critical thinking

Holistic Assessment of Critical Thinking

Essay Directions:

Read the passages below and write an essay that addresses the following:

· What is the position in each passage?

· What evidence or reasons are given in support of each position?

· Which position is more convincing and why?

Do no additional research on the topics other than using a dictionary. [NEW]

The Controversy: Does fracking contribute to global warming?

Passage 1. Pro: from "Fracking Contributes to Global Warming" by Louis W. Allstadt

The fracking that's going on right now is the real wake-up call on just what extreme lengths are required to pull oil or gas out of the ground now that most of the conventional reservoirs have been exploited—at least those that are easy to access.

First of all you have to look at what is conventional oil and gas. That was pretty much anything that was produced until around 2000. It's basically a process of drilling down through a cap rock, an impervious rock that has trapped oil and gas beneath it. And once you're into that reservoir—which is really not a void, it’s porous rock—the natural pressure of the gas will push up the gas and oil.

Now what's happened is that the prospect of finding more of those conventional reservoirs, particularly on land and in the places that have been heavily explored like the US and Europe and the Middle East just is very, very small. And the companies have pretty much acknowledged that. All of them talk about the need to go to either nonconventional shale or tight sand drilling or to go into deeper and deeper waters or to go into really hostile Arctic regions and possibly Antarctic regions.

Both the horizontal drilling and fracturing have been around for a long time. The industry will tell you this over and over again—they've been around for 60 years, things like that. That is correct. What's different is the volume of fracking fluids and the volume of flowback that occurs in these wells. It is 50 to 100 times more than what was used in the conventional wells.

The other [difference] is that the rock above the target zone is not necessarily impervious the way it was in the conventional wells. And to me that last point is at least as big as the volume. The industry will tell you that the mile or two between the zone that's being fracked is not going to let anything come up.

But there are already cases where the methane gas has made it up into the aquifers and atmosphere. Sometimes through old well bores, sometimes through natural fissures in the rock. What we don't know is just how much gas is going to come up over time. It's a point most people haven't gotten. It's not just what's happening today. We're opening up channels for the gas to creep up to the surface and into the atmosphere. And methane is a much more potent greenhouse gas in the short term—less than 100 years—than carbon dioxide.

Source Citation

Allstadt, Louis W. "Fracking Contributes to Global Warming." Natural Gas, edited by Dedria Bryfonski, Greenhaven Press, 2015. Opposing Viewpoints. Opposing Viewpoints in Context, Accessed 12 Dec. 2016. Originally published as "Former Mobil VP Warns of Fracking and Climate Change," Truthout.org, 19 July 2013.

Passage 2. Con: from "Fracking Does Not Contribute to Global Warming" by Coral Davenport

A new study in the Proceedings of the National Academy of Sciences concludes that hydraulic fracturing—the controversial technique behind the nation's recent oil and gas boom—doesn't appear to contribute significantly to global warming, as many environmental groups have warned.

It's great news for oil and gas companies such as ExxonMobil, Shell, and Chevron, which have relied on breakthroughs in so-called fracking technology to cheaply unlock vast new reserves of domestic oil and natural gas that had been trapped underground in shale-rock formations.

"It's very good news," said Richard Keil, a spokesman for ExxonMobil, of the study. "This is a groundbreaking survey. It's the most extensive one that's been done yet, and it serves to add important new evidence that hydraulic fracturing does not contribute to climate change—it does not contribute methane emissions at levels higher than those set by the Environmental Protection Agency [EPA]."

The study concluded that the majority of hydraulically fractured natural gas wells have surface equipment that reduces on-the-ground methane emissions by 99 percent, although it also found that elsewhere on fracking rigs, some valves do allow methane to escape at levels 30 percent higher than those set by EPA. Overall, however, the study concludes that total methane emissions from fracking are about 10 percent lower than levels set by EPA.

The $2.3 million study was conducted by scientists at the University of Texas, with funding provided by nine energy companies, including ExxonMobil, and one environmental group, the Environmental Defense Fund. A spokesman for the University of Texas said that while the companies contributed money to the study, they had no input on the research or results, which were subject to independent peer review before being published in the Proceedings of the National Academy of Sciences, one of the nation's most prestigious scientific journals.

University of Texas researchers say their yearlong study, which involved measuring methane emissions from 190 natural gas production sites in the Gulf coast, mid-continent, Rocky Mountains, and Appalachia, is far more comprehensive than [other studies], which relied on existing data rather than new fieldwork.

Source Citation

Davenport, Coral. "Fracking Does Not Contribute to Global Warming." Natural Gas, edited by Dedria Bryfonski, Greenhaven Press, 2015. Opposing Viewpoints. Opposing Viewpoints in Context, Accessed 12 Dec. 2016. Originally published as "New Study Says Fracking Doesn't Contribute to Global Warming," National Journal, 16 Sept. 2013.