Waste, Pollution and Recycling

About this topic

Humans produce billions of tonnes of waste each year. Pollution affects air (smog, particulates), water (sewage, plastics, chemicals) and land (landfill, toxic waste). Plastics persist for centuries and fragment into microplastics that enter food chains.

The waste hierarchy: reduce, reuse, recycle, recover energy, dispose last. Composting turns organic waste into soil improver. Regulations, extended producer responsibility and a circular economy aim to cut waste. Personal choices like avoiding single-use items help.

An average person in a high-income country generates about 1.5 to 2 kg of municipal waste a day. Plastic is a vivid example: a bottle may take about 450 years to break down, and about 8 million tonnes of plastic enters the ocean each year, harming seabirds, turtles and fish. Microplastics smaller than 5 mm have now been found from Everest to the deep sea and in human blood. Landfills produce methane as organic waste rots, so diverting food waste to composting or biogas plants reduces emissions.

Recycling saves energy: making steel from scrap uses about 60 percent less energy, and recycled glass can be reused endlessly. But recycling only works when materials are sorted and clean, and some plastics are hard to recycle, so reduction and reuse are higher priorities. Air pollution such as PM2.5 particles causes millions of premature deaths a year, and water pollution spreads disease. Solutions include clean energy, wastewater treatment, deposit return schemes and designing products to last. A common misconception is that putting something in the recycling bin guarantees it is recycled; contamination can send loads to landfill. Another is that individual actions do not matter; combined with policy, they shift markets.