February 28, 2007
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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 10, NUMBER 5, MAY 1997
IMPACTS OF CLIMATE CHANGE: FORESTS AND ECOSYSTEMS
and Forests in the Great Plains," D.S. Guertin, W.E. Easterling (Dept.
Agric. Meteor., Univ. Nebraska, 236 Chase Hall, Lincoln NE 68583), J.R. Brandle,
BioScience, 47(5), 287-295, May 1997.
In addition to having economic effects on the extensive agriculture of this
region, climate change may also impact native plants and animals in these
agroecosystems. Changes in agricultural strategies (e.g. increased crop
irrigation) in response to climate change may amplify those impacts. Existing
models of forest dynamics offer a valuable starting point even though woodlands
are only a portion of Great Plains diversity. Deficiencies in large-scale
physiological models or forest gap models have limitations as well. The authors
propose a modeling framework that combines and extends features of existing gap
models into a design that can address the spatial heterogeneity of this region.
"Time Lags and
Novel Ecosystems in Response to Transient Climatic Change in Arctic Alaska,"
F.S. Chapin III (Dept. Integrative Biol., Univ. California, Berkeley CA 94720;
e-mail: firstname.lastname@example.org), A.M. Starfield, Clim. Change,
35(4), 449-461, Apr. 1997.
Estimates the future rate of advance of the Arctic treeline in response to
transient changes in temperature, precipitation and fire. Finds a 150-250 year
time lag in forestation of Alaskan tundra following climatic warming, and
suggests that, with rapid warming under dry conditions, there would be
development of boreal grassland steppe. The time lag and grassland development
would delay the positive feedback of vegetation change to climate change.
Two related items in
Nature, 385(6617), Feb. 13, 1997:
"An Oblique Slant on Deep-Sea Biodiversity," M.A. Rex (Dept.
Biol., Univ. Massachusetts, 100 Morrissey Blvd., Boston MA 02125), 577-578. Just
30 years ago, the discovery of surprisingly high species diversity in the deep
sea inspired a period of intense ecological research there. The following study
shows that the deep seas are not immune from large-scale shifts in climate.
"Orbital Forcing of Deep-Sea Benthic Species Diversity," T.M.
Cronin (Climate History Team, 955, U.S. Geol. Survey, Reston VA 20192), M.E.
Raymo, 624 ff. This study shows that Pliocene (2.85-2.40 Myr) deep-sea North
Atlantic ostracod (Crustacea) species diversity is related to solar insolations
caused by 41,000-yr cycles of the Earth's obliquity (tilt). Temporal changes in
diversity correlate with independent climate indicators (glacial and
interglacial periods). Diversity oscillations reflect large-scale response of
the benthic community to climatically driven changes in either thermohaline
circulation, bottom temperature (or temperature-related factors) and food, and a
coupling of benthic diversity to surface productivity.
Greenhouse Summer Dryness to Changes in Plant Rooting Characteristics,"
P.C.D. Milly (NOAA/GFDL, POB 308, Princeton NJ 08542; e-mail: email@example.com),
Geophys. Res. Lett., 24(3), 269-271, Feb. 1, 1997.
A possible consequence of increased greenhouse gases in middle latitudes is "summer
dryness," a decrease of summer plant-available soil water. The model used
in this study suggests that a 14% decrease of soil volume whose water is
accessible to plant roots would generate the same summer dryness as would an
equilibrium doubling of atmospheric CO2. Given their apparently
critical role in global hydroclimatic change, such changes of rooting
characteristics should be carefully evaluated.
Two items in Clim.
Change, 35(1), Jan. 1997.
"Modelling Climate Change Impacts on Ecosystems Using Linked Models and
a GIS [Geographic Information System]," A. Eatherall (Inst. Hydrol.,
Maclean Bldg., Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB, UK), 17-34.
Results indicate a decrease in grassland productivity under a changed climate
with possible large consequences for water resource planning in the U.K. This
study also highlights the need to use linked, process-based models, using
spatial data wherever possible, for climate change impact studies on ecosystems.
Failure to do so may result in important control processes being omitted from
the modeling process.
"Climate Change and the Bathurst Caribou Herd in the Northwest
Territories, Canada," J. Brotton (Dept. Geog., Univ. Waterloo, Waterloo ON
N2L 3G1, Can.), G. Wall, 35-52. The locations frequented by the caribou herd
were determined, and the 1951-1980 average monthly temperatures and total
monthly precipitation amounts ascertained. Climate change scenarios indicate a
possible increase in winter snowfall, and increased insect harassment of caribou
in summer from increased temperatures. These trends suggest a reduced hunting
potential of the herd.
Responses to Carbon Dioxide, Temperature and Nitrogen: A Model Analysis,"
J.H.M. Thornley (Inst. Terrestrial Ecol.-ITE, Bush Estate, Penicuik, Midlothian
EH26 0QB, UK), M.G.R. Cannell, Plant, Cell & Environ., 19(12),
1331-1348, Dec. 1996.
