In 2013, if you’re someone who cares about the environment, your first and foremost concern is probably climate change. After that, you might worry about things like radioactive contamination, collapsing honeybee colonies and endangered ecosystems, among other contemporary environmental perils that fill recent news headlines.

But a number of researchers in the field are focused on a problem that has faded out of the news cycle: the piles of garbage that are growing around the world.

A recent World Bank report projected that the amount of solid waste generated globally will nearly double by the year 2025, going from 3.5 million tons to 6 million tons per day. But the truly concerning part is that these figures will only keep growing for the foreseeable future. We likely won’t hit peak garbage—the moment when our global trash production hits its highest rate, then levels off—until sometime after the year 2100, the projection indicates, when we produce 11 million tons of trash per day.

Why does this matter? One reason is that much of this waste isn’t handled properly: Millions of plastic fragments flooding the world’s oceans and disrupting marine ecosystems, and plenty of trash in developing countries is either burned in incinerators that generate air pollution or dumped recklessly in urban environments.

Even if we sealed all our waste in sanitary landfills, however, there’d be a much bigger problem with our growing piles of garbage—all the industrial activities and consumption that they represent. “Honestly, I don’t see waste disposal as a huge environmental problem in itself,” explains Daniel Hoornweg, one of the authors of the World Bank report and a professor at the University of Ontario, who authored an article on peak garbage published today in Nature. “But it’s the easiest way to see how the environment is being affected by our lifestyles overall.”

The quantity of garbage we generate reflects the amount of new products we buy, and therefore the energy, resources and upstream waste that are involved in producing those items. As a result, Hoornweg says, “solid waste is the canary in the coal mine. It shows how much of an impact we’re having globally, as a species, on the planet as a whole.”

This is why he and others are concerned about peak garbage and are attempting to project our trash trends decades into the future. To make such estimates, they rely upon projections of population grown along with a number of established trends in waste: People create much more trash when they move to cities (and begin consuming more packaged products) and when they become wealthier (and increase their consumption overall).

Historical data indicate, though, that a certain point, the per capita amount of garbage generated in wealthy societies tends to level off—apparently, there’s only so much a person can consume (and only so much trash they can produce). As a result, in many of the world’s wealthy countries, the average person produces slightly more than 3 pounds of solid waste per day, and that number isn’t estimated to change significantly going forward.

The amount of people moving to cities and consuming more in the rest of the world, however, is projected to surge over the coming century—and even as the resulting waste production finally levels off in East Asia around 2075, it’ll be offset by continuing increases in the growing urban areas of South Asia and Sub-Saharan Africa, the authors of the Nature article note. As a result, unless we significantly reduce the per capita waste production of wealthy city-dwellers, the world as a whole won’t hit peak garbage until sometime after 2100, when we’re creating three times as much trash as we are right now.