B32A-01 INVITED 10:20h
A SOLAS challenge: How can we test test feedback loops involving air-sea exchange?
It is now well accepted that the Earth System links biological and physical processes in the water, on land, and in the air, creating countless feedback loops and dependencies that are at best difficult to quantify. One example of interest to SOLAS scientists is the suspension and long-range transport of dust from Asia, which may or may not interact with acidic air pollutants, that may increase the biological availability of iron, thereby increasing primary productivity in parts of the Pacific. This could increase DMS emissions and modify the radiative impact of Pacific clouds, affecting the climate and the hydrological system that limits the amount of dust lofted each year. Air-sea exchange is central to many such feedbacks: Variations in productivity in upwelling waters off Peru probably change DMS emissions and modify the stratocumulus clouds that blanket that region, thereby feeding back to productivity. The disparate time and space scales of the controlling processes make it difficult to observationally constrain such systems without the use of multi-year time-series and intensive multiplatform process studies. Unfortunately, much of the infrastructure for funding Earth science is poorly suited for supporting multidisciplinary research. For example, NSF's program managers are organized into disciplines and sub-disciplines, and rely on disciplinary reviewer communities that are protective of their slices of the funding pie. It is easy to find authors of strong, innovative, cross-disciplinary (yet unsuccessful) proposals who say they'll never try it again, because there is so little institutional support for interfacial research. Facility issues also complicate multidisciplinary projects, since there are usually several allocating groups that don't want to commit their ships, airplanes, or towers until the other groups have done so. The result is that there are very few examples of major interdisciplinary projects, even though IGBP core programs have articulated the need for them. Achieving IGBP's goals requires new observational and organizational strategies. Some relatively modest changes in the ways that facilities and grants are awarded could make it possible to do multidisciplinary experiments of the type described in the SOLAS Science Plan and Implementation Strategy.
B32A-02 10:35h
Earth Systems, Fish and Fishers: Global Dependence and a Not-so-Quiet Revolution
Paleoceanographic records of fish abundance have demonstrated the existence of cycles of abundance in many fish stocks, such as sockeye salmon, sardines, and anchovies. Some of these cycles have frequencies that coincide with oscillations in the global climate and in the earth rotational velocity, suggesting the interlinked nature of the Earth System and its functioning. However, the development of large industrial fisheries, particularly in the second half of the 20th century, has overwhelmed many of these low frequency cycles of natural marine productivity. Selective overexploitation of the sea has severely damaged some fisheries resources and caused large-scale ecosystem disruptions. The result has been imbalanced marine ecosystems which are more vulnerable to collapse during low phases of their production cycles and a crisis in the survival of small fishing communities. Humans rely on the sea and its products to meet our needs for protein, linking the dynamics of the earth with issues of global food security. How to synchronize and balance the dynamics of the Earth system and the human needs for food, rather than compound their effects, is a major management challenge. This contribution will provide examples of this challenge, such as the post-cod scenario in Newfoundland ecosystems and human communities, and the dynamics of salmon and First Nations cultures in the NE Pacific. We will illustrate some of the approaches being followed, from basin-scale ecosystem modeling through complex adaptive systems theory to integrated cross-disciplinary team studies of social-ecological systems (e.g., Coasts Under Stress http://www.coastsunderstress.ca/), in the search for global sustainability of fish and fishers.
B32A-03 10:50h
LOICZ: Coastal Change and the Anthropocene
Delivery of materials from greatly modified catchments to rapidly changing global coastal basins has been a major focus of the IGBP LOICZ Core Project. Analysis of about 200 nutrient budgets produced significant regression equations to predict inorganic nutrient loads using catchment population density and basin scaled runoff. These relationships were applied to a coastal environmental dataset with global coverage at 0.5-degree resolution to provide initial estimates of nutrient loading at earth system scale. An estimated 74 thousand megamoles of dissolved inorganic phosphorus and 1,350 thousand megamoles of dissolved inorganic nitrogen make up the annual nutrient load reaching the global coastal zone. About 70% of the total load comes from catchments with low to intermediate yields (1 and 3 kmol DIP per sq. km.), indicating the significant role of less polluted systems in global material transport. LOICZ II hopes to expand the nutrient and coastal environmental datasets in coverage and in data density and to incorporate quantitative and qualitative indicators of anthropogenic drivers in its ongoing study of human-coast interactions. In addition, it aims to incorporate remotely sensed data on land use and coastal ocean color with socioeconomic indicators to allow for integrated modelling. Its current science plan wishes to address measures of vulnerability to human and natural perturbations with the hope of informing policy to create sustainable coastal scenarios at local to global scales. This presentation is made on behalf of the LOICZ Project and acknowledges portions derived from Smith et al. (2003).
