Category Archives: Land Use

Whence Coal, Oil, and Natural Gas?

A primer on the origin, extraction, and emissions of everyone’s favorite fossil fuels

Three major forms of fossil energy together provide almost all the world’s energy: coal, oil (and the derived petroleum fuels), and natural gas. Moreover, humanity’s insatiable appetite for these fuels is the major driver of climate change. Therefore, it is essential to understand the fundamentals of these fuels: Where do they come from, what are their properties, and how do we extract them. Furthermore, it is generally understood that natural gas is the “cleanest” of the fossil fuels, while coal is the dirtiest. Again, we must ask why, and provide at least a basic answer. The purpose of this article is to answer (at least broadly) these questions, and to make the reader familiar with some key terms and concepts. In brief, the takeaways are:

  • All fossil fuels derive from organic matter buried at great depths and processed under pressure.
  • Oil and gas are produced by the same basic geologic processes, and are often present in the same wells/fields. Conventional oil/gas is formed when these hydrocarbons seep from low permeability source shales to collect in “traps,” where they can be pumped by conventional methods.
  • Unconventional oil/gas extraction via “fracking” involves drilling into and breaking up source shales directly.
  • Coal in the US is most commonly mined via surface mines, especially mountain top removal with valley fill, where whole mountains are blasted away to access coal seams.
  • Fossil fuels are mainly a mix of molecules with carbon (C) and hydrogen (H) bonds. Burning oxidizes these molecules to water and carbon dioxide, releasing heat along the way. The more C-H bonds, vs. C-C bonds, the more energy is released per atom of C, and thus the less CO₂ per heat energy released.
  • Natural gas, as CH₄, has the most C-H bonds of any fossil fuel (it is the most “reduced”), and burns the cleanest. Coal is the least reduced fossil fuel, and burns dirtiest.

Continue reading

Oblivion by any other name: “Biological annihilation” and “defaunation” in the “Anthropocene”

Everything that needs to be said has already been said. But since no one was listening, everything must be said again.

André Gide

I too am reduced to repeating what must be said, and given this nascent blog’s readership, it seems rather likely that it will need saying again.  To wit, George Monbiot recently discussed, in a melancholy but extremely important article (see also the version in The Guardian), the vanishing of so much nature and wild life before his own eyes, in his own lifetime.  It is not mere false nostalgia, and he cites much published work that documents the astonishingly rapid and ongoing global loss of animal life, a process that has been variously (and by respectable scientists, no less!) termed “defaunation” in the “Anthropocene” and, more recently, a “biological annihilation.”

Continue reading

Paper of the Day: Poore & Nemecek (2018): Reducing food’s environmental impacts…


A new analysis drawing on 570 studies with data covering 38,700 commercial farms shows dramatic variation both worldwide and within-region in the environmental impact across all major foods, but confirms that beef in particular and animal products in general are responsible for the greater part of food’s impact on earth, which adds up to 31% of global warming emissions (including non-food agriculture), and 43% of ice- and desert-free land.  Supplementary material available for free (and is very comprehensive), while the main article is for subscribers only (here).

Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science, 360(6392), 987-992.

Continue reading