Daily Archives: February 1, 2013

Biomass burning has decreased over the prior decade…

Jennifer R. Marlona, Patrick J. Bartleinb, Anne-Laure Daniauc, Sandy P. Harrisone, Shira Y. Maezumif, Mitchell J. Powerf, Willy Tinnerg, Boris Vanniéreh. Global biomass burning: a synthesis and review of Holocene paleofire records and their controls. Quaternary Science Reviews, Volume 65, 1 April 2013, Pages 5–25

We synthesize existing sedimentary charcoal records to reconstruct Holocene fire history at regional, continental and global scales. The reconstructions are compared with the two potential controls of burning at these broad scales – changes in climate and human activities – to assess their relative importance on trends in biomass burning. Here we consider several hypotheses that have been advanced to explain the Holocene record of fire, including climate, human activities and synergies between the two. Our results suggest that 1) episodes of high fire activity were relatively common in the early Holocene and were consistent with climate changes despite low global temperatures and low levels of biomass burning globally; 2) there is little evidence from the paleofire record to support the Early Anthropocene Hypothesis of human modification of the global carbon cycle; 3) there was a nearly-global increase in fire activity from 3 to 2 ka that is difficult to explain with either climate or humans, but the widespread and synchronous nature of the increase suggests at least a partial climate forcing; and 4) burning during the past century generally decreased but was spatially variable; it declined sharply in many areas, but there were also large increases (e.g., Australia and parts of Europe). Our analysis does not exclude an important role for human activities on global biomass burning during the Holocene, but instead provides evidence for a pervasive influence of climate across multiple spatial and temporal scales.

Click here for full paper (fee).

The “Hot Spot” is still missing….

As discussed here, physical measurements using weather balloons fail to find evidence of the “amplification” required to make the CO2 theory of global warming work to match the climate models…….When a model does not match the observations, a scientist would change the model. Of course, in climate modeling “science” today, the practice is to ignor the measurements that are contrary to the model for sake of the narrative…….A model that does not “correspond” physical reality is not sound….nor is it useful or necessary for making good planning decisions….

Glacier volume 43% less than IPCC estimate…

A. Grinsted. An estimate of global glacier volume. The Cryosphere Discuss., 6, 3647-3666, 2012

I asses the feasibility of multi-variate scaling relationships to estimate glacier volume from glacier inventory data. I calibrate scaling laws against volume observations of optimized towards the purpose of estimating the total global ice volume. This is applied individually to each record in the Randolph Glacier Inventory which is the first globally complete inventory of glaciers and ice caps. I estimate that the total volume of all glaciers in the world is 0.35 ± 0.07 m sea level equivalent. This is substantially less than a recent state-of-the-art estimate. Area volume scaling bias issues for large ice masses, and incomplete inventory data are offered as explanations for the difference.

Click here for full paper (Open Access).

USGS finds no well contamination from Fayetteville Shale exploration

LITTLE ROCK, Ark. – A study (click here) that examined the water quality of 127 shallow domestic wells in the Fayetteville Shale natural gas production area of Arkansas found no groundwater contamination associated with gas production, according to a report released today by the U.S. Geological Survey.

Scientists analyzed water-quality data from samples taken in Van Buren and Faulkner counties in 2011, focusing on chloride concentrations from 127 wells and methane concentrations and carbon isotope ratios from a subsample of 51 wells.

“For more than one hundred years, the USGS has been a source of freely available, unbiased information on our natural resources such as oil, gas, and water, helping government and local leaders make wise decisions for the public good,” said USGS Director Marcia McNutt. “This new study is important in terms of finding no significant effects on groundwater quality from shale gas development within the area of sampling.”

Chloride is a naturally occurring ion that is found at elevated levels in waters associated with gas production.  Chloride moves easily through groundwater without reacting with other ions or compounds in solution, making it is a good indicator of whether chemicals used during hydraulic fracturing are reaching groundwater.  In this case, the chloride concentrations from this study were not higher than samples taken from nearby areas from 1951 through 1983.

Methane is the primary component of natural gas, but also can be found naturally in shallow shale formations in the Fayetteville Shale area that are used as sources of water for domestic supplies.  What methane was found in the water, taken from domestic wells, was either naturally occurring, or could not be attributed to natural gas production activities.

“None of the data that we have looked at as part of this study suggests that any groundwater contamination is resulting from natural gas production activities,” said USGS hydrologist Tim Kresse.  “However, this study does not speak to other wells that were not sampled, every chemical used during the hydraulic fracturing process, or water quality changes that might take longer to occur. It does provide a baseline to use to evaluate any possible changes in the future.”

Summary of results:

Groundwater chemistry in the shallow aquifer system in the study area is a result of natural processes

  • Chloride concentrations were not higher in the 2011 samples than in samples from nearby areas collected from 1951 through 1983
  • Chloride concentrations from wells within 2 miles of a gas-production well were similar to concentrations from wells more than 2 miles from a gas-production well
  • Methane concentrations and carbon isotope ratios indicate that almost all methane in groundwater samples is naturally occurring as a result of biological processes in shallow shale formations used as a source of water for domestic purposes and did not originate from the Fayetteville Shale

The Fayetteville Shale serves as an unconventional gas reservoir across parts of six counties in north-central Arkansas, ranging in thickness from approximately 50 to 550 feet and varying in depth from approximately 1,500 to 6,500 feet below the ground surface. Drilling and production of gas wells began in 2004 and, as of April 2012, approximately 4,000 producing gas wells had been completed in the Fayetteville Shale.

The report, “Shallow Groundwater Quality and Geochemistry in the Fayetteville Shale Gas-Production Area, North-Central Arkansas, 2011” by Timothy M. Kresse, Nathaniel R. Warner, Phillip D. Hays, Adrian Down, Avner Vengosh, and Robert B. Jackson, is available online.