western North America has seen significant warming over the last 100 years, particularly in the last couple of decades. It is notable that the recent period of unprecedented population increase in the western United States coincided with one of the wettest periods on record.
|
From page 67... ...
MECHANISMS OF DROUGHT VARIABILITY Great strides have been made recently with respect to understanding the proximal cause of drought in North America. We have long known that drought in the southwestern United States (e.g., 1950s and the recent drought)
|
From page 68... ...
ANTHROPOGENIC VERSUS NATURAL DROUGHT INFLUENCES The IPCC (TAR and a recent CLIVAR-PAGES-IPCC workshop convened by Overpeck and Trenberth) concluded that anthropogenic forcing will likely increase the probability of drought in central and western North America.
|
From page 69... ...
Dealing with drought requires the ability to understand regional climate variability over all seasons and to eventually be able to deliver reliable seasonal to interannual climate outlooks. At present, advances are limited by modeling regional-scale processes, and this limitation is in turn related by the lack of good regional-scale climate monitoring.
|
From page 70... ...
Nearly every concept of drought involves a water budget (water supply versus water demand)
|
From page 71... ...
Expressing this somewhat differently, an adequate definition or framework for conceptualizing drought ought to work equally well in Death Valley and the Olympic Mountains, in Greenland or Kentucky or Panama or Kihei or Aconcagua. Biological systems in all those places must address water supply and demand.
|
From page 72... ...
This water crosses a variety of legal and political boundaries, necessitating a variety of agreements, compacts, and understandings. There are great differences regionally between rain-dominated and more humid environments such as in the eastern United States and the snowdominated and very arid environments found in the western United States.
|
From page 73... ...
. Water quantity and timing affect water quality.
|
From page 74... ...
What we really have is a large number of probability distributions (and some of them with heavy tails, such as precipitation) interacting in many ways, with nonzero odds of occasionally rather spectacular outcomes.
|
From page 75... ...
The temporal variation of demand is not zero, however. In addition, population growth, at whatever rate, can, for example, negate assumptions about the stasis of a system of interest.
|
From page 76... ...
To help create a "worst case" scenario, the study in the early 1990s of severe and sustained drought on the Colorado River initiated the dry period with the lowest observed runoff years in succession. Furthermore, the sequencing of different facets of climate can have great consequences, such as a particular moisture regime (wet or dry)
|
From page 77... ...
Thus, even though it is difficult, we should learn to work and think in this mode as much as we can. In particular, we should be thinking in terms of the probability distributions of our confidence in our observational database, and in the descriptions of how we model how the system evolves from one state to the next.
|
From page 78... ...
:1143–1147. Kelly T. Redmond is regional climatologist and deputy director for the western Regional Climate Center located at the desert Research Institute in Reno, Nevada.
|
From page 79... ...
Berra The western United States was built with, and is highly dependent on, water captured from mountain snowpacks that may be hundreds or even thousands of miles away from population centers and agriculture. The reservoirs built to meet the needs of agriculture, power generation, municipal water supply, and a variety of other uses were conceived, and in some cases built, nearly 100 years ago when populations were scarce, industry demand for power was in its infancy, and endangered species legislation did not exist.
|
From page 80... ...
In comparison, individual dry years interspersed among wet years are tolerable. "These decadal oscillations also have implications for water supply forecasting.
|
From page 81... ...
as a predictive variable to index the effects of soil moisture are also vulnerable to this effect. The causes of the current triple alignment are unknown." SEASONALITY OF SNOWPACK AND DROUGHT IN THE WEST AND RECENT EVENTS Recent publications by Mote (2005)
|
From page 82... ...
What will convince users that this can be done? DATA AVAILABILITY AND REQUIREMENTS FOR MONITORING DROUGHT, CLIMATE, AND WATER SUPPLY The entire world has been transformed by the Internet.
|
From page 83... ...
There is also a need to integrate climate forecasts with hydrological models to account for climate variability. This will be a challenge since the user community needs to understand the relationship of uncertainty between the climate and hydrological forecasts.
|
From page 84... ...
) in Portland, Oregon, where he is responsible for the production and distribution of water supply forecasts for the western United States and management of the NRCS National Climate Program.
|
From page 85... ...
What is missing, however, is a whole human-environment system approach to defining, monitoring, and measuring the frequency and intensity of droughts that takes into account underlying meteorological, hydrological, ecological, and sociopolitical processes. For purposes of discussion it is reasonable to assume that droughts are ultimately triggered by scarcity of expected natural water supply, whether by precipitation deficiency, change in timing of snowmelt, inadequate groundwater recharge, or other forms of water shortage caused by climate variability.
|
From page 86... ...
