Rising prosperity and the increasing urbanisation of the world population could lead to a doubling in the volume of municipal solid waste (MSW) created annually by 2025, according to new research conducted by the World Watch Institute - an independent research organisation dedicated to global environmental concerns.
The researchers said that although some of this waste is recycled, the doubling of waste that current projections indicate would bring the volume of MSW from today's 1.3 billion tonnes per year to 2.6 billion tonnes - challenging environmental and public health management in the world's cities.
The report defines MSW as consisting of organic material, paper, plastic, glass, metals, and other refuse collected by municipal authorities, largely from homes, offices, institutions, and commercial establishments. The authors added that MSW is a subset of the larger universe of waste and typically does not include waste collected outside of formal municipal programs. The report also noted that MSW is measured before disposal, and data on it often include collected material that is later diverted for recycling.
According to the study, MSW tends to be generated in much higher quantities in wealthier regions of the world. Members of the Organisation for Economic Co-operation and Development (OECD), a group of 34 industrialised nations, lead the world in MSW generation, at nearly 1.6 million tonnes per day. By contrast, the report found that sub-Saharan Africa produces less than one eighth as much, some 200,000 tonnes per day.
However, the list of top 10 MSW producing countries includes four developing nations (Brazil, China, India, and Mexico) in part because of the size of their urban populations and in part because their city dwellers are prospering and adopting high-consumption lifestyles.
Unsurprisingly the U.S. leads the world in MSW output at some 621,000 tonnes per day, China is a relatively close second, at some 521,000 tonnes. Even among the top 10, however, there is a wide range of output, with the U.S. generating nearly seven times more urban refuse than France, in tenth position, does.
According to World Watch, urbanisation and income levels also tend to determine the type of waste generated. The share of inorganic materials in the waste stream, including plastics, paper, and aluminium, tends to increase as people grow wealthier and move to cities.
By contrast, the report said that waste flows in rural areas are characterised by a high share of organic matter, ranging from 40% to 85%. Similarly, organic waste accounts for more than 60% of MSW in low-income countries, but only a quarter of the waste stream in high-income countries.
The institute said that roughly a quarter of the world's municipal solid waste is diverted to recycling, composting, or digestion. Furthermore, recycling rates vary widely by country. In the U.S. the recycled share of MSW grew from less than 10% in 1980 to 34% by 2010, and similar increases have been seen in other nations, especially industrial ones.
The report found that the growing interest in MSW recovery is being primarily driven by the maturing of both regulations of markets for post-consumer materials. The instituted highlighted World Bank figures which put the value of the global market for scrap metal and paper at at least $30 billion per year. Additional statistics from the UN Environment Programme (UNEP) estimate the market for waste management, from collection through recycling, to be some $400 billion worldwide.
However, according to the report the UNEP also estimates that to 'green' the waste sector would require, among other things, a 350% increase in the recycling of MSW at the global level, including nearly complete recovery of all organic material through composting or conversion to energy.
The researchers said that the gold standard for MSW will be to integrate it into a materials management approach known as a 'circular economy' (read article on page 35), which involves a series of policies to reduce the use of some materials and to reclaim or recycle most of the rest.
According to the report Japan has made the circular economy a national priority since the early 1990s through passage of a steady progression of waste reduction laws, and the country has achieved notable successes. Resource productivity (tonnes of material used per yen of gross domestic product) is on track to more than double by 2015 from 1990 levels.
Furthermore, the recycling rate is projected to roughly double over the same period and total material sent to landfill will likely decrease to about a fifth of the 1990 level by 2015.