BES Quarterly Meeting – Planning for Renewal – April 16, 2009
Topic: Land Change Scenarios and Locational Choice Modeling
Organizers: Elena Irwin and Mary Cadenasso
(1) What aspects of land use/land cover (LULC) change are the most important from your perspective? What are the drivers? What are the impacts?
The peri-urban fringe I suspect will continue to be the battleground for LULC and for lots of good reasons. No one likes conversion of pristine farmland or forests to suburban tracts (unless you are the developer or the person buying a house in the suburban tract, and then you want it to stop there). The waste and pollution associated with fragmented leap-frog development will mean a continued focus on the dynamic edge. But I want to make sure that the central city and older inner suburbs are not neglected. What is really important to me is how LULC impacts quality of life (livelihood, safety, security, happiness, health). It is also very important to show how LULC creates uneven consequences for city dwellers and to find ways to mitigate or rectify those inequities. Regarding drivers and impacts, I sent Elena a list a few months back that I think is a good synopsis. C. Boone
Changes in impervious surface and a measure of hydrologic connectivity (does water flow continuously to stream or have opportunity to infiltrate before reaching more impervious surface)
o Drivers: development (roads should be a separable category) and mitigation efforts
o Impacts: hydrologic and aquatic living resources degradation – e.g., loss of spawning and nursery habitat for resident and anadromous fish, loss of water quality treatment and quantity moderation
Changes in Forest Cover, with subcategories for forest buffers and wetlands
o Drivers: development, and mitigation efforts (reforestation/afforestation),
o Impacts: forest fragmentation/habitat loss, loss of forest cover = loss of ecosystems services – clean air, water, good hydrology, carbon, etc
Research needs are to support better data (either better products or techniques for measuring) and to link the land use data to resource conditions of concern, like excess nutrients or fish habitat. Social issues are relevant for the patterns of development, the drivers, and who feels the impacts in human health, safety, and welfare. Anne Hairston-Strang and Christine Conn
From my perspective, land cover is the critical variable rather than land use because changes to land cover more directly influences ecosystem processes. I view changes to land use as an aggregated change that includes changes to cover and potentially to human action at that location. The consequences of human actions for ecosystem processes are most likely modulated by characteristics of land cover. Therefore, I view land cover as the most important indicator of potential impact to ecosystem processes.
At finer spatial scales, the change of land cover from pervious to impervious surfaces is critical for many ecological features of the system including heat dissipation, alteration to hydrology and the loss of “natural” or “green” space. These green spaces may be used by a variety of organisms or important for the regulation of ecosystem processes such as nutrient cycling. At coarser scales, the important aspect shifts a bit for me to one of the spatial patterning of the change. Where on the landscape relative to other biogeophysical features such as slope, soil type, and vegetation characteristics is the land use/land cover change occurring? Also, how aggregated or disaggregated is the conversion relative to previously converted land or land yet to be converted?
Economic incentives or disincentives seem to be important drivers. This is all balled up for me with policies and levels of decision making. The choice of the individual is constrained by personal economics as well as economics and policy that drive higher levels of decision making by businesses, institutions and governments. “Choices” at all levels are constrained to a certain extent by biogeophysical features such as slope. Engineering strategies often allow development to skirt those constraints. On the other hand, biogeophysical features may provide opportunities such as ridgelines that offer views of surrounding landscapes making them more profitable for development.
Impacts are too numerous to consider and would be different for each characteristic of concern. Obviously there are impacts to air, water, health and how people spend their time and resources. Also important are impacts that may constrain future scenarios or available options. Mary Cadenasso
The pattern of land development—i.e., land converted from agriculture or a natural state to urban land use—in and around urban areas is a critical aspect of land use/land cover change. This form of development has led to major increases in per capita land consumption and in low density urban land use. In 1950, the conterminous United States had less than 1% of land at urban densities (more than one house per acre) and about 5% at exurban densities (between 1 and 40 acres per house); by 2000, these densities had grown to nearly 2% and 25% respectively (Brown et al. 2005).
