Michael Dalton

Global demographic trends and future carbon emissions

Substantial changes in population size, age structure, and urbanization are expected in many parts of the world this century. Although such changes can affect energy use and greenhouse gas emissions, emissions scenario analyses have either left them out or treated them in a fragmentary or overly simplified manner. We carry out a comprehensive assessment of the implications of demographic change for global emissions of carbon dioxide. Using an energy–economic growth model that accounts for a range of demographic dynamics, we show that slowing population growth could provide 16–29% of the emissions reductions suggested to be necessary by 2050 to avoid dangerous climate change. We also find that aging and urbanization can substantially influence emissions in particular world regions.

Demographic change and carbon dioxide emissions

Relations between demographic change and emissions of the major greenhouse gas carbon dioxide (CO(2)) have been studied from different perspectives, but most projections of future emissions only partly take demographic influences into account. We review two types of evidence for how CO(2) emissions from the use of fossil fuels are affected by demographic factors such as population growth or decline, ageing, urbanisation, and changes in household size. First, empirical analyses of historical trends tend to show that CO(2) emissions from energy use respond almost proportionately to changes in population size and that ageing and urbanisation have less than proportional but statistically significant effects. Second, scenario analyses show that alternative population growth paths could have substantial effects on global emissions of CO(2) several decades from now, and that ageing and urbanisation can have important effects in particular world regions. These results imply that policies that slow population growth would probably also have climate-related benefits.

ECONOMIC IMPACTS OF CHANGES IN AN ALASKA CRAB FISHERY FROM OCEAN ACIDIFICATION

A dynamic computable general equilibrium (CGE) model is linked to a bioeconomic model for the Bristol Bay red king crab (BBRKC) fishery to analyze regional economic impacts of ocean acidification (OA)-induced changes in fishery yields. Yield projections based on two alternative forms (linear versus nonlinear) of OA effects on the survival of juvenile BBRKC are compared to a baseline without OA effects. Results demonstrate considerable uncertainty in yields, and show that economic impacts are sensitive to the form of OA effects, and to changes in the world price of BBRKC (Q22, Q54, Q57, R13).

NOAA’s Alaska Ocean Acidification Research Plan for FY18-FY20.

Dissolution of anthropogenic CO2 has reduced global mean surface water 0.1 pH units below preindustrial levels, a change of about 26% (Caldeira and Wickett 2003, Orr et al. 2005). In addition, deep oceanic waters are depleted in carbonate due to respiration resulting in a saturation depth below which calcium carbonate dissolves. Thus, decreased carbonate ion concentration hinders the formation of shells and support structures by some calcifying organisms (Caldeira and Wickett 2003, Feely et al. 2004, Orr et al. 2005). Crustaceans are calcifying organisms that are critical to marine food webs and support important commercial fisheries. In the North Pacific Ocean, where the saturation depth is relatively shallow due to the cold temperature and age of advected deep water masses, Golden king crab (Lithodes aequispinus), snow crab (Chionoecetes opilio), Tanner crab (Chionoecetes bairdi), and red king crab (Paralithodes camtschaticus) are ecologically and economically important crustaceans. The influence of lower pH and decreased carbonate ion concentration in seawater on the condition, survival, and shell calcium carbonate content of snow crabs in Alaska are unknown. Acidified waters can have a significant effect on the development (Findlay et al. 2009, Parker et al. 2009), development time (Findlay et al. 2009), viability (Kurihara et al. 2004a), and even behavior (Ellis et al. 2009) of the embryos of marine invertebrates (though see Arnold et al. 2009). Further, acidified waters can reduce fertilization success (Parker et al. 2009), the hatching success of embryos (Kurihara et al. 2004a), and the fecundity of females (Kurihara et al. 2004b). We propose to conduct experimental research on golden king crab juveniles, which are currently available from previous experimental treatments on embryological development and larval survival. Next we propose to initiate studies on snow crab. Snow crab culturing is more difficult than the other species, however, the important role of snow crab ecologically and economically to Alaska coastal communities necessitates that we test the effects of OA on this species. Snow crab adults (ovigerous females) will be included in experiments in the summer of 2014 so that embryological studies can be conducted in FY15. Further, snow crab will be treated similarly to its congener, Tanner crab, so that direct comparisons can be made to the physiological response of