This Earth Day, as always, you are going to hear a great deal about the importance of protecting the planet — and about how you can do your part. You might, for instance, adopt one of a number of what some have called “Earth Day resolutions,” such as pledging to walk to work more, or finally program your thermostat — or eat less meat.

But there’s a problem. There are reasons to think that Earth Day, as influential as it is in the short term, might not be enough to instill lasting, long-term green behaviors in most people. The problem isn’t the day itself, it’s humans — how they lapse back to old habits and often fail to keep even the most earnest of resolutions.

Earth Day was created in 1970 by Sen. Gaylord Nelson (D-Wis.), in a time of heady environmental rallying that also lead to the creation of the Environmental Protection Agency and the historic passage of laws like the Clean Air Act. But that was before the modern behavioral science revolution in how we think about human energy use and conservation — and how hard it can be to get us to overcome habits, status quo biases and other foibles.

Earth Day is great for focusing initial attention, explains Elke Weber, a behavioral scientist at Columbia University who focuses on the environment and energy behavior. But the goal, she says, should be to use days like this “as a way of getting people’s attention, which they’re more likely to do if it’s one day, but then leverage them, in getting them to commit to something they can sustain over the year.”

But that’s tough, humans being humans.

Here’s just one reason to wonder about people’s professed intentions to adopt greener habits or lifestyles. Recent research suggests that even if people do adopt new green behaviors, they may also hold “compensatory green beliefs.” This means thinking that if they do one environmentally friendly thing — like, say, not driving to work — then it’s okay to lapse in another realm like, say, taking a lot of plane flights.

A recent study in Britain, for instance, found that 16 percent of people agreed with the statement, “Not driving a car compensates for flying on holiday.” But of course, if everyone thinks this way, then green behaviors will be offset by less green ones, and overall progress will be greatly slowed or even offset entirely.

Another hurdle is the research on what people actually do after publicly pledging or promising (to themselves, or to others) to engage in some behavioral change. “There’s a lot of evidence on the difference between people making public pledge to do things, and then privately following up on them,” says Craig Parks, a social psychologist at Washington State University.

Indeed, there’s experimental evidence suggesting that even when people know they need to cut back on using up resources, they only do so for a short period of time.

In one study, Parks and colleagues had students play a game in which they managed a resource, and were told to “accumulate as many points as possible while still maintaining the resource over the long-run.” Each round, individual players “harvested” a certain number of points from the shared resource, and then were warned at the thirteenth round, “This is a warning that you are dangerously close to depleting your resource. Please make your next choice.”

The study found that players promptly stopped depleting the resource as much, but also that that conservation behavior only lasted a few rounds in the game — and then players were pretty much back to their old habits, seeming to assume the problem had gone away.

“They would go into conservation mode for two or three decision rounds, and then would go back to their own behavior,” explains Parks. “They often would run the thing into the ground.”

So how do you change habits?

The trick seems to be co-opting people’s own psychology to “nudge” them in green directions. For water and energy conservation alike, for instance, research suggests that the power of peer pressure — by giving people reports about their water or energy use at home, and how it compares with that of their neighbors — can lead to significant cutbacks in usage.

That’s because much like habits themselves, social comparisons are an absolutely fundamental aspect of who we are.

Columbia’s Weber also focuses heavily on the importance of fixing “defaults” — the way many of our industrial and energy systems are set up, which is typically in such a way as to make a non-green choice easier to make than a green one. This empowers status quo biases that favor habits over change.

As I reported after interviewing her for a story about bringing about behavioral change in energy use in the military:

“Every few months you get a letter from your utility saying, ‘Do you want to switch to green electricity?’ ” says Columbia University’s Weber, “and most people just throw these in the garbage.” But what if the letter instead informed you that you were being opted in to cleaner energy, unless you actually bothered to fill out the card saying “no thanks” and mail it back in?

With climate change in particular, there’s also the feeling that the problem is massive, that nobody can really affect it, which tends to dissuade people from taking actions, says Weber. “If on Earth Day you told them what they could do in their own domain, I think that would be a really good use of that day,” she says.

To that end, here’s a chart from University of California-Berkeley PhD candidate Joseph Kantenbacher showing a large range of human activities, classified by how much energy they use per unit of time:

Earth Day is a very good day for getting us started on conservation. But we’ve got to understand people to make the spirit last all year.