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Global Climate Change Digest
A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999

FROM VOLUME 11, NUMBER 11, NOVEMBER 1998

PROFESSIONAL PUBLICATIONS...
OF GENERAL INTEREST

Item #d98nov1

“Changes in the Carbon Balance of Tropical Forests: Evidence from Long-Term Plots,” O. L. Phillips (O.Phillips@geog.leeds.ac.uk) et al.,Science 282, 439-442 (1998).

The carbon of the standing stock in 50 experimental plots in mature, humid, tropical, South American forests was measured for 18 years. In 38 of these plots, biomass gain from tree growth exceeded losses from tree death. In aggregate, the plots accumulated 0.71 ton of carbon per hectare per year (±48%), indicating that such forests are significant carbon sinks.

Item #d98nov2

“Carbon Dioxide Emissions from European Estuaries,” Michel Frankignoulle (Michel.Frankignoulle@ulg.ac.be) et al.,Science 282, 434-444.

Rivers carry dissolved and particulate material from continental interiors to the ocean. Where they meet the sea, they usually broaden out into an estuary, and tidal influences temporarily hold the waters in that estuary as the entrained material decomposes. As a result, estuaries have high levels of dissolved CO₂ and high CO₂ fluxes to the atmosphere. Measurements of wide estuaries revealed net daily fluxes to the atmosphere on the order of hundreds of tons of CO₂ per estuary. Extrapolating the measurements to all of Europe indicates an estuarine release of CO₂ of 30 to 60 million tons per year, which is 5 to 10% of the land-based industrial and transport emissions.

Item #d98nov3

“Energy Implications of Future Stabilization of Atmospheric CO₂ Content,” M. I. Hoffert et al., Nature 395, 881-884 (1998).

A carbon-cycle/energy model was used to estimate the carbon-emission-free power that would be needed to achieve, under various attainment scenarios, the commitments called for by the Kyoto Protocol. Analysis of a standard baseline case indicated that 10 TW of CO₂-free generation would need to be added to the power-generation portfolio by the year 2050 to meet demand. This value is about 10 times the power currently generated by nonfossil power plants. In view of the results from all the scenarios analyzed, continued economic growth will require innovative, cost-effective, and carbon-emission-free technologies to produce the primary power required in the coming decades, even with sustained improvement in the economic productivity of primary energy. If even stricter emission limits are chosen, meeting those goals will be even more challenging. The results suggest the need for massive investments in innovative energy research.

Item #d98nov4

“Climate Change Record in Subsurface Temperatures: A Global Perspective,”H. N. Pollack, Shaopeng Huang, and Po-Yu Shen,Science 282, 279-281.

Heat that strikes and is absorbed by the surface of the Earth travels through the crust, producing a subtle, but detectable, vertical variation in temperature. Geothermal data from 358 boreholes in North America, central Europe, southern Africa, and Australia were studied to reconstruct the climate regimes that would have produced the relic temperatures observed. The data indicate that the average temperature of the surface of the Earth has increased about 0.5° C during the 20th century, that the 20th century was the warmest of the past five centuries, and that the mean temperature of the Earth’s surface has warmed about 1.0° C during those five centuries.

Item #d98nov5

“Particle Nucleation in the Tropical Boundary Layer and Its Coupling to Marine Sulfur Sources,” A. D. Clarke et al.,Science 282, 89-92 (1998).

New particles were observed to form in a tropical marine boundary layer. Real-time measurements of dimethylsulfide, sulfur dioxide, gaseous sulfuric acid, hydroxide, and ozone concentrations and of temperature, relative humidity, aerosol size and number distribution, and aerosol surface area linked these newly formed particles to the natural marine sulfur cycle. Chemical models previously presumed that cloud-nucleating aerosols originated elsewhere and drifted over the ocean. This evidence indicates that the oceans themselves originate the precursors for these aerosols.

Item #d98nov6

“Early Maritime Economy and El Niño Events at Quebrada Tacahuay, Peru,” D. K. Keefer (dkeefer@mojave.wr.usgs.gov) et al.,Science 281, 1833-1835 (1998).

Habitation of a coastal site at Quebrada Tacahuay, Peru, has been dated to 12,700 to 12,500 years before the present. Sediments above and below the discovered artifacts seem likely to have been produced by El Niño events, indicating that such events occurred during the Pleistocene as well as the early and middle Holocene.