Zero-Waste Mine Reclamation: Coal + Steel + Human Wastes = Soil

by Zoe Dilles

Coal has seen a worldwide growth in production in recent decades despite health as well as environmental concerns as coal combustion is cited as the primary CO2 atmospheric source. In this age anthropogenic climate change, air emissions often overshadow the threats posed coalmine waste rock, which has far-reaching ecological effects from its metal and acid contents. Mixes of coal waste rock with other substances to balance the concentration of nutrients and minerals can order to promote plant growth. Fabricated soils have the potential to reduce landfill disposal as well as mitigate the issues attendant to reclamation reliant on borrowed soils, often leading to deforestation and hydrologic changes. Continue reading

Determinants of Technology Innovation in the Transportation Sector: Oil Endowments

by Russell Salazar

The development of energy-efficient technologies is becoming increasingly necessary in a warming world. How can countries encourage firms and individuals to innovate more eco-friendly technologies in an effective manner? Kim (2014) takes a closer look at the socio-economic motivators for the development of energy-efficient technologies, with a primary focus on the transportation sector. The study presents empirical evidence to support the claim that smaller oil endowments result in a greater incentive for the development of more eco-friendly vehicles and energy-efficient designs. These findings, combined with explanations from related economic theory, provide insight into potential sustainability schemes for policy makers around the world. Continue reading

Pollution and Politics

by Jackson Cooney

Republican senator, Mitch McConnell, of Kentucky has been pushing states to ignore President Obama’s global warming regulations. He argues that the administration’s anti-coal initiative aims to destroy America’s power generation under the pretense of protecting the climate. The EPA along with the President is requiring each state to submit a plan outlining how they are going to cut coal plant pollution. These plans will lead to the shutdown of hundreds of power plants in the Administration’s attempt to rely more heavily on renewable energy sources. As of now, 12 states have filed lawsuits in protest of this plan. However Senator McConnell has advised that the best way to fight this initiative would be to refuse to submit state plans. Continue reading

Depletion of Fossil Fuels and Climate Change

by Makari Krause

Fossil fuels, while a large part of our energy production, are not a renewable resource and will eventually be depleted. Current climate models, such as the ones used by the IPCC, use levels of future fossil fuel production that Hook and Tang (2013) think are improbable. While fossil fuel combustion currently causes a large part of anthropogenic greenhouse gas emissions, these emissions are linked to fossil fuel production and will decrease as we begin to run out of these resources. There is a multitude of different scenarios that predict future fossil fuel emission and they range hugely in their predictions. The IPCC uses a set of six scenarios called the Special Report of Emission Scenarios (SRES), which are an input for many of their aggregated climate models and influence their conclusions. Hook and Tang question the accuracy of these SRES and aim to review the assumptions that the scenarios make about fossil fuel availability. Continue reading

Way More Methane than EPA Thinks, Maybe

by Emil Morhardt

The amount of the powerful greenhouse gas, methane (natural gas) released into the atmosphere by farmers and gas and oil companies is substantially underestimated by the USEPA according to a team led by Scott Miller, a Harvard Ph.D. student, published late last year in the Proceedings of the National Academy of Sciences. The previously unaccounted sources are ruminants, manure, and fossil fuel extraction and processing in the South-Central US, traced back to their sources from fixed towers and aircraft-based methane sensors using the Stochastic Time-Inverted Lagrangian Transport model (STILT). On the other hand, Hristov et al.(2014), in response to the Miller et al. paper, calculated cattle methane releases from the ground up  based on the number of cattle in the US and thought that the EPA had it right in the first place. So we have a calculation based on numbers of cattle competing with empirical data from the methane sensors processed through an interesting atmospheric model. This type of atmospheric modeling–tracing airborne chemicals back to their source–is what NASA is about to use with the data from its newly launched (July 2, 2014) Orbiting Carbon Observatory, OCO-2, except that the observatory will detect CO2 rather than methane. No public data from it are available as yet, but since methane oxidizes to CO2 in the atmosphere, it is possible that the satellite will soon confirm the sources of the methane. You can find out about the OCO-2 instrument here.

Miller, S.M., Wofsy, S.C., Michalak, A.M., Kort, E.A., Andrews, A.E., Biraud, S.C., Dlugokencky, E.J., Eluszkiewicz, J., Fischer, M.L., Janssens-Maenhout, G., 2013. Anthropogenic emissions of methane in the United States. Proceedings of the National Academy of Sciences 110, 20018-20022.

Hristov, A.N., Johnson, K.A., Kebreab, E., 2014. Livestock methane emissions in the United States. Proceedings of the National Academy of Sciences 111, E1320-E1320.

