Predicted increases in atmospheric carbon dioxide (CO2) concentrations often reduce nutritional quality for herbivores by increasing the C:N ratio of plant tissue. This frequently triggers compensatory feeding by aboveground herbivores, whereby they consume more shoot material in an attempt to meet their nutritional needs. Little, however, is known about how root herbivores respond to such chan...

A homemade CO2-laser photoacoustic spectrometer has been used for monitoring CO2 in gas samples extracted under vacuum from the wood of old spruce disc tree-rings for a ∼60 year series. The experimental results show that (1) the CO2 concentration exhibits annual trends correlated with an increase in atmospheric CO2 in a number of cases; (2) at the time when the annual CO2 trend changes from pos...

Title of Document: CARBON CYCLE DATA ASSIMILATION USING A COUPLED ATMOSPHEREVEGETATION MODEL AND THE LOCAL ENSEMBLE TRANSFORM KALMAN FILTER Ji Sun Kang, Doctor of Philosophy, 2009 Directed By: Professor Eugenia Kalnay Department of Atmospheric and Oceanic Science We develop and test new methodologies to best estimate CO2 fluxes on the Earth’s surface by assimilating observations of atmospheric ...

We present several equilibrium runs under varying atmospheric CO2 concentrations using the University of Victoria Earth System Climate Model (UVic ESCM). The model shows two very different responses: for CO2 concentrations of 400 ppm or lower, the system evolves into an equilibrium state. For CO2 concentrations of 440 ppm or higher, the system starts oscillating between a state with vigorous de...

A decrease in the 13C/12C ratio of atmospheric CO2 has been documented by direct observations since 1978 and from ice core measurements since the industrial revolution. This decrease, known as the 13C-Suess effect, is driven primarily by the input of fossil fuel-derived CO2 but is also sensitive to land and ocean carbon cycling and uptake. Using updated records, we show that no plausible combin...

One of the industrial revolution’s most insidious environmental legacies—dangerous atmospheric concentrations of CO2—can no longer be ignored. With “business-as-usual” projections rapidly approaching a grim horizon of climatic consequences, there is an urgent need to develop innovative strategies for CO2 stabilization that either reduce emissions through improved energy efficiency, or eliminate...

The crustal Urey cycle of CO2 involving silicate weathering and metamorphism acts as a dynamic climate buffer. In this cycle, warmer temperatures speed silicate weathering and carbonate formation, reducing atmospheric CO2 and thereby inducing global cooling. Over long periods of time, cycling of CO2 into and out of the mantle also dynamically buffers CO2. In the mantle cycle, CO2 is outgassed a...

In this paper, we examine the potential of carbon capture and sequestration technologies to make a significant contribution to national and global efforts to control carbon dioxide (CO2) emissions. We examine the performance of these technologies under two alternative future energy-policy scenarios. We conclude that carbon capture and sequestration technologies could indeed play a significant r...

Global climate change has been modifying ecosystem carbon cycling, which has produced feedbacks on climate by affecting the concentration of atmospheric CO2. The importance of biospheric CO2 uptake or release to climate change has generated great interest in quantifying the dynamic responses of terrestrial ecosystem carbon cycling to climate change. However, less attention has been given to Afr...

Elevated atmospheric CO2 concentrations ([CO2]) have been hypothesized to increase photosynthesis rates and volatile organic compound (VOC) emissions; however, field measurements from a select group of conifer and angiosperm trees have shown that VOC emissions are in fact not affected or reduced by elevated CO2 levels. To broaden the understanding of how different plant species respond to eleva...