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Economics & Social Sciences Research Program

AFSC Social Scientists Examine the Connections between Environment and Demography

population distribution map, see caption
Bering Sea and Aleutian Islands 2005 population distribution (indicated by size of circle) and each community’s population trend between 1990 and 2005 (indicated by color of circle).

AFSC Social Scientists Examine the Connections between Environment and Demography Drs. Jennifer Sepez and Michael Dalton of the Economics and Social Sciences Research (ESSR) Program both presented research in environment and demography at the Population Association of America (PAA) meetings in New York, 29-31 March 2007.

Dr. Sepez presented “Recent and Historic Population Trends in the Bering Sea and Aleutian Islands: Hubs and Spokes, Booms and Busts,” along with coauthor Amanda Poole of the University of Washington. The paper reports on research they undertook last year looking at possible connections between demography and climate change in the Bering Sea/Aleutian Islands (BSAI). Human populations in that area have been increasing since the 1920s, a trend which could accelerate or reverse under different global climate change scenarios (see map above).

In larger hub communities, a net in-migration has been generated by foreign-born immigrants drawn as labor to the seafood processing industry. In many small villages, net out-migration for education and economic opportunity is countered by a high birth rate among Native Alaskan populations. Most communities that have experienced negative population growth in the last 15 years are those closely linked to the salmon fishery which has suffered economically with the growth of global production and trade of farmed fish.

This research is part of a larger project which will attempt to construct models that predict potential demographic impacts of ecosystem changes stemming from global climate change. An early version of the paper was published in the 2006 SAFE report. An updated version of the paper can be found on the web at

Dr. Dalton presented some of his recent work on a global economic growth model in a session called Environmental Consequences of Population Growth/Decline. Further work on the Alaska and U.S. components of the global model is described in the section on Alaska Fisheries and Global Trade.

The presentation at PAA, “Demographic Change and Future Carbon Emissions in China and India,” is based on a paper by Dalton, Leiwen Jiang of Brown University, Shonali Pachauri, and Brian O’Neill, both of the International Institute for Applied Systems Analysis (IIASA). This paper investigates whether projected changes in the demographic characteristics of Chinese and Indian households over the next century could have a substantial influence on consumption, economic growth, energy demand, and carbon dioxide emissions.

The authors use new household projections for China and India that model changes in population size, urbanization, and the size and age structure of households over the next 100 years. The initial economic characteristics of different household types, including demand for consumer goods, supplies of labor, and capital, are estimated from household surveys and production data for each country. A global energy-economic growth model simulates economic growth as well as changes in consumption of various goods, direct and indirect energy demand, and carbon emissions over time. Effects of demographic change are compared under different scenarios from the Intergovernmental Panel on Climate Change (IPCC) that include technical change.

Results show that explicit consideration of urbanization leads to a substantial increase in projected emissions, while aging leads to a decrease. The net effect of demographic change is to increase projected emissions from China by 45% by the end of the century, and from India, by 15-35%. The draft paper is available online at

By Jennifer Sepez and Mike Dalton

Estimating Economic Base Relationships for Alaska Fisheries Using Borough-level North American Industry Classification System (NAICS) Data

Virtually all regional economic impact models developed so far for analysis of U.S. fisheries are static models. With static models, it is impossible to address the timing of the impacts, which needs to be considered in formulating fishery management policies. An alternative model that avoids these weaknesses is a dynamic economic base model, which is often implemented with a vector autoregressive error correction (VECM) model.

The VECM model is able to estimate the time and magnitudes of regional economic impacts in response to shocks to seafood industries as well as the long-run relationships between basic industries (including seafood industry) and nonbasic (supporting) industries. Using monthly employment data at regional levels from 1990 to 2000, Dr. Chang Seung, ESSR Program, developed VECM models for two fishery-dependent regions in Alaska – the Southwest and Gulf Coast regions.

In the model, the dynamic impacts of seafood industry on the economies of the two regions were investigated. Recently, the Alaska Department of Labor and Workforce Development completed a project for NMFS in which borough–level monthly employment data was prepared using the North American Industry Classification System (NAICS) system.

This data will allow us to conduct research in which the impacts of seafood industry can be examined for each of the fishery-dependent boroughs and census areas. Using this NAICS data, Dr. Seung will develop dynamic economic base models for fishery-dependent boroughs and census areas. Depending on whether a funding proposal is successful, the project may be jointly conducted with Professor Sung Ahn at Washington State University.

By Chang Seung

BSAI Crab Economic Data Reporting Data: Protocols for Confidentiality and Data Quality

Based on public testimony and a recommendation from the Advisory Panel (AP) at the December 2006 meeting, the NPFMC passed a motion directing staff to develop protocols concerning data collected under the BSAI crab rationalization Economic Data Reporting (EDR) Program. The protocols apply to two general areas: 1) maintaining data confidentiality and 2) assessing the quality of the data to ensure accuracy.

ESSR Program scientists prepared a discussion paper to outline the legal, regulatory, and administrative standards that apply to confidentiality and data quality, and remaining issues to be resolved in regard to crab EDR data. The paper sets forth the process that AFSC staff, in collaboration with Council and NMFS Alaska Region staff, will undertake to develop both sets of protocols to ensure that industry and Council concerns regarding the crab EDR program are addressed. The paper was presented at the March/April Council meeting and received the endorsement of the AP and Council (time limitations did not allow the Council’s Scientific and Statistical Committee to receive a presentation of the paper).

The protocols will be developed with public, industry, and scientific peer input, with workshops to be held during summer 2007. Protocols are expected to be in place concurrent with completion of 2006 EDR data collection and verification (4th quarter, FY07), which will provide the second year of economic and social data collected post-rationalization.

By Brian Garber-Yonts

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