**5.3 Natural gas**

The situation for natural gas, the primary energy and hydrogen source for creation of synthetic nitrogen fertilizer, is more promising but still uncertain. Technological developments of hydraulic fracturing (fracking) and horizontal drilling have begun to unlock oil and natural gas from extensive shale formations. This has led to sharp increases in estimates of U.S. natural gas reserves (EIA, 2011c), as well as large increases in drilling activity in formations such as the Barnett Shale in Texas and the Marcellus Shale in Pennsylvania. The broad distribution of comparable shale formations around the world suggests that similar initiatives will lead to an abundance of natural gas potentially lasting many decades into the future. However, doubt has been cast on the most optimistic projections.

First, fracking is controversial because of its potential environmental impacts. The process involves injection into the target formation at high pressure of a large volume of water mixed with sand and a brew of chemicals, some of them toxic. The major concern is the potential for contamination of surface or groundwater. This could occur through failure of well linings intended to isolate deep wells from shallower geological strata, though spills of concentrated fracking fluids, or through inadequate treatment of fracking fluids released into local streams. An additional concern is the potential for resource conflict associated with the sheer volume of water required for fracking. As a result of such concerns, France has banned the technology (Patel, 2011). In the United States, the potential impact on

lower quality resources will advance the timing of Peak Coal into the relatively near future (one to two decades, not one to two centuries). Independently, Rutledge (2011) has analyzed the patterns of coal development and concluded that actual developed reserves typically are about ¼ of the early reserve estimates of the geological resource. He concludes that the world will consume 90% of producible coal by 2070. Although he refrains from discussing peak production, his analysis again points to a time no more than a few decades into the future. Patzek & Croft (2010) project a peak already in 2011, with a production decline to

Glustrom (2009) provides a bottom-up analysis of coal reserves, focusing primarily on the western United States. Analyzing the production potential of individual mines, especially in the Powder River Basin of Wyoming and Montana, which accounts for about 40% of U.S. coal production, she finds that extant surface mines on the basin perimieter have 10-20 year production horizons. Expanding production by development of new surface mines faces regulatory and infrastructure obstacles; mining of deeper deposits faces these, as well as additional energetic and economic costs. She does not analyze the coal resources of other countries in detail, but citing Rutledge and one of the same studies as Heinberg, she infers that the issue is global. Although the existence of vast coal resources is clear, the energetic and economic viability of production from lower and lower quality formations in less and

Consequently, expanded reliance on coal-powered electricity to meet agricultural needs faces economic challenges. These challenges apply also to post-farm components of the food system, implying an overall rise in household food expenditures, especially in developed countries where these components account for a much larger share of food

The situation for natural gas, the primary energy and hydrogen source for creation of synthetic nitrogen fertilizer, is more promising but still uncertain. Technological developments of hydraulic fracturing (fracking) and horizontal drilling have begun to unlock oil and natural gas from extensive shale formations. This has led to sharp increases in estimates of U.S. natural gas reserves (EIA, 2011c), as well as large increases in drilling activity in formations such as the Barnett Shale in Texas and the Marcellus Shale in Pennsylvania. The broad distribution of comparable shale formations around the world suggests that similar initiatives will lead to an abundance of natural gas potentially lasting many decades into the future. However, doubt

First, fracking is controversial because of its potential environmental impacts. The process involves injection into the target formation at high pressure of a large volume of water mixed with sand and a brew of chemicals, some of them toxic. The major concern is the potential for contamination of surface or groundwater. This could occur through failure of well linings intended to isolate deep wells from shallower geological strata, though spills of concentrated fracking fluids, or through inadequate treatment of fracking fluids released into local streams. An additional concern is the potential for resource conflict associated with the sheer volume of water required for fracking. As a result of such concerns, France has banned the technology (Patel, 2011). In the United States, the potential impact on

less accessible places renders increasing rates of production problematical.

50% of the peak by 2037.

system energy.

**5.3 Natural gas** 

has been cast on the most optimistic projections.

drinking water prompted a Congressional mandate to the Environmental Protection Agency (EPA) to study the issue. Preliminary results are due in 2012 and a final report in 2014 (EPA, 2011, p. *x*). Fracking has been widely used for production of coalbed methane in the western U.S. and the potential energy resource is exceedingly valuable, so that the practice will continue in most countries, possibly under greater regulatory scrutiny.