(2004) , who examined the vulnerability of Indian agriculture to climate variability and a small set of global stressors to determine the effects of being "double exposed." However, common sense suggests that rapid changes in one or more stressors that outstrip existing capacity to adapt to water shortage must, ipso facto, increase the frequency of dry events that become droughts.
|
From page 87... ...
Improved understanding of how multiple stresses interact, both with themselves and climate variability, to influence vulnerability to water shortage; 2. Improved understanding of how adaptive capacity is influenced by multiple stresses; 3.
|
From page 88... ...
dr. Easterling's research interests include the potential for agriculture in developed and developing countries to adapt to climate variability and change; the role of scale in understanding the vulnerability of complex systems; how land use change may influence the uptake and release of carbon in the terrestrial biosphere; the use of experimental long-term climate forecasts to assist decision making under conditions of uncertainty; and the development of methodologies for detecting the impacts of observed 0th-century climate change on natural and managed ecosystems.
|
From page 89... ...
A recent drought beginning around the new millennium impacted the southwestern United States and was the most severe since that of the 1950s. Mortality of several species was observed throughout the Southwest.
|
From page 90... ...
The arrow indicates the time of historical observations of extensive tree mortality (from Allen and Breshears, 1998)
|
From page 91... ...
Drought-induced tree mortality might be exacerbated under higher temperatures. The recent drought in the southwestern United States that triggered regional-scale die-off of piñon pine across the Southwest was not as dry as the previous regional drought of the 1950s (Breshears et al., 2005; Figure 4)
|
From page 92... ...
and the recent drought (2000-2003)
|
From page 93... ...
Because global change is projected to yield droughts under warmer conditions -- referred to as global-change-type drought -- the die-off from the recent drought may be a harbinger of vegetation response to future global-change-type drought (Breshears et al., 2005)
|
From page 94... ...
; rates of soil erosion following the 1950s drought were and remain high. An ability to predict tree mortality, associated ecosystem responses, and effects on the carbon budget and on other ecosystem goods and services should be a high priority for future research (Breshears and Allen, 2002; Millennium Ecosystem Assessment, 2005)
|
From page 95... ...
His research focuses on gradients of vegetation ranging from grassland through forest, vegetation dynamics, including drought-induced die-off, ecological-hydrological dynamics (ecohydrology) , wind and water erosion, soil carbon measurement technology, and applications addressing land use, contaminant risks, and global change.
|
From page 96... ...
comprehensive regional development. Studies of the first-order impacts of climate on each of these elements in the western United States indicate that vulnerability exists in the areas of storage and consumptive depletions versus renewable supply.
|
From page 97... ...
In this presentation we explore the above questions in one western basin, the Colorado, in which all of the above issues are exemplified. CASE STUDY: THE COLORADO RIVER BASIN The Colorado River supplies much of the water needs of seven U.S.
|
From page 98... ...
, known to have occurred in the West over the past 1,000 years, is as yet untested but may be so in the very near future. While recent modeling studies project up to an 18 percent decrease in runoff in the basin under climate change scenarios, just the continuation of drought over the next year will likely induce crisis conditions.
|
From page 99... ...
Crisis conditions can be said to be reached when focusing events occur concurrently with awareness of a finite time necessary for response. As mentioned above, for many basins in the West the normal situation is critical, and relatively small environmental changes can exceed social thresholds of acceptability and reliability.
|
From page 100... ...
social vulnerability and responses to environmental variations; and () the role and use of research-based information in natural resources policy and decision making in the western United States, latin America, and the Caribbean.
|
From page 101... ...
As the impacts of multiple stressors acting simultaneously on forest production are determined, their roles in amplifying or damping regional disparities are being elucidated. Toward these ends we have improved our Terrestrial Ecosystem Model and Atmospheric Chemistry Models to facilitate their interaction.
|
From page 102... ...
1. INFLUENCE OF CLIMATE AND AIR POLLUTION ON ECOSYSTEM CARBON FLUXES Several environmental factors influence carbon sequestration in natural terrestrial ecosystems, including climate variability and change, atmospheric carbon dioxide concentrations, ozone pollution, and atmospheric nitrogen deposition.
|
From page 103... ...
3. CLIMATIC AND NUTRIENT IMPACTS ON NITROUS OXIDE EMISSIONS Natural terrestrial fluxes of N2O from soils are important contributors to the global budget of this greenhouse gas.
|
From page 104... ...
Since soil carbon and temperature are predicted to change in the future, the importance of including the feedbacks to climate forcing involving changing natural emissions of N2O is evident. Ronald G. Prinn is tEPCO Professor of Atmospheric Chemistry, director of the Center for global Change Science, and co-director of the Joint Program on the Science and Policy of global Change at the Massachusetts Institute of technology.
|
From page 105... ...
