The dual pressures of climate change and plastic pollution are frequently conflated in the media, in peer-reviewed research and other environmental reporting.
The dual pressures of climate change and plastic pollution are frequently conflated in the media, in peer-reviewed research and other environmental reporting.
This is understandable. Plastics are largely derived from fossil fuels and the burning of fossil fuels is the major driver of human-caused climate change.
The window for cutting emissions to keep warming at internationally agreed levels is closing rapidly and it seems logical to conclude that any « extra » fossil carbon from plastic contamination will be a problem for the climate.
Our research examines this question using an Earth system model. We found carbon leaching out of existing plastic pollution has a negligible impact. The bigger concern is the production of new plastics, which already accounts for 4.5% of total global emissions and is expected to rise.
In nature, plants make organic carbon (carbon-hydrogen compounds) from inorganic carbon (carbon compounds not bonded with hydrogen) through photosynthesis. Most plastics are made from fossil fuels, which are organic carbon compounds. This organic carbon leaches into the environment from plastics as they degrade.
Concerns have been raised that this could disrupt global carbon cycling by acting as an alternative carbon source for bacteria, which consume organic carbon.
A key assumption in these concerns is that organic carbon fluxes and reservoirs are a major influence on global carbon cycling (and atmospheric carbon dioxide) over human timescales.
It is true that dissolved organic carbon is a major carbon reservoir. In the ocean, it is about the same amount as the carbon dioxide (CO₂) held in the pre-industrial atmosphere.
