Greenhouse gases

Future climate forcing potentially without precedent in the last 420 million years, Gavin L. Foster, Dana L. Royer and Daniel J. Lunt, Nature Communications, 8, 14845, April 4th, 2017.

In Chapter 8, Section 8.2, in the sub-section called Radiative Forcing, an explanation of the term radiative forcing is provided. This recent communication provides a look at future climate forcing based on changes in the greenhouse gas content of the atmosphere.

Mobility and persistence of methane in groundwater in a controlled-release field experiment, Cahill, A.G. C.M. Steelman, O. Forde, O. Kuloyo, S. E. Ruff, B. Mayer, K. U. Mayer, M. Strous, M. C. Ryan, J.A. Cherry, and B.L. Parker, Nature Geoscience, 10, 289–294, (2017) doi:10.1038/ngeo2919, Published online 27 March 2017.

Chapter 8, Section 8.5 titled ‘Greenhouse gases associated with the use of fossil fuels’, has a new sub-section called ‘Hydraulic fracturing (fracking) for recovery of natural gas and petroleum’ and discusses the concerns with this extraction method. Figure 8.16 depicts the processes and the leakage of methane throughout the ‘fracked’ region. This paper further investigates the consequences of methane leakage into groundwater. The authors present results from a 72-day methane gas injection experiment conducted in a shallow, flat-lying sand aquifer. Their results reveal that although a significant fraction of methane is vented to the atmosphere, an equal portion remained in the groundwater. They go on to explain that methane migration was more lateral than anticipated due to the interference of ‘grain-scale bedding’. They also show that methane persisted in the groundwater despite active growth of methanotrophic bacteria. They conclude by suggesting that their findings demonstrate that even small amounts of released methane into nearby groundwater should be a cause for concern.

Also see the article on the Nitrogen cycle under Chapter 15

Long-term trends and opportunities for managing regional water supply and wastewater greenhouse gas emissions, Hall, M.R., J. West, B. Sherman, J. Lane, and D. de Haas, Environ. Sci. Technol. 2011, 45, 5434–5440 (Published by ACS, May 2011).

This paper provides an example of a source of greenhouse gases that we only briefly touch on in our text in Figure 8.12. Some of their data suggest that this source is beginning to rival some of the traditional energy sources. (see also Chapter 16)

Carbon: sources and sinks

A tale of two technologies: hydraulic fracturing and geologic carbon sequestration, J. A. Dammel, J. M. Bielicki, M. F. Pollak, and E. J. Wilson, Environ. Sci. Technol. 2011, 45, 5075–5076 (Published by ACS, May 2011).

Global Climate (Chapter 8) is both positively and negatively affected by large scale industrial processes. Two emerging technologies are briefly discussed in this editorial which add nicely to our discussion in Section 8.7 where we introduce carbon sequestration, and to the section on Natural Gas where we have not yet mentioned the method of hydraulic fracturing (fracking).