Newest Climate Briefs Discuss Natural Climate Variability, Economic Implications of Carbon Cycle Uncertainty
The most recent in EPRI’s series of Climate Briefs are as follows:

• Progress in Understanding Natural Climate Variability (1014807).  With uncertainty in the degree of natural climate variability, furthering our understanding and narrowing that uncertainty is critical in discerning the human influence on the observed global climate change.  To help address these uncertainties and to identify ways to advance the state of knowledge regarding natural climate variation, EPRI, along with both the U.S. and Swiss National Science Foundations, helped fund a four-day workshop entitled “Past Millenia Climate Variability:  Proxy-Base Reconstructions, Modeling and Methodology – Synthesis and Outlook” in Switzerland in June 2006.  This Climate Brief discusses the results of that workshop.  Among these results was the conclusion that “Late 20th century warming is likely anomalous (human caused) in the context of the past 1000 years at hemispheric scales.  There is evidence for periods of cooling and warming that occur on all timescales and on all spatial scales.”
• The Economic Implications of Carbon Cycle Uncertainty (1014819).  The Intergovernmental Panel on Climate Change (IPCC) has concluded that atmospheric concentrations of carbon dioxide (CO₂) have increased over the past century due to human activity.  Further, significant increases in CO₂ emissions from fossil fuel combustion are expected over the next several decades.  Studies to explore the economic implications of stabilizing atmospheric concentrations of CO₂ have traditionally ignored carbon cycle uncertainty.  However, the economic cost of stabilizing the concentration of CO₂ is highly dependent on the future rate of carbon uptake by natural processes.  This Climate Brief explores how carbon cycle uncertainties affect the economic costs of achieving a given CO₂ concentration target.