Used the ITE Edinburgh Forest model, one of the most comprehensive models of
its kind, which describes diurnal and seasonal changes of C, N, and H2O in a
fully coupled forest-soil system. Simulated a managed conifer plantation in
upland Britain to examine transient effects on forest growth of an IS92a
scenario of increasing CO2 and temperature over two future
rotations, and the equilibrium effects of all combinations of increased CO2,
mean annual temperature and annual inputs of N. Details eight major conclusions,
which may lead to decreases or increases of growth. Projected increases in CO2
and temperature (IS92a) are likely to increase net ecosystem productivity and
carbon sequestration in temperate forests.
Climate Change Effects on Loblolly Pine Forest Productivity and Drainage Across
the Southern United States," S.G. McNulty (USDA Forest Service, 1509
Varsity Dr., Raleigh NC 27606), J.M. Vose, W.T. Swank, Ambio, 25(7),
449-453, Nov. 1996.
Used a well validated, physiologically based, forest ecosystem model that
combined soil and vegetation data with six climate change scenarios for the
states of Texas, Mississippi, Florida and Virginia. Across the sites, increasing
air temperature would have much greater impact on pine forest hydrology and
productivity than would changes in precipitation. These changes could seriously
impact the structure and function of these forests by decreasing net primary
productivity and total leaf area.
THE APPLICATION OF PATCH MODELS OF VEGETATION DYNAMICS TO GLOBAL CHANGE ISSUES,
T.M. Smith, Ed. (Dept. Environ. Sci., Univ. Virginia, Charlottesville VA 22903),
Clim. Change, 34(2), Oct. 1996. Consists of 15 papers based on
research in Europe and North America, including the following overview article.
"A Review of Forest Patch Models and Their Application to Global Change
Research," H.H. Shugart (address above), T.M. Smith, 131-153.
Provides a description of the structure of patch (gap) models of vegetation
dynamics; examines some of the problems with their use in examining global
change issues; explains how recent model developments attempt to overcome these
limitations; and suggests areas for future research.
Two items in World
Resource Review, 8(3), Sep. 1996:
"Long-Term Forest Monitoring in Switzerland: Assessing Climate Change
Impacts," N. Kräuchi (Swiss Fed. Inst. for Forest, Snow &
Landscape Res. WSL, CH-8903, Birmensdorf, Switz.), 370-381. Discusses
successional characteristics of, and potential risks to forest ecosystems as
influenced by a changing environment. To assess risks, uses FORSUM, a forest
succession model for Central Europe, combined with data from 15 monitoring
"Effects of Climate Change on Mountain Ecosystems - Upward Shifting of
Alpine Plants," H. Pauli (Dept. Vegetation Ecol., Univ. Vienna, Althanstr.
14, 1091 Vienna, Austria), M. Gottfried, G. Grabherr, 382-390. Presents
empirical evidence of the upward movement of vascular plants in the European
Alps. Comparison of data collected in 1992-1993 from 30 high summits with
historical data shows an increase in species at 70% of the summits. Approximate
rates of upward movement for common alpine plants were calculated to be between
zero and four meters per decade. This result may already be a "measurable"
result of global warming since the 19th century.
of Montane Ecotones as Indicators of Global Climatic Change," J.A. Kupfer
(Dept. Geog., Univ. Memphis, Memphis TN 38152), D.M. Cairns, Prog. Phys.
Geog., 20(3), 253-272, Sep. 1996.
The locations of ecotones, the transitions between adjacent ecosystems or
biomes, may serve as indicators of climate change. This article addresses the
use of two montane ecotones-the alpine tree-line ecotone, and the
deciduous/Boreal forest ecotone. The authors outline the factors that create and
maintain each ecotone's position, assess the projected response to global
warming; and discuss the usefulness of both ecotones as indicators of climate
"Responses in the
Growth of the Northern Forests to a CO2-Induced Climatic Change, as
Evaluated by the Frankfurt Biosphere Model - (FBM)," C. Häger (Inst.
Phys. & Theoret. Chem., J.W. Goethe Univ., Marie-Curie Str. 11, 60439
Frankfurt, Ger.), G. Würth et al., World Resource Review,
8(2), 178-197, June 1996.
This mechanistic, prognostic compartment model of the terrestrial biosphere
simulates the carbon exchange fluxes between the vegetation and the atmosphere
with a spatial resolution of 0.5° X 0.5° on a global scale.
Discusses the use of this model and the assumptions made, including a
fertilization effect from increased CO2. Found that the increase in
maximum biomass in the future greenhouse climate is accompanied by an
acceleration of stand regrowth, especially in the Boreal forest. If Northern
forest managers can raise the rotation, and if the harvest is used as a
substitute for fossil fuel, the carbon sink strength of the forest sector is
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