Understanding the human behaviors and decision making processes that underlie land development is critical, as is an understanding of the ways in which individuals respond to policies that influence land use and location decisions. Land use patterns are the result of many, autonomous and heterogeneous individuals making location and land use decisions. What are the factors (land markets, policies, location, amenities, neighborhood quality) that influence individual location and land use decisions? How do these decisions vary across individuals and what sources of heterogeneity—e.g., income, race, education—matter the most? How do individuals’ location and land use decisions influence each other, e.g., how do changes in a neighborhood and the landscape around someone influence their decision to relocate? Looking at this from a political economy viewpoint, what influences policy makers? How do societal preferences influence what policy makers do or don’t do? What determines political pressure? These are not questions that I as an economist am equipped to answer, but they are critical questions.
A key question is: What are the connections between “inner urban” and “outer urban” changes? The City of Baltimore lost substantial population in the 1950s onward due to people moving out of the city and into the Baltimore suburbs. Where did people move from/to and why? How do these jurisdictions compete for good growth or interact in other ways? How has the loss of population in the City influenced the overall “health” or “sustainability” of the region? Elena Irwin
In thinking about vulnerability analysis, the most important aspects of land use/land cover change are those which result in higher levels of population exposure, reduce abilities to withstand exposure to a hazard or stress, and those which may diminish abilities to recover and capabilities to adapt to changing conditions. Usually, US environmental justice research investigates equity among groups and whether there are disproportionate, adverse impacts on low income and/or minority populations. Answering this question from an environmental justice perspective becomes more complicated if we consider the multiple normative standards of procedural and distributional justice, e.g. Rawlsian ideas of arranging inequalities so they maximize the benefit to the least well off, or utilitarian concepts focused on the greatest happiness for the greatest number.
The drivers of these processes are very diverse. In thinking about the intersection of vulnerability, climate change, and environmental justice, examples include:
• gentrification of coastal areas at risk to flooding and sea level rise;
• increases in impervious surfaces combined with factors such as poor housing quality, lack of social services, and neighborhood safety concerns could change the pattern of vulnerability and environmental justice concerns related to heat waves; and,
• land-use/cover changes that alter nutrient cycling and result in greater nutrient burdens on the Chesapeake Bay and shift risks and costs to other groups.
These examples only address the first-order impacts of potential climate changes. Other issues that involve complex linkages are much more difficult to anticipate. For instance, the factors driving the land cover changes could differ by parcel, neighborhood, and region within the city. Uneven investment in land use/land cover changes designed to mitigate environmental hazards, such as flood protection or development of green spaces, and uneven enforcement of regulations are potential driving forces of environmental justice concerns.
The draft white paper Larry and I have started from the earlier meeting offers some other ideas related to climate change and public or environmental disease and pest threats.
The impacts are typically measured by changes in exposure (number of people, property values, infrastructure at risk) to a particular hazard or stress. If the event occurs, measures of mortality, morbidity, emergency room visits, numbers of buildings damaged, presidential natural disaster declaration, claims against the National Flood Insurance Program, and public and private insurance claims are all standard measures. Issues of job loss, business failure, mental health consequences and increased levels of domestic abuse are widely acknowledged but less often measured. Kirsten Dow
(2) What does sustainability or resilience mean to you? How are these terms best defined, represented, modeled, operationalized in the context of cities and metropolitan regions?
A brief definition of sustainability is the simultaneous consideration of environmental, social, and economic variables in all our actions. I don’t like the way that sustainability has shifted emphasis from the original conceptions of sustainable development, which put poverty reduction, human health and well-being as the central priority. Increasingly the social component is an afterthought. I also believe strongly that sustainability should be normative. It should not be about “keeping going” but finding a better way forward, one that includes concepts of justice and fairness. There are a variety of sustainability indicators that municipalities have developed. These are a beginning. But I think starting with a few, directly measurable variables would get cities moving in the right direction. If I had to pick a handful they would be: 1. percent living in poverty; 2. violent crime rate; 3. number of EPA non-attainment days; 4. racial/ethnic/income segregation index; 5. Emergency room visits for respiratory diseases; 6. a water quality measure (leave that for my ecology colleagues); 7. high-school graduation rate. C. Boone
Ability of an ecosystem to remain functional and to recover after a disturbance or while environmental factors are changing – for example, an ecological network of hubs and corridors (Green Infrastructure) provide habitat refugia and migratory corridors that are important for allowing species to adapt and move in response to climate change.
