Cass Sunstein is the Robert Walmsley University Professor at Harvard Law School. His expertise extends to several fields of law and behavioural economics. He was administrator of the White House Office of Information and Regulatory Affairs and is the New York Times bestselling co-author of Nudge. 

 “If you want to make the environment cleaner, here’s a simple idea: make the green option the easy option. And, if you want to make it really easy, make it automatic.” 


If you want to make the environment cleaner, here’s a simple idea: make the green option the easy option. And if you want to make it really easy, make it automatic. To reduce air pollution and water pollution, to cut greenhouse gas emissions, and to save biodiversity here’s a new proposal: Make things automatically green. 

The proposal might not be familiar, but in many countries, our lives are increasingly accompanied by the equivalent of “green defaults” replacing dirtier ones. Consider motion detectors that turn out the lights when people do not appear to be in the room. In this way, motion detectors create the equivalent of an “off” default. Another example: if the default setting on office thermometers is turned down in winter, and up in summer, we should expect significant economic and environmental savings – at least if the default setting is not so uncomfortable that people will take steps to change it. 

Both policy and technology are making green defaults of this kind readily available. They work for two different reasons. First, inertia is a powerful force. People will often do nothing – and if doing nothing means doing green, that is exactly what they will do. Second, a green default is a kind of signal. It tells people what it is right to do. 

Here’s a small example: human beings use a lot of paper, and paper requires use of a large number of trees. Suppose that a private or public institution wants both to save money and to protect the environment by reducing its use of paper. A simple intervention is to alter the institution’s default printer setting from “print on a single page” to “print on front and back”. A number of years ago, Rutgers University, in the US state of New Jersey, adopted such a double-sided printing default. In the first three years of the new default, paper consumption was reportedly reduced by well over 55 million sheets, or 44%, the equivalent of 4,650 trees. Similarly impressive results were found at a large university in Sweden. 

Here’s a big example: the choice between utility suppliers. Typically, the default may not be environmentally friendly; it might be coal. To use green energy (such as solar or wind), people must seek out relevant information and choose it affirmatively. Most don’t bother, but what would be the effect of switching to a green default? The evidence is in, and it’s very clear: many more people end up with green energy. They stick with it, even if it’s a bit more expensive. As a result, the air is a lot less dirty and greenhouse gas emissions are a lot lower. 

If we want a cleaner world, we’ll need plenty of mandates. But we can make a lot of progress without them. Automatically green may not be a catchy phrase, but for institutions all over the world it is one to live by. 

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Read the Living Planet Report 2020