Please let me know if you are aware of new papers that should be written about by the Climate Vulture


Allowable Carbon Emissions Lowered by Multiple Climate Targets

by Makari Krause

Anthropogenic carbon emissions have been a large factor in climate change since the start of the industrial revolution. Scientists have become increasingly concerned with warming and other effects associated with the release of carbon into the atmosphere. Currently, most world governments have set a target that limits warming to two degrees Celsius since preindustrial times. With this target in place policies are then enacted to limit carbon emissions and hopefully to mitigate anthropogenic effects on earth’s climate. Steinacher et al. (2013) set out to show that setting a target temperature is not sufficient to control many other effects of climate change such as sea level rise and ocean acidification that also result from anthropogenic carbon emissions. They find that when targets are set for these other factors, the allowable carbon emissions are much lower than current targets based on temperature alone.

Steinacher, M., Joos, F., & Stocker, T. F., 2013. Allowable carbon emissions lowered by multiple climate targets. Nature 499(7457), 197–201.


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Stray Gases from Shale Gas Extraction Contaminate Drinking Water in Pennsylvania

Shale gas is an unconventional source of natural gas recently made accessible by horizontal drilling and hydraulic fracturing. Shale and other unconventional sources of natural gas have caused overall U.S. production of methane to increase 30% since 2005. Despite their increasing importance, the environmental implications of producing unconventional natural gas have not yet been studied extensively. Jackson et al. explored the possibility of stray gas contamination by testing for concentrations of methane, ethane, and propane in drinking water wells near homes in the Marcellus shale region of Pennsylvania. In general, they found higher amounts of dissolved gases in sources less than one kilometer from a natural gas well. Statistical analysis showed that distance from gas wells was a more significant factor for raised levels of natural gas than other potential sources of contamination. Closer analysis into the chemistry of the samples showed that at least some of the natural gases present in drinking water wells came from a thermogenic source, which includes gas wells. The authors suggest that the stray gases could be due to wells with faulty steel casings or cement sealing.—Shannon Julius
                  Jackson, R.B., Vengosh, A., Darrah, T.H., Warner, N.R., Down, A., Poreda, R.J., Osborn, S.G., Zhao, K., Karr, J.D., 2013. Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction. Proceedings of the National Academy of Sciences 110, 11250-11255

                  Jackson et al. sampled 81 drinking water wells and combined their results with information from 60 previously-collected samples. They measured the concentrations of dissolved methane, ethane, and propane in the water samples and the distance to the nearest gas well from each sample. Other possible sources of natural gas contamination—valley bottom streams and the Appalachian Structural Front—were ruled out using multiple regression analysis, linear regression, and Pearson and Spearman coefficients. In addition, the authors tested to see if the gas came from biogenic sources, i.e. produced by microorganisms, or from thermogenic sources, i.e. with a potential connection to shale gas production. Indicators of thermogenic gas include the presence of ethane or propane, certain isotopic signatures in methane (δ13C-CH4), and the ratio of helium isotope (4He) to methane.
                  The study found dissolved methane at 115 of 141 homes (82%), ethane at 40 of 133 homes (30%), and propane at 10 of 133 homes (8%). Methane had a far higher average than other natural gases in all cases, but homes within one kilometer of a natural gas well had 6 times the amount of methane as homes farther away. The 12 highest concentrations of methane were above the U.S. Department of Interior level for hazard mitigation, and 11 of  those houses were within one kilometer of a gas well. In addition, homes within one kilometer of a gas well had 23 times the amount of ethane as homes farther away, and propane was only detected at homes within one kilometer of a gas well. Ethane and propane only derive from thermogentic sources, so their presence is evidence that the natural gas contamination is likely from a gas well.
                  Another way to determine if gas is from a thermogenic source is to look at the isotopic signature. Yet again the strongest evidence for thermogenic sources (the most δ13C-CH4 signatures greater than –40‰) were within one kilometer from natural gas wells. There is also a trend of shale gas in which isotopes (δ13C) of methane become heavier than those of ethane, though in other cases it is the reverse. Six out of 11 houses where sampling was possible showed this shale gas trend, indicating that those gas samples came from shale gas production.
                  The helium isotope 4He is a component of thermogenic natural gas. The ratio of this isotope to methane (4He to CH4) in the dataset was fairly consistent, except for the points with elevated levels of methane. These had a ratio of 4He to CH4 that was consistant with Marcellus production gases, somewhat lower than normal drinking water levels.
                  The authors contend that poor well construction led to this contamination of drinking water. In particular, stray gases could have escaped through faulty protective steel casings or from imperfections in the cement sealer between the casings and rock outside the well. Faulty steel casings would lead to gas from inside the well leaking out to the surroundings, followed by metals, fracking fluids, or other evidence of gas extraction. Faulty cement would lead to any gas in the spaces around the well to escape upwards into drinking water, meaning the gases would not be easily identifiable with the well itself.

                  The authors would like to see further research to understand more about how drinking water near the Marcellus shale gas production area compares to drinking water near other shale gas sources. They also suggest gathering predrilling data, even making detailed studies of water quality before, during, and after drilling and hydraulic fracturing.