CONNECTIVITY is a key element of sustainability and resiliency. Look at context for metrics that build understanding of connectivity and context. Watershed resiliency can relate structure to function; watersheds can continue to have higher function if they are structured in the right way – all riparian zones and floodplains forested – large blocks of forest in upland areas – good stormwater control – this refers to creating resilient ecosystems for extreme flood and drought events anticipated now and getting more intense via climate change. Anne Hairston-Strang and Christine Conn
Sustainability and resilience are similar in meaning for me though there is a slight and important difference. Sustainability is the ability of a system to maintain processes, functions, diversity, and productivity into the future with minimal effect on the environment. Resilience is the capacity of a system to absorb a disturbance and reorganize while undergoing change so as to retain essentially the same identity, function and feedbacks. The nuanced differences between the two definitions may be that sustainability emphasizes lack of change to system structure in the face of use or extraction whereas resilience emphasizes dynamics and adaptability of the system in face of changing process both internal and external to the target system. For both sustainability and resilience it is often helpful to be more specific than simply to ask whether the system is sustainable or resilient. Specifics such as sustainable for what or for whom, etc.
These concepts are extremely difficult to represent, model or operationalize. They require an acceptance, if not an understanding, of change across multiple spatial and temporal scales. The changes are complex and affect and are affected by physical and social patterns and processes. This makes sustainability and resilience not only difficult to understand and study but also to regulate and requires a flexible management approach. Mary Cadenasso
Sustainability is concerned with some notion of sharing scarce resources across generations in some reasonable or equitable manner. Resilience is concerned with how resistant a particular “state” is given to external changes or shocks to the system. The “state” could be defined in terms of economic (e.g., growing, declining region) or social (e.g., segregated neighborhoods) or a type of land use pattern, e.g., sprawl. It could be a desirable state (healthy region) or an undesirable state (declining region). For example, the suburbs may be growing relative to the city, but how resilient is this growth to an economic shock (downturn in the economy, hike in gas prices) or other shocks (e.g., from policy or change in environmental conditions)? Resilience certainly has something to do with how well off a community is – with vibrant neighborhoods, good public services, etc. a neighborhood is clearly much more resilient than one without these resources.
Sustainability could be either a static or dynamic concept. Resilience is a dynamic concept. The two are related. For example, certain economic or social states in which the system is in, or the system is tending towards over time, can be more or less sustainable. There are many different possible states, some more likely than others. Suppose we identify a sustainable path for the metropolitan area in terms of the amount of land development and its pattern over the next several decades. How does this compare to where the region is now? How resilient is our current state? What sorts of changes (policies, regulations, incentives) may be needed to guide the system to the desired sustainable state? What are the costs and benefits of the different policy options (i.e., how costly is implementing the policies that would kick the system into a more sustainable state? What are the chances of success? What are the benefits if the policies are implemented? What are the consequences of maintaining the current state?)
All of these questions raise basic questions about how we can best evaluate sustainability and resilience. What are the factors/features of the Baltimore region that make it more or less sustainable and resilient? What factors should be counted and how should they be “added up”? The notion of ecosystem services is useful in this regard: ecosystems produce a variety of services that benefit people (at the most basic level, human life is dependent on these services). How are these services valued by people, e.g., what are the benefits that accrue to individuals, communities as a result of these services? Elena Irwin
Many times sustainability and resilience are defined as properties of systems, natural, social, or coupled human environment. In those cases, they refer to the ability of a system to either continue functioning over the long term with no specification of the variability, hazards are stresses or to maintain functioning following a perturbation or stress. From a perspective of vulnerability and environmental justice, I think it is necessary to look at sustainability and resilience with respect to marginal groups. To my knowledge, these marginal groups – poor, low income working people, elderly, minorities – are not typically identified as important in the modeling of systems, but circumstances resulting in disproportionate harm to any of them would be unjust.
