Plastic is a much less efficient carbon sink than the original crude oil if it had been left in the ground or any natural method for storing carbon such as peat bogs. It is still technically a carbon sink but is starting to be broken down naturally so is not a renewable or sustainable one.

Is carbon stored in plastic?

Plastics, no matter the source, are mainly made of carbon – about 80 percent by weight. ... Even if bio-polymers end up in a landfill, they will still serve this carbon storage role. CO₂ is only about 28 percent carbon by weight, so polymers comprise an enormous reservoir in which to store this greenhouse gas.

Does plastic contribute to carbon footprint?

By 2050, plastic production and incineration could emit 2.8 gigatons of CO2 per year, releasing as much emissions as 615 five-hundred-megawatt coal plants. Critically, these annual emissions will accumulate in the atmosphere over time.