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Volume 1 Number 4:  1 November 1998

Editorial
CO2: The Utterly Amazing Air and Water Pollutant: Recent signals coming from the U.S. Environmental Protection Agency suggest it may soon classify CO2 as a pollutant.  Such an action would be a futile attempt to change the nature of nature.

Journal Reviews
Past Climate in Greenland: Borehole temperatures reveal that the thermal history of the surface of the Greenland Ice Sheet is not compatible with GCM predictions of CO2-induced global warming.

Five Centuries of Borehole Climate: This study uses temperature measurements from 358 boreholes around the world to reconstruct earth's climatic history over the past 500 years.

Retreat of the West Antarctic Ice Sheet: A brief but illuminating review of our knowledge of West Antarctic Ice Sheet properties and processes suggests no imminent major changes in sea level due to its shrinkage in response to global warming.

A Natural Thermostat to Keep a Lid on Global Warming?: Two most interesting papers, one from Nature and one from Science, describe a set of related phenomena that link the development of the Isthmus of Panama some 4.6 million years ago with the initiation of Northern Hemispheric glaciations.  The subsequent reconfiguration of earth's climate system seems to provide for a "natural thermostat" that limits global warming to levels characteristic of those that have prevailed throughout the several interglacials of the past two million years.

Mass Balance of the Antarctic Ice Sheet: Analyses of satellite radar altimeter data and snowfall data obtained from ice cores reveal that the grouonded Antarctic Ice Sheet has been in near-equilibrium for at least the past century and perhaps the last millennium.

Interactive Effects of low CO2 and Temperature on Bean: Young bean plants in growth chambers were exposed to both ambient or sub-ambient CO2 concentrations and moderate or high air temperatures to investigate the interactive effects of these variables on plant growth.  A strong CO2 by temperature interaction was discovered as evidenced by greater percentage enhancements in net photosynthesis and whole-plant biomass for thermally stressed plants in ambient CO2 relative to their controls at moderate temperature.

CO2-Temperature Interactions in Barley and Wheat: CO2-induced enhancements of leaf photosynthesis in wheat and barley were found to be in close agreement with the predictions of a biochemical model at moderate to high air temperatures, while at cooler temperatures the measured enhancements actually exceeded those predicted by the model.

Interactive Effects of Elevated CO2 and Temperature on Wheat: Spring wheat, sown in the field and grown in open-top chambers in Finland under interactive treatments of ambient and elevated CO2 and temperature, exhibited the greatest total biomass and grain yields with the elevated CO2 and temperature combination, indicating that any CO2-induced global warming will benefit wheat production in this area.

Interactive Effects of Temperature and CO2 on Birch: Yellow birch seedlings grown at 800 ppm CO2 for two months exhibited higher photosynthetic rates, total biomass and water-use efficiency than plants grown at 400 ppm CO2.  Although high temperatures increased transpiration and respiration, elevated CO2 significantly lowered the degree to which this occurred.

Interactive Effects of CO2 and Temperature on Cotton: In a growth chamber study of cotton grown at 350 and 700 ppm CO2, elevated CO2 enhanced individual leaf area by 20%, whole plant leaf area by 47% and biomass by 31 to 78% across a wide range of temperature treatments.

Photosynthetic Acclimation of Five Trees to Elevated CO2 and Temperature: Five tree seedlings exposed to an atmospheric CO2 concentration of 580 ppm for three months within controlled environment chambers increased their rates of net photosynthesis by an average of 28%, and their water-use efficiencies by 40 to 80%.