B32A-04 11:05h
Global iron connections
The environmental conditions at the surface of the Earth are determined by the interactions of the physical, chemical, biological and human processes that transform and transport materials and energy. This is the Earth system - a highly complex entity characterized by multiple non-linear responses and thresholds, with linkages between often disparate components. The interaction with climate of atmospheric transport of soil material, dust, and the global biogeochemical cycling of iron is a prime example of the interconnected nature of the Earth system. Here I use the role of global iron connections to highlight some of the new challenges faced and the need to take a more defocussed and holistic view of the response of climate to perturbation.
B32A-05 11:20h
Carbon-Climate Feedbacks in the NCAR Community Climate System Model
Climate change influences carbon inventories on land and in the oceans, and they in turn determine the CO2 abundance in the atmosphere. A new generation of climate models predicts the co-evolution of climate and CO2 in the atmosphere. We present results from several experiments of the NCAR carbon-climate model, where fossil fuel emission are specified and vegetation and ocean carbon processes interact with the climate and circulation. In a scenario where fossil fuel emissions, if 100% airborne, would increase the atmospheric CO2 abundance by ~900 ppmv in 2010, a surprising result is that there is only a small difference (~30 ppmv) in the globally-averaged CO2 concentration in the atmosphere whether the land and ocean carbon cycle in the model experiences the control or the evolving climate and circulation. Discussion will focus on how such a model could be assessed, and what research is needed to advance the modeling.
B32A-06 11:35h
A Three-Dimensional Coupled Climate-Carbon Simulation of a Business-As-Usual Carbon Emissions Pathway to Year 2300
Eventual emissions from recoverable fossil-fuel carbon resources, if unabated, may exceed 5000 GtC over several centuries, yet most studies of climate change have focused on doubled-CO2 or century scale experiments. Here, we investigate climate change and carbon budget out to year 2300 assuming that humans will continue the current trend using fossil fuels and releasing CO2 to the atmosphere. We use emissions and non-CO2-GHG concentrations from the SRES A2 scenario for the period 2000 to 2100; this trajectory is extended with a smooth logistic curve that eventually releases 5000 GtC to the atmosphere as CO2, with non-CO2-GHG concentration fixed at year 2100 values. Our simulations are performed in a fully-coupled three-dimensional climate and carbon cycle model, the INtegrated Climate and CArbon model (INCCA). INCCA is the NCAR/DOE Parallel Coupled Model coupled to the IBIS terrestrial biosphere model and a modified-version of the OCMIP ocean biogeochemistry model. By year 2300, atmospheric CO2 reaches 1423 ppm the global climate warms by about 8 K relative to the pre-industrial control run. The climate sensitivity of this model for a doubling of atmospheric CO2 is estimated to be 2.1 K; however, an 8 K response to 1423 ppm of CO2 by year 2300 (with radiative forcing from non-CO2-GHGs) suggests that climate sensitivity may be higher on a warmer planet (i.e., climate may warm more rapidly than the log of CO2 concentration); if so, unrestrained emissions may lead to conditions that are more severe than might be expected by extrapolation of results from doubled-CO2 experiments. This work was performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.
B32A-07 11:50h
First results from coupling carbon cycle, nitrogen cycle, and climate in the NCAR CCSM3 model.
First results are presented describing both the offline performance of a coupled carbon-nitrogen cycle model operating within the NCAR Community Land Model (CLM-CN), and the coupled performance of CLM-CN operating within the NCAR Community Climate System Model, Version 3 (CCSM3). The new land model is fully prognostic for all energy, water, carbon, and nitrogen pools in the vegetation, litter, and soil. Atmospheric nitrogen deposition is prescribed from an offline atmospheric chemistry model for preindustrial, current and projected rates at 2100. The land model includes a relatively simple treatment of fire frequency and fractioanl area burned. Offline results demonstrate that CLM-CN performs well when driven with observed surface weather forcings. Experiments are performed in both coupled carbon-nitrogen mode and carbon-only mode to demonstrate the influence of this coupling on land net carbon fluxes. Experiments in offline mode show that the response of the carbon-only and carbon-nitrogen models to imposed warming is fundamentally different, with different time constants and different geographic distributions of sources and sinks. Coupled experiments demonstrate the influence of these dynamics on the evolution of land-atmosphere feedbacks under conditions of increasing fossil fuel consumption and shifting patterns of anthropogenic nitrogen deposition. The new model represents a significant step forward in our ability to represent multiple interactions among physical, biogeochemical, and anthropogenic components of the Earth System.
B32A-08 INVITED 12:05h
Earth System Modeling: An Integrated View of Planetary Behavior
Earth System Models (ESMs) are designed to assess how interactive processes between the different components of the Earth System influence the variations and trends that affect the planet and will continue to do so in the future. These models account for a variety of complex interlinked processes and provide a integrated view of the Earth system behavior. A major challenge for the next generation models will be to account for feedbacks associated with societal behavior. The paper will review recent progress made in the development of ESMs, highlight difficulties, and provide some insight on future challenges for the modeling community.