Humanity may generate more than 11 million tons of solid waste daily by the end of this century, barring significant reductions in population growth and material consumption, according to experts.
That mind-boggling large heap of trash expected by century end represents a three-fold increase in the amount of stuff people throw away today. In 1900, the world's 220 million urban residents tossed out fewer than 330,000 tons of trash daily, such as broken household items, packaging and food waste. That figure grew to 3.3 million tons of trash per day by 2000, according to an article published today in Nature.
Though some affluent countries have already hit their "peak" waste production, and are in the process of reducing how much waste they generate daily, the trash will pile up particularly high in the world's fast-urbanizing countries, said Daniel Hoornweg, an associate professor of energy systems at the University of Ontario in Oshawa, Canada, and the Nature article's lead author. The article describes projections of when various regions of the world will hit so-called "peak waste" under three scenarios of economic development.
Peak waste
Under the business-as-usual scenario, global peak waste occurs sometime after 2100, but "with lower populations, denser, more resource-efficient cities and less consumption (along with higher affluence), the peak could come forward to 2075 and reduce in intensity by more than 25 percent. This would save around (2.8 million tons) per day," he and colleagues write.
Waste peaks with higher affluence in part because people stop spending as much money on physical stuff and more on experiences, such as tickets to sporting events or a night out at the theater. In fact, across much of the developed world, peak waste is already in the review mirror.
"Where all the (new) waste is coming from is the cities in those countries that are catching up to us in terms of affluence," Hoornweg told NBC News. "Right now the locus of solid waste growth is really China and East Asia." Waste growth there may stabilize around mid-century, then pick up in India and accelerate in sub-Saharan Africa toward the end of the century.
All this trash has already created a "waste crisis," said Antonis Mavropoulos, chair of the technical and scientific committee for the International Solid Waste Association (ISWA), an organization that advocates for the development of sustainable waste management services.
"According to ISWA's assessment, more than 50 percent of the Earth's population does not have access to the most elementary waste management service ... protecting at least human health from waste-related pathogens," he told NBC News in an email. Campaigns focused on food waste prevention, in particular, he added, could help prevent the "expected rapid increase in waste generation."
Visible lifestyle
Hoornweg and colleagues define generated waste as anything taken to the curb such as junked appliances as well as cardboard boxes, beer bottles and soda cans for recycling and food scraps for composting. "It is the part of our lifestyle that is the most visible, but it is an incredibly powerful proxy for what is going on upstream in terms of our life," Hoornweg said.
It is correlated, for example, with the amount of coal burned to power factories, forests chopped to make cardboard packaging, and water polluted with the pesticides and nitrogen used to grow food. These activities, in turn, are related to the amount of greenhouse gases released to the atmosphere.
On the flipside, a reduction in waste reflects a reduction in energy consumption, greenhouse gas emissions, and water pollution. "This is one of those win-win … well I don't know how many wins in a row, but quite a few," Hoornweg noted.
And the best way to get to that multiple win is education, especially of women. "As you educate young girls, then the size of the family drops very quickly and you actually increase the quality of life," he said. "People stop having lots of children when they have confidence that in their senior years, they will be taken care of."
Other efforts at waste reduction such as zero-waste to landfill initiatives popular in the U.S. and Europe is "incredibly important" and "will stem the tide to some extent," he said, "but the tide is still coming because it is mainly a function of urban growth."
In addition to Hoornweg, co-authors of the Nature article include Perinaz Bhada-Tata, a solid waste consultant in Dubai, United Arab Emirates, and Chris Kennedy, a professor of civil engineering at the University of Toronto, Canada.
John Roach is a contributing writer for NBC News. To learn more about him, visit his website.
