If a stranger said they'd give you $5 every time you take the bus instead of driving, would you?

You're probably going to burn a couple dollars worth of gas stuck in this traffic jam anyway. Photo from iStock.

What about a quarter for every time you bring your own water bottle, instead of reaching for a disposable one?

And do you think they'd want a receipt? Photo from iStock.

It seems like every day a new celebrity, campaign, or advertisement tries to give people a new thing they can do to help save the Earth. The message is usually pretty simple: Do this thing because it's easy, or cheap, or good, or just because you should. A lot of these campaigns work, and that's great. But for every person who participates, there are plenty more who don't.

It's not that people don't want to help, it's just really hard to get people to go out of their way to change their behavior.

Maybe what we need isn't to invest in more clever calls for altruism. Maybe it's simpler than that.

What if we paid people to not do things that harm the environment?

Seema Jayachandran, a professor from Northwestern University recently tried out this concept in Uganda, where deforestation has reduced forest cover to just a fraction of what it once was.

Jayachandran and her team offered villages a small stipend to not chop down the trees near their homes. A little over two years later, the researchers found that the villages who'd received payments had less than half the deforestation compared to others nearby.

Uganda is home to over half of the world's wild mountain gorillas, who depend on the forest to survive. Photo from iStock.

This kind of program is known as payment for ecological services and has been successfully used before in places like Costa Rica and Mexico.

Similar tactics have also been explored in trying to get people to exercise more or stop smoking.

These interventions can be pretty effective and cost-effective. After all, the Earth itself is worth beaucoup bucks.

Nature isn't just here to look pretty — it provides food, shelter, jobs, and, you know, the oxygen we need to breathe. In 1997, a bunch of ecologists and economists estimated that the natural world gives us $33 trillion worth of free stuff every year.

Protecting nature has a pretty good return on investment. In terms of reducing carbon emissions, Jayachandran's experiment in Uganda returned about $2.40 of value for every dollar they put in, the Atlantic reported.

Changing human behavior is tricky and paying people to not do something might seem inelegant at first. If you think of the Earth as a business, though, a little investment in the right behaviors might actually make a lot of sense.