Plastics are sometimes seen as environmentally friendlier than other materials - not least because of their light weight. But the plastics boom is pumping huge amounts of greenhouse gases into the atmosphere.
Making, using and disposing of plastic have serious effects on marine ecosystems, coastal environments and human health. While their impact on the climate is less well-known, it is just as significant.
In the 2015 Paris Climate Agreement, nations committed to limit global warming to well below 2 degrees Celsius - and to pursue efforts to keep the temperature rise below 1.5 degrees. In 2018, the Intergovernmental Panel on Climate Change concluded that to keep warming below the 1.5 degree limit, we must cut global greenhouse gas emissions by 45 percent by 2030, and we must reach zero net emissions no later than 2050.
In climate policy, attention is largely focused on the transition to renewable energy and cleaner transport. But industry is also important: it accounted for 30 percent of global greenhouse-gas emissions in 2010. The production of plastics is one of the largest and fastest-growing contributors to these emissions. Plastics, along with many fertilizers, pesticides and synthetic fibers, are petrochemicals, derived from mineral oil and natural gas. More than 99 percent of plastics come from such fossil-fuel feedstocks. Petrochemicals are
the fastest-growing form of oil consumption globally; the International Energy Agency forecasts that they will account for half of the extra demand for oil by 2050. In the United States and elsewhere, plastics and other petrochemicals form a large and rapidly growing destination for fracked gas.
As plastic production grows, it will lock in new fossil-fuel infrastructure and increase emissions that arise from the exploration, extraction, transport and refining of oil, gas, and coal. Global production of plastics has increased from 2 mil- lion tonnes in 1950 to 400 million tonnes in 2015. The production and use of plastics have nearly doubled in the last 20 years; they are expected to double again over the next 20, and quadruple by the early 2050s.
Carbon dioxide, methane and an array of other green- house gases are released at each stage of the plastics life cycle - from the extraction and refining of fossil fuels, to the energy-intensive processes that produce plastic resins, to the disposal, incineration, and potential environmental re- lease of waste plastics. This has big implications for efforts to meet global climate goals. To avoid overshooting the 1.5 degree target, total emissions must stay below the remaining (and quickly declining) budget of 420–570 billion tonnes of carbon dioxide.
The non-profit Center for International Environmental Law estimates that at current and projected rates of growth, the production of plastics alone could generate 53.5 billion tonnes of carbon dioxide emissions by 2050. Adding the incineration of waste plastics pushes this total up to nearly 56 billion tonnes. In other words, plastics alone could consume between 10 and 13 percent of the earth’s remaining carbon budget for staying below 1.5 degrees. Even assuming plastic production grows much more slowly after 2050, and incineration does not grow at all, emissions from plastic production and incineration could total nearly 260 billion tonnes of CO2 equivalent by the end of the century, potentially consuming over half the available carbon budget.
But these figures may still underestimate the total cli- mate impact of plastics. We know little about some aspects of the extraction, transport, and refining of fossil feedstocks for plastics. In North America, for example, official estimates of emissions from natural gas production routinely exclude the effects of forest clearance and other land disturbance needed for new drillpads and pipelines. Gas pipelines and facilities can leak substantial quantities of methane, a potent greenhouse gas - but government and industry estimates of the number of these facilities differ by orders of magnitude.
Emissions from plastics do not end when they are thrown away. Waste-to-energy projects that incinerate plastics are increasingly being proposed as a solution to plastic pollution. Because incineration emits a lot of greenhouse gases, the widespread deployment of waste-to-energy could lead to a big rise in emissions. The research group Material Economics projects that in Europe, incineration for waste-to-energy could make plastics a major source of emissions. And waste plastic continues to release greenhouse gases as it degrades in the environment. The true scale of these emissions is unknown.
The effect on emissions may also be indirect. Growing levels of microplastic debris in the oceans may interfere with the biological processes through which plankton capture carbon dioxide at the sea surface and sequester carbon in the deep oceans. The biological carbon pump is part of the oceanic carbon sink, contributing to the earth’s climate balance. The mechanisms and extent to which microplastics may be interfering with that balance are of great importance, but remain poorly understood. More research on these mechanisms and interactions is required.
This is a chapter from the Plastic Atlas 2019.