The amount of garbage humans throw away is rising fast and won't peak this century without transformational changes in how we use and reuse materials, write former World Bank urban development specialist Dan Hoornweg and two colleagues.
By 2100, they estimate, the growing global urban population will be producing three times as much waste as it does today. That level of waste carries serious consequences – physical and fiscal – for cities around the world.
Hoornweg and co-author Perinaz Bhada-Tata expanded on their work from the 2012 World Bank report What a Waste: A Global Review of Solid Waste Management to estimate the trajectory of solid waste growth globally and to determine when it might peak.
In the earlier report, they warned that global solid waste generation was on pace to increase 70 percent by 2025, rising from more than 3.5 million tonnes per day in 2010 to more than 6 million tonnes per day by 2025. The waste from cities alone is already enough to fill a line of trash trucks 5,000 kilometers long every day. The global cost of dealing with all that trash is rising too: from $205 billion a year in 2010 to $375 billion by 2025, with the sharpest cost increases in developing countries.
In the new article, appearing in the journal Nature, Hoornweg, Bhada-Tata, and Chris Kennedy forecast that if business continues as usual, solid waste generation rates will more than triple from today to exceed 11 million tonnes per day by 2100. Organization for Economic Cooperation and Development (OECD) countries, where waste levels are the highest today at around 1.75 million tonnes per day but populations aren’t growing as quickly and waste reduction efforts are underway, are likely to see their trash levels peak by 2050 and then start to decline, the authors write. Asia-Pacific countries won't peak until 2075. How soon Sub-Saharan Africa's waste increase peaks will determine how soon the world’s trash problem begins to decline.
The results hold serious consequences for public services, government budgets, and the space consumed by landfills. Already, Mexico City's Bordo Poniente and Shanghai's Laogang receive more than 10,000 tonnes of waste per day, and the world's more than 2,000 waste incinerators raise concerns about ash disposal and air pollution. Landfills, and uncollected waste, also contribute to climate change through the production of methane, a potent greenhouse gas.
It doesn’t have to be this way
The authors based their estimates on a "business as usual" scenario. The future doesn't have to turn out that way, they say.