With respect to next-generation of BES work, if we are going to approach sustainability and resilience in systems, I think it would be wise to include infrastructure systems. For example, the design of storm water systems is critical to the management of flooding in Baltimore. Is it adequate to meet potential future variability in precipitation and storm surges? Damage to infrastructure systems from natural hazards can have long-lasting and far-reaching social and economic consequences (e.g. New Orleans and Katrina; Flooding in Iowa 2008; California earthquakes). Being prepared to do immediate and long-tern studies of how resilience and adaptation occur following major climate-related events would provide a very rare and valuable data set. Kirsten Dow
(3) What are the biggest challenges that cities and metropolitan regions will face in the next 10, 20, 30 years?
One of the biggest challenges will be how to retrofit and redesign existing cities to be more sustainable. We cannot escape to the suburbs to solve the problems of the city, as Henry Ford once declared. Cities represent huge amounts of fixed capital (housing, other buildings, infrastructure) and human (and place) resources that in many cases is being underused. At some point, perhaps already passed, there will be renewed and growing interest in the old cores. It may be driven by potential return on investment, rising energy costs, demographic shifts (ageing population stranded in the suburbs), yearning for sense of place, or a host of other factors. Brownfields and abandoned houses cannot go on forever. Municipalities stand to gain huge efficiencies in redeveloping existing urban spaces rather than plowing under fields for new suburban growth. A related challenge will be to ensure that central cities can provide safe environments, excellent schools, and neighborhoods that are meaningful and welcoming. C. Boone
The biggest challenges will be the multiplicity of challenges. How issues of crime, economy, transit-oriented development, response to catastrophic events, failing urban infrastructure can all be dealt with simultaneously. Are there better decision paths for this that could support long-term environmental improvement that would not be funded on its own?
The climate change adaptation efforts may be a framework that makes us look at issues more interdependently, but it is still very difficult to implement them in a coordinated fashion with the multitude of players. Another approach may be principles of/building incentives for redevelopment, to avoid further sprawl and address the large existing environmental problems that new environmental regulations seldom address. The challenge for all cities is to recreate the urban environment – add more trees, gardens, open recreational places, trails, jobs, good schools, etc. Diversify the American dream – not the big house in the country, but the elegant, spacious urban penthouse or condominium that is safe and accessible to music, culture, good food, outdoor opportunities. Anne Hairston-Strang and Christine Conn
One of the biggest challenges is planning for or managing a constantly changing system. The changes are happening within the system and are reactions or consequences of actions within the system, but there are also changes occurring at spatial and temporal scales coarser than the system that have to be accounted for. In addition, there is little certainty of the changes at the level of detail often sought to establish policies or programs. A large challenge may be to build regulatory structures that can accommodate changes across multiple characteristics, and spatial and temporal scales and do so in a socially equitable way. Establishing acceptable risk which cuts across physical and social concerns will be a challenge.
An additional challenge is retrofitting cities or dealing with the constraints and opportunities established by past events or decisions. Mary Cadenasso
Rising energy costs: urban regions will have to contend with rising energy costs and face questions about what the “least cost” ways are to reduce high energy consumption. This will require evaluating any number of different energy saving options in terms of the costs (what does it take in terms of capital, government investment to implement, what is the opportunity cost) and benefits (likely savings in the future).
Carbon emissions: Related to energy issues, cities are major sources of carbon. What impacts will federal policies that seek to reduce carbon emissions have on metropolitan areas?
Climate change: Others will be much more articulate than I on this topic. It is certainly an important challenge facing cities.