(Fung et al., 2005) show that carbon sink strengths are inversely related to the rate of fossil fuel emissions, so that carbon storage capacities of the land and oceans decrease and climate warming accelerates with faster CO2 emissions (Figure 1)
|
From page 106... ...
near-cancellation between large regional changes in the hydrological and eco notice the Legend text is different in this version system responses. MODEL DESCRIPTION The physical climate core of the coupled carbon-climate model is a modified version of National Center for Atmospheric Research CSM1.4, which consists of atmosphere, land, ocean, and ice components that are coupled via a flux coupler.
|
From page 107... ...
. The control simulation compares reasonably well against observations for key annual mean and seasonal carbon cycle metrics; regional biases in coupled model physics, however, propagate clearly into biogeochemical error patterns.
|
From page 108... ...
A series of experiments with the coupled carbon-climate model shows that carbon sink strengths are inversely related to the rate of fossil fuel emissions, so that carbon storage capacities of the land and oceans decrease and climate warming accelerates with faster CO2 emissions. Furthermore, there is a positive feedback between the carbon and climate systems, so that climate warming acts to increase the airborne fraction of anthropogenic CO2 and amplify the climate change itself.
|
From page 109... ...
He received his Ph.d. in chemical oceanography from the MIt/woods Hole Oceanographic Institution Joint Program.
|
From page 110... ...
For example, some BVOCs used as signaling compounds are present in the atmosphere at extremely low concentrations and have a negligible impact on the atmosphere. RESPONSE TO CHANGES IN ATMOSPHERIC CHEMICAL COMPOSITION Isoprene emission rates are sensitive to atmospheric trace gas levels.
|
From page 111... ...
This may at least partly explain the surprisingly large seasonal variations in isoprene emissions that have been observed in tropical rainforests, which are the dominant global source of isoprene emission (Guenther et al., 1999)
|
From page 112... ...
In addition, many of the fast-growing tree plantation species (e.g, poplar, eucalyptus, oil palm, rubber tree) have extremely high isoprene emissions (Guenther et al., 2000)
|
From page 113... ...
dr. guenther's research interests include phytogeography and biogeochemistry; biosphere-atmosphere interactions; developing and applying trace gas and aerosol flux measurement techniques; understanding biological, chemical, and physical controls of trace gas fluxes; numerical modeling of chemical exchange between terrestrial ecosystems and the atmosphere; impact of biogenic emissions; and ecosystem uptake and fire emissions on atmospheric chemistry and sustainability.
|
From page 114... ...
. The desire to produce large ensemble simulations is driven by our interest in understanding the phenomenon of global environmental change as one of risk management.
|
From page 115... ...
A description of the EPPA component and the IGSM and freely available reports and reprints are on the Joint Program on the Science and Policy of Global Change website, http://web.mit.edu/globalchange/www/. Here, I would report very briefly some results from our program on each of the three sets of interactions above, to illustrate how modeling the complexity of the system leads to different results than one might otherwise expect.
|
From page 116... ...
Obviously, agriculture is also a sector sensitive to environmental change, and so that interaction among agricultural policies and the natural environment itself is essential. INTERACTIONS BETWEEN THE ECONOMY AND CHANGING TECHNOLOGY A description of the global economy embodied in a computable general equilibrium model such as our Emissions Prediction and Policy Analysis (EPPA)
|
From page 117... ...
Gas prices have since risen dramatically, and this result would now surprise no one, but the only hope of escaping whatever the current mindset with regard to prices is to try to represent underlying fundamentals of demand and resource availability. We have further explored the value of carbon sequestration in oceans, recognizing that ultimately the carbon will end up in the ocean anyway, so that it was properly investigated as "temporary storage" (McFarland et al., 2004)
|
From page 118... ...
INTERACTIONS BETWEEN THE ECONOMY AND THE PHYSICAL-ECOLOGICAL EARTH SYSTEM The grand statement of the problem of interaction of the economy and the physical-ecological earth system is the formal statement of the global warming potential index issue, extended beyond the conventional greenhouse gases to other pollutants and beyond warming to the direct or other effects of substances of concern (Reilly and Richards, 1993; Reilly et al., 2003)
|
From page 119... ...
. We have considered this starting from a relatively complete description of shared generating processes and well-articulated model of the complexity of atmospheric chemistry to show that the 100-year GWPs undervalue methane abatement substantially (Reilly et al., 1999)
|
From page 120... ...
Abandonment of land, or reduced intensity of use, would mean increased carbon uptake, while expansion of intensified use would likely lead to release of carbon and other greenhouse gases. We expect important interactions with mitigation options, in particular biomass energy that competes for land and is similarly affected by environmental change.
|
From page 121... ...
2006. Economic benefits of air pollution regulation in the USA: An integrated approach.
|
From page 122... ...
MIT Joint Program for the Science and Policy of Global Change Report No.
|
From page 123... ...
