Focus 4 - Themes
Tuesday, 21 December 2010 02:14
To address the goals of Focus 4, six topical Themes have been developed:
Theme: Land use and cover
Climate modelers increasingly focus on processes governing changes in the land surface and their coupling to the atmosphere. Thus, there is a growing need for past land use/cover records at global- to continental/regional-scales (e.g., Dearing et al., 2006b; Denman et al., 2007). The major goal of this Theme is to produce land-cover records based on fossil pollen records for the last 11.5 kyr. These reconstructions will be produced at global and continental-regional scale for the entire Holocene in various formats relevant for modelers: curves and trends (site curves, regional syntheses), figures (absolute numbers in percentage cover, biomass, plant functional types, biomes), maps, databases, open vs. forested land, the extent and nature of permanent agriculture, and the extent of grazing. Land-cover reconstructions are also needed to understand and model terrestrial processes, like soil erosion, the direct focus of other PHAROS Themes and WGs.
Working groups
> HITE (Human Impacts on Terrestrial Ecosystems)
> LIMPACS (Human Impacts on Lake Ecosystems)
> LUCIFS (Land Use and Climate Impacts on Fluvial Systems)
Theme: Land Carbon
The carbon cycle lies at the heart of Earth System Science, providing the key contribution to climatic-environmental changes by the redistribution of carbon between terrestrial, oceanic and atmospheric systems. Quantifying carbon fluxes, sources, sinks and stores, and understanding the nature of interactions and feedbacks are essential to climate change research and carbon management. However, the temporal patterns of the major carbon fluxes and their consequences for carbon stores are poorly understood at timescales greater than a few years. This Theme, therefore, provides the historical perspective to these issues, complementing the work of international programs like the Global Carbon Project. The focus is on reconstruction of decadal-millennial carbon dynamics in anthropogenic and pre-anthropogenic systems, long-term changes in carbon stores, particularly through burial in lakes (Kortelainen et al., 2004; Downing et al., 2008) and terrestrial sediments, and spatial syntheses at regional to global scales. The Theme will overlap with Water, Soil/sediment and Land use/cover Themes.
Working groups
> HITE (Human Impacts on Terrestrial Ecosystems)
> LIMPACS (Human Impacts on Lake Ecosystems)
> LUCIFS (Land Use and Climate Impacts on Fluvial Systems)
> IHOPE (Integrated History of People on Earth)
Theme: Biodiversity
The 2005 Millennium Ecosystem Assessment (MEA) recently highlighted critical gaps in our knowledge of biodiversity, for example our understanding of:
- responses of ecosystems to changes in the availability of nutrients and carbon dioxide.
- non-linear changes and structural and dynamic characteristics of ecosystems that lead to thresholds and irreversible biodiversity changes.
- the nature of interactions among drivers of changes in biodiversity at regional scales.
The MEA argues that such information is essential in order to design interventions that intervention procedures that maximize positive impacts on biodiversity. This Theme will focus on the compilation of long-term ecological records at a range of spatial and temporal scales in order to complement the use of existing shorter-term observational records identified by the DIVERSITAS program. Specifically, it will aim to synthesize long-term records that can provide information on: drivers of biodiversity change; determination of baselines and natural ecosystem variability; biodiversity thresholds and resilience; migrations, invasions and extinctions; conservation of cultural landscapes; and wilderness conservation. The Theme will also address the need to improve our recognition of biological remains in natural archives and the need for fundamental work on representativity and congruence to improve interpretation of fossil records.
Working groups
> HITE (Human Impacts on Terrestrial Ecosystems)
> LIMPACS (Human Impacts on Lake Ecosystems)
> LUCIFS (Land Use and Climate Impacts on Fluvial Systems)
> IHOPE (Integrated History of People on Earth
Theme: Water
The quality and quantity of water resources increasingly impose constraints on human societies and ecosystem health in most regions of the Earth. This is particularly so in regions where intense catchment change has altered the hydrological balance and reduced the quality of water supplies and wetlands, and where past and projected climate change shifts the availability of surface water for consumptive and ecosystem needs. Studies of changes in past water quality and quantities have been essential in identifying the trajectory of change and establishing the range of natural variation that existed prior to intense human modifications of catchments, notably through studies of lake acidification and eutrophication. Such approaches have the capacity to quantify natural baseline conditions, identify drivers and rates of past change and to assess the degree of departure from baseline on a broad range of contexts (Bennion and Battarbee, 2007). Through integration with land surface, climate and watershed change the Water Theme will compile and integrate records to gauge 1) the sensitivity or resilience of waterways to catchment development, 2) the points of initiation and trajectories of change that are detrimental to sustainable societal development, 3) the interactions between climate, surface cover and stability changes and aquatic ecosystems over time, and 4) through dynamic models, generate and test scenarios of future water resource availability and condition and the future state of aquatic ecosystems.
