Context: Newly published research calculates that across their lifecycle, plastics account for 3.8 per cent of global greenhouse gas emissions. That’s almost double the emissions of the aviation sector. If it were a country, the “Plastic Kingdom” would be the fifth-highest emitter in the world.

Why worry about this?

Demand is set to rise, too. At 380m tonnes a year, we produce 190 timesmore plastic than we did in 1950. If the demand for plastic continues to grow at its current rate of four per cent a year, emissions from plastic production will reach 15 per cent of global emissions by 2050.

Plastic across the lifecycle:

More than 99 per cent of plastics are manufactured from petrochemicals, most commonly from petroleum and natural gas. These raw materials are refined to form ethylene, propylene, butene, and other basic plastic building blocks, before being transported to manufacturers.

The production and transport of these resins requires an awful lot of energy — and therefore fuel. Greenhouse gas emissions also occur during the refining process itself — the “cracking” of larger hydrocarbons from petrochemicals into smaller ones suitable for making plastic releases carbon dioxide and methane.

Contribution to greenhouse emissions:

• According to the study, about 61% of total plastic greenhouse gas emissions comes from the resin production and transport stage. A further 30 per cent is emitted at the product manufacturing stage. The vast majority of these emissions come from the energy required to power the plants that turn raw plastic materials into the bottles, bin bags and bicycle helmets we use today. The remainder occurs as a result of chemical and manufacturing processes – for example, the production of plastic foams uses HFCs, particularly potent greenhouse gases.
• The remaining carbon footprint occurs when plastics are thrown away. Incineration releases all of the stored carbon in the plastic into the atmosphere, as well as air pollutants such as dioxins, furans, mercury and polychlorinated biphenyls, which are toxic and damaging to human health.
• As plastics take centuries to degrade, disposal in landfill makes only a small contribution to emissions in theory. However, as much as 40 per cent of landfill waste is burnt in open skies, dramatically speeding up the release of otherwise locked-up carbon.

Need of the hour:

• If we are to combat climate breakdown, reductions in plastic emissions are clearly needed. In showing that transitioning to a zero carbon energy system has the potential to reduce emissions from plastic by 51 per cent, the study provides yet another reason to rapidly phase out fossil fuels.
• However, beyond urgently required global decarbonisation, we need to reduce our seemingly insatiable demand for carbon-based plastic. Increasing recycling rates is one simple way of doing this.
• A more fundamental solution is to switch to making plastics from biodegradable sources such as wood, corn starch, and sugar cane. The materials themselves are carbon neutral, although renewable power is essential to eliminate the climate impact of energy costs during production, transport and waste processing.
• Governments, corporations, and individuals must make research into alternatives a priority, and support alternatives to needless plastic waste.

Conclusion:

Plastics need not be completely demonised as environmental scourges. Affordable, durable, and versatile, they bring a raft of societal benefits, and will undoubtedly serve an important role where replacements are unable to be found. But decades of unbridled use and a throw-away culture are having grave consequences that go far beyond the visible pollution of our land and water. It is essential that we drastically reduce our use of avoidable plastics, and eliminate the carbon footprint of the ones we need to use. Our relationship with plastic may be toxic, but it doesn’t need to be forever.