Even more remarkable was that this increase in production occurred in the face of multiple environmental and social stresses on the food system, including widespread climate variability -- prolonged droughts, severe floods, and heat waves -- and likely the early stages of climate change, pest and pathogen outbreaks, loss of genetic diversity in agroecosystems, desertification and land degradation, water scarcity, war, epidemics, increasing income divides between rich and poor, government mismanagement, and global population growth, to name a few. But the news is not all good as there have been notable regional failures and there are reasons for concern looking into the future.
|
From page 124... ...
Agricultural stressors in sub-Saharan Africa operating at the global scale include climate change and widening agricultural trade deficits. Tropical cropping systems have been shown to be vulnerable to even the slightest increase in temperatures because, for most of the major food crops being grown there, mean maximum temperatures are already at the high end of effective photosynthetic temperatures.
|
From page 125... ...
Agricultural stressors in sub-Saharan Africa operating at regional to local scales include a number of social and environmental challenges. Food production across most of Africa has not kept up with rapid population growth.
|
From page 126... ...
dr. Easterling's research interests include the potential for agriculture in developed and developing countries to adapt to climate variability and change; the role of scale in understanding the vulnerability of complex systems; how land use change may influence the uptake and release of carbon in the terrestrial biosphere; the use of experimental long-term climate forecasts to assist decision making under conditions of uncertainty; and the development of methodologies for detecting the impacts of observed 0th-century climate change on natural and managed ecosystems.
|
From page 127... ...
2. some regions and sectors, especially from the developing world, are more vulnerable to impacts such as climate variability and change than others.
|
From page 128... ...
Isn't it a challenge to develop an integrated perspective to understand the pathways through which socioeconomic, institutional, and environmental processes influence livelihoods, economic activities, urban life, migration, and other realms where adaptive capacity takes place in urban areas? RELEVANCE OF SCALE Scale is important in diverse and not yet fully explored ways when assessing the socioeconomic impacts of changes in atmospheric composition and dynamics.
|
From page 129... ...
• Third, temporal scale is a critical determinant of the capacity of urban systems to adapt to environmental changes. The history of the city -- path dependency -- will determine the diversity and complexity of its population's current and future adaptive capacity.
|
From page 130... ...
2. Try to evaluate the risk of specific adverse outcomes for that unit when confronted with a set of stresses (e.g., climate variability and change, new patterns of foreign direct investment and of industrial location, and structural adjustment programs)
|
From page 131... ...
It pays attention to the social, economic, institutional, and environmental dimensions of adaptation strategies by those agents; it explores how those dimensions interact at different scales. This tool can offer insights to design policies aimed at both enhancing adaptation to the impacts of atmospheric changes and reshaping the socioeconomic impacts of existing urban development pathways.
|
From page 132... ...
. As already mentioned in this paper the first task we are confronted with is to understand within an integrated perspective the pathways through which institutions together with other socioeconomic and environmental processes influence livelihoods, economic activities, urban life, migration, and other realms where adaptive capacity takes place in cities.
|
From page 133... ...
dr. Romero, a sociologist by training, has two doctoral degrees, one in regional development from the Autonomous Metropolitan University and one in agricultural sciences from the University of Bonn, germany.
|
From page 134... ...
The critical point here is that a particular stress, or particular combination of stresses, does not map to a particular economic impact. Between a stress and an impact there are typically human-modified environments, technological systems, and socioeconomic institutions and capabilities whose states and hence responses to stresses depend on both preceding stresses and human decisions to recognize, develop, and protect environmental qualities, technological capacities, and institutional capabilities.
|
From page 135... ...
It was much more difficult to be prepared for and to respond to the combination of stresses known as the "dust bowl" during the Great Depression because the social system was already highly stressed by a dysfunctional economy. No doubt environmental stresses during World Wars I and II also resulted in greater hardship because social system resources were devoted to the wars.
|
From page 136... ...
But to the extent that some of the ways economists derive values flow from an informed public expressing choices, most ecosystem services, especially under conditions of stress, are highly undervalued because people are less aware of the importance of the services than they should be. Richard B. Norgaard is a professor in the Energy and Resources Program at the University of California, Berkeley.
|
From page 137... ...
per year each to the Upper and Lower Colorado River Basins, stipulates that Upper Basin states cannot deplete the flow at Lees Ferry by more than 75 MAF over a period of 10 consecutive years and mandates a moving 10-year average release of 8.23 MAF/year from Lake Powell into the Lower Basin. In the case of D2M variability, 100 years may not be long enough to evaluate stationary assumptions in water resource planning, and we are forced to rely on tree-ring reconstructions of precipitation and streamflow.
|
From page 138... ...
geological Survey and adjunct professor in the departments of geoscience and geography at the University of Arizona. the focus of his research is ecosystem and watershed responses to climate variability on different temporal and spatial scales.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.