Among the trends that trouble experts contemplating the future of solid waste: People create much more trash when they move to cities and when they become wealthier. (LEON NEAL/AGENCE FRANCE-PRESSE VIA GETTY IMAGES)

If you’re someone who cares about the environment, your first and foremost concern is probably climate change. After that, you might worry about such things as radioactive contamination, collapsing honeybee colonies and endangered ecosystems.

But a number of researchers 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 2025, going from 3.5 million tons to 6 million tons — per day. And we likely won’t hit peak garbage — the moment when our global trash production hits its highest rate, then levels off — until after 2100, when we will produce 11 million tons of trash per day, according to the projection.

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

Even if we sealed all our waste in sanitary landfills, 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 University of Ontario professor Daniel Hoornweg, one of the authors of the World Bank report and a co-author of an article on peak garbage published last month in the journal 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 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 on projections of population growth along with established trends in waste. Among them: 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).

Developing countries’ issues

Historical data indicate 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 he can produce.

In the rest of the world, however, the number of people moving to cities and consuming more is projected to surge over the coming century. And even as the resulting waste production levels off in East Asia around 2075, it will be offset by continuing increases in growing urban areas of South Asia and sub-Saharan Africa, the authors of the Nature article note.

Assuming that current demographic and waste production trends continue, waste accumulation will peak sometime after 2100. Only with a smaller, wealthier world population and consumption behaviors that are more environmentally friendly would peak garbage occur sooner, during this century.

How can we address the consumption problem? One of the main things to consider is that it’s largely driven by people in the developing world moving to cities and improving their standard of living, both signs of economic progress. But even if these demographic shifts continue, the projected rates of garbage growth aren’t entirely inevitable. There are also cultural and policy dimensions to waste production.

For instance, the average person in Japan creates about one-third less trash than an American, even though the two countries have similar levels of GDP per person. This is partly because of Japan’s higher-density living arrangements and higher prices for imported goods. But also, trash in many Japanese municipalities must be disposed of in clear bags (which reveal who isn’t bothering to recycle) and recyclables are routinely sorted into dozens of categories. Such policies are driven by the limited amount of space for landfills in the small country.

Creating similar incentives to produce less waste in other countries could be a way of tackling the problem. But Hoornweg and his co-authors argue in their article that accelerating increases in education and economic development in the developing world, especially in Africa, might be even more important. That would probably cause urban population growth — and also the amount of trash produced per capita — to level off sooner.

Because garbage can be a proxy for all other environmental issues, a surge in the global rate of trash production is a particularly bad idea. “The planet is having enough trouble handling the cumulative impacts that we’re subjecting it to today,” Hoornweg says. “So with this projection, we’re basically looking at tripling the total amount of stress that we’re putting the planet under.”