Plastic's Contribution to Climate Change
The problem with plastic isn’t only about the visible pollution that’s evident everywhere we look today.
Plastics also make a significant – and growing - contribution to man-made climate change.
How do plastics contribute to climate change?
All plastic is made from carbon, but while biopolymers or bioplastics use carbon derived from natural materials, man-made plastic uses carbon derived from oil.
Most plastics are produced by a process of ‘cracking’ and refining crude oil, natural gas and other petroleum products, otherwise known as fossil feedstock. The feedstock is broken down into various constituent hydrocarbons such as ethylene, propylene and styrene. These are further processed to make plastic pellets known as ‘nurdles’, ready to be extruded or molded into a wide range of plastic products.
The processes used to extract the oil or gas from the ground use huge quantities of fossil fuel energy, releasing greenhouse gases and other pollutants into the air. More energy is used to transport the raw materials to manufacturing facilities, and subsequently to produce, transport and dispose of the end products.
The entire process is fuel intensive and carbon heavy; around 4% of current global oil consumption is turned into plastic, and another 4% is used to power plastic manufacturing processes[i], emitting many billions of tons of carbon dioxide into the atmosphere every year. The process of making each kilogram of virgin plastic releases 2-3kg of carbon dioxide.
Trucost, a research arm of the financial-information provider Standard & Poor’s, has put the overall social and environmental cost of plastic pollution at $139bn a year, half of which arises from the climate effects of greenhouse-gas emissions linked to producing and transporting plastic.
What types of plastics are causing the biggest problem?
Although there are many types of plastic, the five most common make up around 85% of the world’s plastic consumption by weight. These five plastics are:
- Polyethylene (32% of global demand)
- Polypropylene (23%);
- Polyvinyl chloride or PVC (16%)
- Polystyrene (7%)
- Polyethylene terephthalate or PET (7%)
Propylene is the primary feedstock for polypropylene; ethylene is the primary feedstock for the other four[ii] - but all are derived from fossil fuels.
We shouldn’t forget that it’s not just production of plastics that accelerate climate change; a large proportion of the waste plastic that is thrown away is incinerated (around 36% in Europe[iii]).
Where this takes place in an energy-from-waste plant, it can be argued that it is a form of renewable energy and more sustainable than some other energy sources. This type of combustion does, however, still emit carbon dioxide (and other airborne pollutants) and contributes towards global warming.
How much of a problem is this for the climate?
Plastics can be made from other raw materials including biomass in the form of starch, cellulose, sugars, organic waste and vegetable oils. In fact, the very first plastics were made well before oil was used as a feedstock.
However, the convenience of hydrocarbon cracking and availability of oil means that today, more than 99% of plastics are produced from chemicals sourced from fossil fuels[iv].
And the problem is likely to get worse. The availability of cheap shale gas in the US is driving new investments in plastics manufacturing facilities, with 264 new or expanded factories planned in the US alone[v].
In just five years’ time, these developments could increase global plastics production capacity by one third, locking-in manufacturers to produce ever greater volumes of plastics for years to come.
The World Economic Forum estimates that by 2050, plastics will be responsible for nearly 15% of global carbon emissions, making it a bigger climate polluter than aviation, which is currently accountable for 12% of global carbon emissions.
Should be concerned for the future?
At a time when the world’s nations are attempting to cut harmful greenhouse gas emissions, the continued increase in the use of fossil fuels in the plastics industry is unsustainable.
To limit global warming to below 2 degrees Celsius above pre-industrial levels, in accordance with the 2015 Paris Agreement, we need to reduce the amount of fossil fuels used to produce single-use, disposable plastic, in particular.
If we fail to achieve the Paris goals, we face the consequences of catastrophic climate change; is our addiction to plastic really worth the risk?