Can We Put a Brake on Homely Emissions?

Originally published at

Looking for the key to getting a jump on cutting U.S. greenhouse gas emissions? It may be in our homes.

As efforts drag on to get national and international carbon policies in place, researchers and policy makers have turned their attention to less ambitious measures. Expanding the Montreal Protocol to address the heat-trapping properties of replacements for ozone-depleters or cutting emissions of heat-trapping soot or black carbon are two ideas being floated.

A new paper by Tom Dietz of Michigan State University and co-authors in the Proceedings of the National Academy of Sciences reminds us that we should not forget efforts closer to home.

An astounding 38 percent of all U.S. greenhouse gas emissions come from households. Would it surprise you to learn that relatively simple changes in those households can pare down our emissions?

Potential Emissions Savings from Reducing Personal Energy Waste Nothing to Sneeze At

The authors estimate that through policies that target personal and household energy waste we could trim about 123 million metric tons of carbon emissions per year or about 7.4 percent from our national budget.

That's nothing to sneeze at.

A 123-million ton cut in annual emissions would not get us anywhere near the 80 percent reduction called for in proposed climate legislation like Waxman-Markey. But it's a considerable amount. It's more than the total fossil fuel emissions from Mexico, France or South Africa. Domestically, it would be equivalent to eliminating all emissions from petroleum refining, as well as iron, steel, and aluminum manufacturing. And a 7.4 percent emissions cut would get us almost halfway to the 2020 emissions reduction target in the Waxman-Markey climate bill passed by the House -- not a bad first step and one with little or no cost.

The Behavioral Wedge

In a seminal paper from 2004 Princeton scientists Steve Pacala and Rob Socolow referred to various types of technologies that could be used to lower emissions -- like solar and wind or so-called clean coal -- as wedges, with each wedge contributing to the pie of emissions cuts needed to achieve a given climate target.

Dietz et al. in deference to Pacala and Socolow call their emissions reduction efforts the "behavioral wedge" because, just as you'd think, they rely on behavioral rather than technological changes. Within the behavioral wedge, Dietz et al. outline 17 broad actions related to households and non-business travel. They range from familiar ones such as weatherizing the home, changing HVAC filters, and car-pooling to more retro things like line-drying clothes. (Hey, why not hang 'em on a line? Dry clothes are dry clothes.)

Business as Usual on the Home Front

The authors argue that changing behavior to take some of these actions would not mean a significant drop in what they call "household well-being." Whether or not that's the case for you depends on how you view your well-being and what goes into it. But it'd be hard to argue that regularly changing your HVAC filter or even hanging your clothes on a line would represent a major loss in your well-being.

The authors used a two-step approach to estimate the potential emissions reduction.

  1. For each action, they first calculated the amount of emissions savings from 100 percent adoption of the action.
  2. Then, using empirical data on the effectiveness of various existing interventions designed to change behavior (some of which related to energy consumption), they estimated the likely adoption rate for each action.

Not surprisingly, they found that adoption rates varied considerably, from a high of 90 percent for weatherization to a low of only 15 percent for car-pooling.

Combining the total emissions savings available for each action and its adoption rate, Dietz and co-authors estimated the overall emissions reductions that could be achieved from a coherent, concerted effort to get Americans to waste energy less: a 7.4 percent overall reduction in U.S. emissions.

So what are those behavioral interventions?

Basically they are public policies designed to encourage and motivate people to adopt energy-saving devices and practices. These would include a multifaceted campaign providing consumers with relevant information as well as financial assistance and subsidies where appropriate. They would also no doubt involve a good deal of PR to raise public awareness and create social momentum toward the desired behavior.

Sounds like a reasonable idea to me. And there is a precedent. Back during WWII, the government ran a war bonds campaign. They billed it as "The Greatest Investment on Earth." I can just see the new campaign: Be Efficient -- The Greatest Investment for the Earth ... and It Won't Cost You Anything.