Working groups
> HITE (Human Impacts on Terrestrial Ecosystems)
> LIMPACS (Human Impacts on Lake Ecosystems)
> LUCIFS (Land Use and Climate Impacts on Fluvial Systems)
> IHOPE (Integrated History of People on Earth)
Theme: Soil and sediment
Sediment archives (alluvial, colluvial, limnic) provide records of changing soil erosion and the transport/deposition of sediment by fluvial processes. The degree of soil erosion and the extent and volume of sedimentary deposits provide information on the nature and timing of past human impacts, and the impact of environmental variability (particularly climate) on human society (e.g., Brown, 2002; Dearing and Jones, 2003; Gregory et al., 2006; Wasson, 1994). This Theme will integrate soil/sediment records to provide spatially distributed patterns through time and across different regions. The results may be used for interpreting past levels of landscape disturbance, past human-environment interactions, describing trajectories of soil/sediment movements up to the present, defining baselines, reconstructing past sediment budgets, and developing and validating process models. Through interpretation of catchment behavior (hydrological and sediment cycles) within the LUCIFS WG, this Theme will make an important contribution to other PHAROS Themes, PAGES Foci (e.g., Focus 2), IHOPE and the Global Land Project.
Working groups
> HITE (Human Impacts on Terrestrial Ecosystems)
> LIMPACS (Human Impacts on Lake Ecosystems)
> LUCIFS (Land Use and Climate Impacts on Fluvial Systems)
> IHOPE (Integrated History of People on Earth)
Theme: Regional integration
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| Regional Climate Change Index (RCCI) over 26 land regions of the World calculated from 20 coupled Atmospheric-Ocean General Circulation Models and 3 IPCC emission scenarios (A1B, A2, B1). The RCCI is a comparative index that identifies the regions most responsive to climate change (Modified from Giorgi, 2006). |
There is a need to understand how society and the environment have evolved over multi-decadal timescales to create modern landscapes. This can be achieved through integrating instrument, document, paleoenvironmental and archaeology records within regions to produce ‘socio-environmental profiles’. Such profiles are especially important to the development of policies and strategies in regions where successful management of key environmental processes, ecological services and their interaction is critical, for example, within natural wildernesses, biodiversity hotspots, climate change hotspots or regions projected to be particularly vulnerable to combinations of stressors.
This Theme will initially integrate past evidence for environmental processes and ecological services for selected regions that are projected by the IPCC (Fig. 2.23) and others (e.g., Giorgi, 2006) to be climate change “hotspots”. It will compile and integrate records in order to:
1) Identify drivers of change,
2) Track socio-environmental trajectories,
3) Establish levels of modern resilience and vulnerability,
4) Provide the basis for the development and validation of dynamic models for scenario production.
The Regional Integration Theme will develop links to other PAGES Foci (in particular Focus 2), the Global Land Project (GLP) and IHOPE.
Aims
Promote and provide new integrations of historical information at regional scales in order to provide a stronger basis for developing strategies for sustainable management and adaptation to global environmental change.
> Visit the Regional Integration Theme webpage
Working groups
> HITE (Human Impacts on Terrestrial Ecosystems)
> LIMPACS (Human Impacts on Lake Ecosystems) Promote and provide new integrations of historical information at regional scales in order to provide a stronger basis for developing strategies for sustainable management and adaptation to global environmental change.
> LUCIFS (Land Use and Climate Impacts on Fluvial Systems)
> IHOPE (Integrated History of People on Earth)
References
Bennion, H. and Battarbee, R., 2007: The European Union Water Framework Directive: opportunities for palaeolimnology, Journal of Paleolimnology, 38: 285-295.
Brown, A.G., 2002: Learning from the past: palaeohydrology and palaeoecology, Freshwater Biology, 47: 817–829.
Dearing, J.A. and Jones, R.T., 2003: Coupling temporal and spatial dimensions of global sediment flux through lake and marine sediment records, Global and Planetary Change, 39: 147-168.
Dearing, J.A., Battarbee, R.W., Dikau, R., Larocque, I. and Oldfield, F., 2006b: Human-environment interactions: towards synthesis and simulation, Regional Environmental Change, 6: 1-16. DOI: 10.1007/s10113-005-0012-7
Denman, K.L. et al., 2007 : Couplings between changes in the climate system and biogeochemistry. In: Solomon, S. et al. (Eds) Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge: 499-587.
Downing, J.A., Cole, J.J., Middelburg, J.J., Striegl, R.G., Duarte, C.M., Kortelainen, P., Prairie, Y.T. and Laube, K.A., 2008: Sediment organic carbon burial in agriculturally eutrophic impoundments over the last century, Global Biogeochemical Cycles, 22: GB1018, doi:10.1029/2006GB002854
Giorgi, F., 2006: Climate change hot-spots, Geophysical Research Letters, 33: L08707. Doi:10.1029/2006GL025734.
Gregory, K.J. et al., 2006: Past hydrological events and global change, Hydrological Processes, 20: 199-204.
Kortelainen, P., Pajunen, H., Rantakari, M. and Saarnisto, M., 2004: A large carbon pool and small sink in boreal Holocene lake sediments, Global Change Biology, 10: 1648–1653
Wasson, R.J., 1994: Living with the past: uses of history for understanding landscape change and degradation, Land Degradation and Rehabilitation, 5: 79-87.