Intermetropolitan growth: The Baltimore region will continue to compete with other metro regions for the desirable growth (firms that bring jobs and that stimulate economic growth, high skilled workers). Baltimore is at a disadvantage relative to other metro regions (regional climate, older manufacturing city, poverty of central city). How will these factors and other factors shape this dynamic in the future? This has a lot to do with the evolution of other metro areas as well. Baltimore has a strong neighbor in Washington D.C. and has benefited from the outward growth of this metro area. How will this evolve in the future? Lang and Nelson (2007) discuss their predictions in terms of emergence of “megapolitan areas” in the U.S.—large regions that encompass more than one large city typically. They argue that economic interdependence extends beyond a single metro region and thus the future of urban management depends on understanding and managing the growth of these megapolitan areas. Baltimore is located with the area they call the Chesapeake megapolitan area, which includes Washington DC and Richmond VA as well.
Intrametropolitan growth and decline: The process of household sorting implies that regions will become more, not less, segregated over time. This arises from preferences that people have over wanting to be around people like them, regulatory constraints and policies that have fostered this, and also from feedbacks that reinforce growth of prosperous neighborhoods and decline of poorer neighborhoods. Like most metro areas, many areas of Baltimore are relatively segregated. How will these patterns evolve in the future? What are the implications for the overall sustainability of the region? How is inner urban change dependent on outer change? And how does inner impact outer urban change (and vice versa)? This could be a useful way to characterize issues of intrametropolitan growth, decline and equity. Also, the notion of “favored quarter”—i.e., the subregion within a metro where a disproportionate share of the growth flows—could be a useful. Elena Irwin
This is a hard question that involves some value judgments and assumptions about the pace of science as I understand it. With that disclaimer, let’s call these speculations shared among friends.
Cities and metropolitan regions will continue to face a wide variety of compelling social priorities and goals. Updating infrastructure and regulating land-use/cover will take place in the context of strong social and budgetary competition. Therefore, in the area of environmental management, I believe that developing robust, credible, legitimate models of decision-making under climate change uncertainty will be an important near-term 10-15 year challenge. The transition from environmental management strategies which are scientifically and legally justified based on an assumption of stationary of environmental processes across time to something based on dynamics and a different standard of evidence and proof will be a tremendous societal challenge in the US. The rapid pace of scientific advance around climate change issues will add to this challenge. Cities and metropolitan areas will be waiting on the state, federal, and perhaps international bodies for guidance, precedence, and rules. My rationale for identifying this issue among the biggest challenges includes: the likely degree of social controversy; the cross-scale institutional complexity in developing acceptable approaches to dealing with high uncertainty and high decisions stakes problems (see Ravetz and Funtowitz on post-normal science). I expect this issue will be prominent in land use planning efforts and controversies related to climate adaptation.
This is just my back of the envelope calculation, but over the 20 to 30 year time frame, I expect that some key uncertainties about climate change threats will be better characterized on a regional level if not reduced. If that is right, levels of uncertainty and decisions stakes around some urban environmental management issues be within a range that allow for the use of more familiar engineering and expert judgment practices for dealing with uncertainty that will facilitate more action on adaptation. Kirsten Dow
(4) What are the relevant policies (existing and potential) that are needed to address current and future challenges?
o Clean Water Act:
Total Maximum Daily Load limits for streams and Bay- existing and under development (nutrients, sediment, biological, bacterial, mercury….)
Municipal Separate Storm Sewer System Permits (MS4)- existing and increasingly detailed
Antidegradation (Tier II Waters)- partly located not yet regulated
o Clean Air Act:
Air Quality State Implementation Plans- Ozone, others
Maryland Climate Action Plan
o Maryland Planning Requirements
Water Resources Element
Land Protection, Park, and Recreation Plans
o Large blocks of forest should be considered critical habitat and have greater levels of protection,
o Impervious surface fees should be developed,
o Ecosystem markets should be developed (may require governmental regulation) to develop high quality mitigation banks for forests (FIDS), habitat, wetlands, etc…..
Research can help improve the effectiveness of actions and investments of public funding that will be required to be spent over the next decade to address existing problems.
