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Volume 4 Number 20:  16 May 2001

Temperature Record of the Week
This issue's Temperature Record of the week is from Tucumcari, New Mexico. Visit our U.S. Climate Data section to plot and view these data for yourself.

Current Editorial
The CO2-Climate Debate: Who Holds the Moral High Ground?: Some of the readers of our editorial page fervently believe it is not us.  They could be right.  Then again, they could be wrong.  The answer has everything to do with what one knows and does not know, and how one charts one's course of action within that context.

Subject Index Summaries
Greenhouse Effect: As atmospheric concentrations of several greenhouse gases have increased over the past several years, there is evidence for a concomitant increase in the greenhouse effect of the cloud-free atmosphere.  However, there is also evidence for a cloud-driven phenomenon that could counteract this impetus for warming.  Which effect is winning (among a whole host of other related phenomena) is the crux of the climate change debate.

Growth Response to CO2 (Roots): A survey of the recently published literature indicates that increases in the air’s CO2 content positively influence plant roots in a physical manner by increasing their biomass, length and surface area.  In addition, elevated CO2 impacts various physiological processes, such as the production and turnover of fine roots, root exudation and root respiration, in ways that lead to enhanced carbon inputs to soils.

Current Journal Reviews
A 200-Year Record of European Air Pressure: This important real-world data set indicates – contrary to climate model predictions that global warming will produce more extreme and variable weather – that weather in Europe has actually become less variable or extreme than it was during the significantly cooler Little Ice Age.

Climate Variability in the Southern Balkans: Temperature and precipitation data from the southern Balkans and eastern Mediterranean regions reveal that today’s climate in that part of the world is much more stable than it was during the cold of the Little Ice Age.

Elevated CO2 Increases Yield in Water-Stressed Sorghum: In spite of experiencing soil moisture levels that were only a third as much as those experienced by well-watered plants, water-stressed sorghum plants exposed to air containing an additional 200 ppm CO2 increased their final yield by 15%.

World’s First Free-Air CO2 Enrichment Study of a Stand of Sweetgum Trees: Young trees growing in relative isolation typically grow bigger and better when the air’s CO2 concentration is experimentally increased.  But what about older trees growing so close together in a forest that their upper branches form a complete canopy overhead?  Can they boost their growth in response to extra CO2?