Climate Change and the Future of Plastics
The future of plastics is still great, but not without some radical changes in the way we make them.
The advice that Dustin Hoffman’s character got in the 1967 film The Graduate (“There’s a great future in plastics”) turns out to have been pretty good. Plastic sales have grown tenfold since then, and there is no sign that it is slowing down. This is easy to understand. Plastics are cheap, waterproof, and do not decay. Plastic packaging reduces food waste. Lightweight cars and carbon fiber wind machines are important tools in fighting climate change. It is hard to imagine modern medicine without plastics. But there is a huge hidden cost: a flood of plastic waste and a much-less-recognized impact on climate change. Solutions are treacherous. Short-term fixes may undermine long-term solutions.
Our Plastic Problem
Nothing about plastics is easy. There are hundreds of plastic products, multiple manufacturers, and a complicated brew of environmental impacts. Plastic waste on land and in the ocean is a major threat, and microplastic pollution seems to be making all of us part plastic. And plastics are also a major contributor to climate change. Plastics present an unusual problem since most of the oil, gas, and coal used in the production of plastics end up as part of the plastic. Plastic is, in effect, transformed fossil fuels. The scale is staggering. Petrochemical production—including plastics—is likely to become the largest consumer of fossil fuels.
Most of the carbon in plastic waste is likely to end up in the atmosphere as a greenhouse gas—the key question is how long this will take. The answer is clouded since lifetimes depend on the type of plastic and its history as waste. Although the most authoritative recent study found roughly a third of plastic waste had fairly short lifetimes (three – 87 years in the ocean), 20-30% had extremely long lifetimes (at least 2,500 years). Information on the rest is largely missing. Recycling and storage in modern landfills can delay or prevent the release of greenhouse carbon but only about a quarter of plastic waste ends up in these places.
Most current recycling technologies, however, may reduce ocean and land pollution but are far from managing long-term climate impacts. Biodegradable plastic, for example, may help in the short term but releases its carbon quickly. Waste can be ground up or otherwise converted into other plastic products, but these products are usually inferior to the original materials and will eventually end up discarded. Chemical processes can also be used but most capture only part of the carbon in the waste and must be integrated with existing refineries.
Innovations in Plastics
Plastics compatible with climate change will require some dramatically new ideas. The good news is that there are lots of them. The biggest challenge is usually not finding technologies that work but finding systems that can compete with plastics made from “virgin materials” (the industry term for plastics made from fossil fuels)—in which no price is paid for the environmental damage created.
Recycling fossil-based plastics with little or no greenhouse gas emissions could be possible if plastics are efficiently disassembled and reassembled. This can be much easier if they are designed so that they can be easily taken apart. And there’s interest in modifying bacteria and fungi so that they can digest plastic and convert it to useful materials, an improvement on conventional chemical recycling.
Technologies are available for capturing most but not all of the carbon dioxide released from conventional plastic production and storing it permanently underground. They are bulky and expensive but clearly work.
A more radical solution that cuts greenhouse emissions from both plastic production and the decay of plastic waste is to make plastics without using fossil fuels. One approach uses plant materials as a substitute. Plants take carbon dioxide out of the air and convert it into complex chemicals that could be used to make plastics. There are problems. Any plastic waste made from plants would eventually return this carbon dioxide to the air. Growing and harvesting plants lead to greenhouse gas emissions, and the supply of plant materials that can be produced without driving up food prices or creating environmental harm is limited.
There is a potential home run. A number of research groups are developing electric-powered devices that convert carbon dioxide and water to chemicals used to make plastics. There are even prototype devices that are powered entirely by sunlight—getting one step closer to an artificial plant, possibly one that is more efficient than the real ones. These technologies should be high on the list of climate change priorities (but are not).
Sadly, these technologies do not solve near-term environmental issues such as microplastics and ocean debris from green plastic production. Reducing use of hard-to-collect plastics like packaging will be essential. Plastics that reliably degrade everywhere must be part of the solution.
A possible wild card: we might be able to turn plastics with long life expectancies into an asset if we could find a way to collect and store them securely for thousands of years. This approach would actually remove carbon dioxide from the air if the plastic was made with renewable, plant-based resources. But serious questions remain unanswered, including “how long is long enough?”
A 2022 whisper to a graduate might well say that the future of plastics is still great, but not without some radical changes in the way we make it.
Dr. Henry Kelly is a Senior Fellow at the Boston University Institute for Global Sustainability. Previously, he served in senior positions in the White House Office of Science and Technology Policy and the Department of Energy during the Obama Administration.
The opinions expressed herein are those of the author and do not necessarily represent the views of the Boston University Institute for Global Sustainability.