Editorial
Trouble in Climate-Model Paradise: An important new study demonstrates that one of the most basic predictions of current climate models is about as wrong as it could possibly be.

Medieval Warm Period Record of the Week
This issue's Medieval Warm Period Record of the Week comes from Eastern Sierra Nevada Range, California, USA.

Subject Index Summary
Tannins (Birch Trees) How do the tannin concentrations of the foliage and roots of birch trees respond to atmospheric CO2 enrichment? ... and what are the ramifications of this phenomenon?

Journal Reviews
The Role of Northern Peatlands in Global Climate Change: Do they provide a positive or negative impetus for global warming?

A Thousand-Year Pollen Record of Environmental Change in the Northern Altai Mountain Region of Southern Siberia: What does it tell us about the nature and uniqueness of 20th-century temperatures there?

Fifteen Hundred Years of Climate Change in Central Mexico: What does the record reveal about the primary manifestation of the Medieval Warm Period in this part of the country ... and beyond?

Effect of Elevated CO2 on Vegetative Storage Proteins in Alfalfa Taproots: What is the effect? ... and why is it important?

Effects of Elevated CO2 and O3 on the Reproductive Fitness of Paper Birch Trees: What are they? ... and how do the typically beneficial effects of CO2 compare with the generally deleterious effects of O3?