Second, questions have surfaced concerning the magnitude and potential cost of shale gas production, as reviewed by Hughes (2011a). Evidence exists that shale gas wells deplete rapidly, so that the ulimtate resource is smaller than conventional projections (Figure 10). Morever, the technology-intensive drilling process (even apart from environmental concerns) requires elevated prices to be profitable—higher than present prices and higher than EIA projections for a decade or more. Consequently, either shale gas resources will prove to be smaller than early optimistic estimates or prices will rise so that shale gas can profitably accommodate growing demand.

Finally, doubt has arisen over the life-cycle carbon emissions of shale gas, particularly compared to coal, and therefore over the potential of natural gas to reduce emissions by displacing coal and thus to serve as bridge fuel in a transition to a renewable energy economy. Hone (2011) reviews this issue and Hughes (2011a) also compares two discordant shale gas-coal comparison studies. Shale gas probably would reduce total emissions, especially as best-practices evolve to minimize fugitive emissions (methane, the principal component of natural gas has roughly 20 times the heat-trapping effect as CO2), but perhaps not by the 50% projected by the most optimistic estimates.

Fig. 10. Shale gas drilling rates (blue) and production (red)(Hughes 2011a). Solid lines represent historical data. Red dashed line and blue dotted line represent Hughes' alternatives to EIA projections.

Fossil Fuel and Food Security 291

The great success of the Green Revolution in expanding food production faster than population during the second half of the 20th century depended on multiple developments in plant genetics, expanded use of synthetic fertilizer, increased irrigation, mechanization, petroleum-based herbicides and pesticides, and policies at the national and international levels (Smedshaug, 2010, pp. 219-222). Many of the innovations depended on low energy costs, especially for oil, that are unrepeatable. Particularly in developed countries, cheap energy has led to widespread intensification, indeed, industrialization of agriculture, with capital and fossil fuel inputs producing very high yields (e.g., in kg/ha) with very low inputs of human labor (Pimentel & Pimentel, 2008, Chapter 10). A social consequence of this has been disruption of agricultural communities and migration to cities where

For all its success, industrial agriculture is unsustainable (Tilman, 1998; Kimbrell, 2002), owing to its diverse negative effects on the environment and on social systems, which

Reduction of agricultural biodiversity through monoculture plantings of a small

Health impacts of agricultural chemicals, antibiotic residues in human food, and poor

All of these impacts threaten the stability of global food production, and hence threaten food security. In addition, for all its productivity, industrial agriculture has failed to provide adequate food access to roughly 15% of the global population. Consequently, discussions of food security increasingly stress the need for agricultural systems to move to methods that can be sustained over generations (Pimentel & Pimentel, 2008, Chapter 23; Science, 2011; Smedshaug, 2010, pp. 222-225; Smil, 2010; Worldwatch, 2011). The coupling of food prices to

The following subsections highlight proposed approaches to sustainable agriculture. Owing to the complexity of the global agricultural system, including huge differences between developed and developing countries, as well as linkages to economic and social policy, it can only provide a sampling of available information. Topics include agroecology; organic cultivation; crop breeding, including both genetically modified organisms (GMOs) and

The central theme of evolving global agriculture in the 21st century is "sustainable intensification," which FAO (2011c, Chapter 1) has defined as "producing more from the

perennial crops; competition with biofuels; and proposed broad strategies.

Reduction of wild biodiversity through habitat destruction and pesticide poisoning

unemployment has been a common outcome (Berry, 2010).

Contamination of groundwater with pesticide runoff

 Soil erosion far in excess of natural replenishment Increased incidence of crop and animal diseases Pollution from concentrated animal wastes

Opportunity costs of public agricultural subsidies

rising prices of fossil fuels compounds this need.

 Eutrophication of waterways from runoff of excessive nutrients Reduction of soil fertility through loss of soil organic matter

include the following.

number of crop cultivars

Release of greenhouse gases

diets

**6.1 Agroecology** 

Disruption of agricultural communities

No one doubts the existence of a vast geological shale gas resource, but, as for coal, conversion to producible reserves depends as much on energetics and economics as on technology. Such considerations about shale gas production will determine the ultimate magnitude of global natural gas production. Given the importance of natural gas for synthesis of nitrogen fertilizer, the evolution of shale gas production in the coming decades will have a direct impact on the cost of conventional efforts to maintain soil fertility.

In this regard and as mentioned above, the dependence of global agriculture on mined phosphorus also is a relevant concern. To the extent that fossil fuel availability contributes to the cost of mining, it will impact the price of this other critical soil nutrient.
