B43H-01 INVITED
Rates And Patterns Of Historical Land-use Change: Lessons For Modeling The Future
Several recent studies have reconstructed historical changes in global land cover over the last 300 years. These data describe the broad general patterns of human settlement and economic development in different regions of the world. They also lend support to the notion of land-use transitions, from frontier forest clearing, to extensive agriculture, to intensive agriculture, and finally to urbanization and conservation. What lessons can be drawn from a knowledge of these past land-use changes and their drivers? What are their implications for modeling future land-use change? This talk will provide an overview of the major historical land-use changes over the last 300 years and their implications for our ability to model the future.
B43H-02 INVITED
Decision Making in Rangelands: An Integrated Modeling Approach to Resilience and Change
Rangelands comprise approximately 25% of the earth's surface and these landscapes support more than 20 million people and most of the world's charismatic megafauna. Most of the people who live in these regions of the world herd domestic livestock and some do limited cultivation so they are dependent directly on the environment for their livelihoods. But change is rapidly changing the environments upon which these people depend through such factors as population pressures, land use and land tenure changes, climate variability, and policy changes which fragment their resources and thus their ability to earn a living. How can we understand change in this linked human-environment system? The study of complex biophysical and human systems can be greatly assisted by appropriate simulation models that integrate what is known about ecological and human decision-making processes. We have developed an integrated modeling system for Kajiado, Kenya where land use management decisions have implications for economics and the ecosystem. In this paper we look at how land use decisions, that is, livestock movement patterns have implications for societal economics and ecosystem services. Research that focuses on local behavior is important because it is at that level where fundamental decisions are made regarding events like extreme climate and changes such as land tenure policy and it is here where resilience is manifested. The notion that broad recommendation domains can be identified for a broad set of people and large regions coping with change is becoming increasingly hard to trust given the spatial and temporal heterogeneity of the systems we are looking at, and the complexity of the world we now live in. Why is this important? The only way the research community is going to make great progress in attaining objectives that do confer resilience (on social and ecological systems) is through much better targeting ability, a large part of which seem to be intimately entwined with understanding how make decisions are made at the local level. http://www.nrel.colostate.edu/projects/dru/
B43H-03
Modeling Future Land Use, Regional Climate, and Maize Yields in East Africa
The Climate-Land Interactions Project –CLIP— is studying regional climate dynamics coupled to land cover/land use change (LCLUC) in East Africa. Projections of LCLUC in East Africa reflect dramatic shifts in population, socioeconomic drivers, and distributions of agriculture and pastoralism. These shifts in LCLUC in turn are expected to strongly perturb phenology and vegetation cover. Such large-scale trends can influence crop cultivation and maize yields. In addition to LCLUC, climate change due to greenhouse gas concentrations is also expected to influence the growing season and the yields of maize cultivation in the region. Here we present an integrated projection of East Africa's crop-climate system under a future climate state via CCSM and a future land use state via the Land Transformation Model. We join a regional climate model (the Regional Atmospheric Modeling System, RAMS) with the DSSAT-CERES-maize crop model to assess changes in maize yield. The projections are made at current (2000-2009) and future (2050-2059) states, with land use change projections based on estimates of future shifts in demographics and current land use trends. We present differences in temperature and precipitation between current and future states along with associated projections of annual crop yield. These comparisons between the current conditions (Case 1), greenhouse gas effects only (Case 2), LCLUC effects only (Case 3), and the synergistic combined effects (Case 4) will illustrate potential relative impacts of LCLUC versus greenhouse climate change and identify regions of particular sensitivity to these coming changes. We also examine different impacts on the highlands and coasts as well as unexpected results of LCLUC on climate – e.g. does inland moisture transport decline due to increased coastal agriculture? http://clip.msu.edu
B43H-04
Anthropogenic Biomes: A Framework for Earth Science and Ecology in the 21st Century
Humans have fundamentally altered global patterns of biodiversity and ecosystem processes. Surprisingly, existing systems for representing these global patterns, including biome classifications, either ignore humans altogether, or simplify human influence into at most 4 categories. Here we present the first characterization of the terrestrial biomes based on global patterns of sustained direct human interaction with ecosystems. Eighteen "anthropogenic biomes" were identified through empirical analysis of global population, land use and land cover. More than three quarters of Earth's ice-free land showed evidence of alteration by human residence and land use, with less than a quarter remaining as wildlands, supporting just 11% of terrestrial net primary production. Anthropogenic biomes offer a new way forward in developing models and investigations of the terrestrial biosphere that integrate human and ecological systems, going beyond the conventional view of these as a single dimension of human disturbance, impact or domination, and moving towards an operational view of humans as shapers of ecosystem structure and function. This is a critical framework for future efforts to model and mediate anthropogenic changes in the terrestrial biosphere, as most of "nature" may now be considered as being embedded within anthropogenic mosaics of land use and land cover. It is our hope that wide availability of an anthropogenic biome system will encourage a richer view of human/ecosystem interactions across the terrestrial biosphere and that this will in turn lead to improved models and investigations of ecosystem processes and their changes at global and regional scales. http://www.ecotope.org/projects/biomes.htm
B43H-05
Global climate model simulations with a realistic representation of irrigation
Sensitivity studies with global and regional climate models have shown that replacing existing land cover with irrigated land can cause significant changes in climate. To provide a more realistic assessment of irrigation's influence, we performed a series of irrigation experiments with the Community Atmosphere Model (CAM). An irrigation fraction was computed for each grid cell based on FAO irrigation maps, and this fraction of agricultural area was then irrigated in the cell throughout an AMIP simulation (1980-1999). This experiment and a control simulation were performed both at 2-degree and half-degree spatial resolutions, with the latter aimed at resolving land use within heterogeneous areas such as California. Results are presented for changes in temperature, precipitation, humidity, runoff, and other variabiles. In addition, we evaluated whether irrigation reduced the bias of climatologies when compared to observed climate over the AMIP time period. Finally, we investigate the factors leading to regional differences in the response of climate to irrigation.