The research need is to develop metrics that can better support workable land use planning, regulation, and markets. Where and how much reduction of impervious surface, stormwater retrofits, and increase in forest cover will make a difference to nutrient reduction or aquatic health? Neither enforcement nor ecosystem markets work well unless metrics are clear and meaningful. Anne Hairston-Strang and Christine Conn
Having no expertise in this area, I make these suggestions in the spirit of dialog. I think we need to continue moving along the path of regional planning and management. Perhaps the “boundaries” of systems need to be multiple, depending on what is being planned or regulated for. The multiple boundaries can be drawn to coincide with the spatial or temporal scale of the anticipated dynamic (e.g. flooding) or to coincide with the structural features or extents (e.g. commuting distances). I’m suggesting fluid boundaries that shift depending on the issue. Because the future challenges are also fluid, policies and programs that are flexible and can incorporate learning from past efforts would seem to be key. This is different from being open to admitting failure but rather recognizing that all decisions or actions are embedded within a specific context that will shift, requiring a reassessment of the original decisions and actions and a willingness to change course as new lessons or insights are gained.
On a general level, we need policies that will change individuals’ behaviors and actions in ways that lead to improvements in sustainability and the resilience of sustainable states (and likewise, decreases in the resilience of unsustainable states). So in order to answer this question effectively, we need to know: (1) how are current or hypothetical changes in policy likely to change individual choices? How will different people respond differently and why? (2) how will the metrics by which improvements are measures (sustainability, ecosystem services, distribution of resources, resilience of the system) change as a cumulative result of individual responses to policy? (3) What are the costs of the human impacts on ecosystem services? What are the costs of various policies aimed at altering behaviors?
More specifically, policies should be targeted to central city, suburbs, exurbs and the social/economic/ political role that each play. Also, we need policies to coordinate across these different areas of the metro region to incorporate the interdependencies among them. For example, central cities should foster creativity and innovation; investments are needed to prevent to onset of decay. Also, it would be useful to better understand the right timing of investments in central city neighborhoods, e.g., what is the optimal time to invest in revitalizing a dying neighborhood , e.g., in terms of tearing down vacant structures and investing in new or renovated housing that can attract new residents—this has to do with understanding the potential demand for this kind of redevelopment. Suburbs house the majority of metro residences and provide the majority of the metro jobs and thus have most of the “assets” of the metro. While they are semi-autonomous from central cities, their well-being is also dependent on the well-being of the entire metro, which is determined by the central city and exurbs as well as suburbs. Exurbs contain many of the ecological assets of the metro, e.g., forested areas that provide a sink for carbon. However, they also generate nutrients that contribute to water quality problems. Policies should be designed to encourage exurbs to invest in the metro’s ecological resources and the rural landscape.
Brown DG, Johnson KM, Loveland TR, Theobald DM. 2005. Rural land use trends in the contemporaneous United States 1950-2000. Ecological Applications 15(6): 1851-1863.
Land, R, Nelson AC. 2007. Beyond the Metroplex: Examining Commuter Patterns at the “Megapolitan” Scale. Lincoln Institute for Land Policy Working Paper WP07RL1. Elena Irwin
This is another hard, interesting question and I am sorry I will miss the discussion of it. Reasonable people disagree about many aspects of what represents needed policy for climate change. I think there is increasing broad support for efforts directed to building adaptive capacity or social learning across agencies and organizations at different levels to assure that needed new information on climate-related issues is collected, the capacity exists to interpret the information, and flexibility to act on information. Some would advocate a strong precautionary principle approach and make efforts to reduce GHG emissions. Others may interpret that precautionary approach as calling for what is termed a “no regrets strategy,” or focusing on efforts that reduce current risks and will have long-term positive consequences. One can imagine several land-use/ land cover strategies that would meet this criterion. Several participants in adaptation processes have pointed out that climate change efforts will need to be “mainstreamed” into other policy agendas. For instance, decreasing the urban heat island effect within the city would support energy and economic efficiency as well as broader sustainability agendas. Kirsten Dow