Category Archives: Global Warming

Electricity Emissions Factors by Region, Part 1: Background and the Western Region

Part the First: Brief Background on Emissions Factors

Electricity generation accounts for almost one-third of US territorial greenhouse gas emissions, and the average US residence consumes just under 11,000 kilowatt-hours (kWh) electricity per year (in addition to other fuels, such as natural gas).  Thus, it is essential to understand the impact of electricity use, and especially how changes in use at the household level will affect emissions.

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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.”

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From 17,000 kWh/year to less than zero: my experience with energy-efficiency and rooftop solar in Mesa, AZ

I wrote several hundred pages of a book that amounted to exhorting people to alter their own habits of residential energy consumption (turn down the heat, you rogues!), as well as upgrade their built environment  (e.g. insulate the attic) and appliances, or even, *gasp*, add solar to their roofs.  All this because the numbers, at least in the abstract, showed that such banal acts of conservation (not counting solar) can reduce the carbon footprint of residential energy use by at least 30-50%, from a baseline average of about 12 metric tonnes (1 tonne = 1 metric ton) of CO$_2$-equivalent (CO$_2$e).  But a demonstration of how, over the course of roughly 5 years, the net energy use in my house actually fell progressively from around 17,000 kWh of electricity per year down to less than zero (net) seems in order.

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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.

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The Inaugural Post

Welcome to EnvironMath!  Hopefully this will become a useful record of (sometimes) mathematically oriented reviews of topics in the environment (and perhaps other areas).  To get started (and to shamelessly self-promote), I’m adding multiple (free) excerpts from my new book, A Fair Share: Doing the Math on Individual Consumption and Global Warming.