B43H-06
Estimates of Geographically Explicit Future CO2 Emissions From Land Cover/ Land Use Changes
Land cover and land use change activities, such as deforestation, afforestation, and agriculture management, are important sources of not only CO2, but also non-CO2 GHGs and aerosols. The objective of this paper is to evaluate the potential contribution of future GHGs and reactive GHGs emissions via changes in regional land use-related activities at a 0.5 degree by 0.5 degree resolution. Regional land use is downscaled to the grid cell level based on socioeconomic, biophysical, and biogeochemical factors. Socio-economic factors include population density at the grid zone level. Land sustainability and attainable crop yields, as well as terrain conditions, are biophysical and biogeochemical factors that were also determined at each grid zone level. The productivity of land was determined by the length of growing period (LGP) using the biophysical and biochemical cycles of the Integrated Science Assessment Model (ISAM). Agro-ecological and economic indexes were constructed using historical and current-day cropping practices at the grid zone levels. In the future, the distribution of LGPs may be altered due to changes in carbon, nutrients, and climate. This paper uses two IPCC SRES (A2 and B1) emissions and land use scenarios during the time period 2000-2050 to evaluate the relative importance of land use emissions to future net terrestrial CO2 uptakes.
B43H-07
Coupling of a GCM of Intermediate Complexity and a Dynamic Vegetation Model Including Interactions With Land Use
IMAGE is an ecological-environmental framework that simulates the environmental consequences of human activities worldwide. It represents interactions between society (including land use), the biosphere and the climate system to assess sustainability issues like climate change, food security and human well-being. Currently the climate-carbon-vegetation system is modelled in a rather simple way. For example, IMAGE includes a simple climate model and translates long-term trends in surface temperature to climate changes on the gridlevel using output patterns from state-of-the-art GCMs. IMAGE has been used in many studies and has shown to be very useful, but does not allow investigating more regional aspects of climate change and feedbacks between climate and land cover including land-use change. Therefore, IMAGE has been extended by the GCM of intermediate complexity SPEEDY coupled to the dynamic global vegetation model (DGVM) LPJ. This allows for investigating the "hot spots"in the interactions between vegetation, climate, carbon and land use for different scenarios and to analyze the types of dependencies (linear, discontinuities, tipping points). It requires frequent adaptations of model characteristics and many ensemble members which is not possible with complex GCMs because of computational limitations. Currently, a simple link between SPEEDY/LPJ and IMAGE has been established, in which the IMAGE output of a scenario run in terms of land-use change is used to drive SPEEDY/LPJ. A full coupling in terms of land use change decisions being affected by the output from SPEEDY/LPJ will be established later. The conceptual background will be presented, followed by first results showing that vegetation and climate patterns generated by the coupled SPEEDY/LPJ framework agree reasonably well with observations. In summer SPEEDY/LPJ generate temperature patterns that are in reasonable agreement with observations, also considering the performance of state-of-the-art GCMs of the same resolution. In winter, there are larger deviations between predicted and observed temperature in northern hemisphere climates (Central Asia and eastern Canada).
B43H-08 INVITED
Including Land Use and Land Cover Change in Earth System Models
The Millennium Ecosystem Assessment provided the most recent well-documented global view of recent, rapid land-cover and land-use change. These results coincided with its review of the structure of the major proximate and ultimate drivers of global changes and changes in the provision and sustainability of ecosystem services. This review is now supplemented by the recent findings of the IPCC Fourth Assessment Report, which reinforces previous ideas of regional vulnerability and the importance of carbon cycle feedbacks due to land-cover change. We review these recent findings, and the state of science in modeling the economic choices for land-use and land-cover change that are currently implemented in the Joint Global Change Research Institute's Integrated Assessment Model, the MiniCAM, and make a series of research recommendations for the challenges of incorporating human decision-making and ecological phenomena in the next generation of Earth System Models.