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New and concerning findings from environmental scientists about the impact of microplastics on crops and marine algae add to a growing body of evidence about the disruption caused to living systems by plastic pollution. The results, from a team led by Prof Huan Zhong at Nanjing University, China, are not definitive and require corroboration. But analysis showing that plastics could limit photosynthesis (the conversion of sunlight into chemical energy) must be taken seriously. If the researchers are correct, and staple crops are being reduced by about 12%, there are huge implications for global agriculture and food supplies. This could inject new urgency into efforts to tackle plastic pollution.
There is no single route by which microplastic particles inhibit plants from growing. The overall effect is attributed to a combination of blocked sunlight and nutrients, and damage to soil and cells. This can lead to reduced levels of chlorophyll – the pigment enabling photosynthesis. When the researchers modelled the crop losses caused by an effect of this size, they found Asia was hardest hit, potentially contributing to food insecurity and worsening hunger.
The extent of the contamination of the Earth by microplastics has been widely documented. The tiny particles that are formed when plastics break down in the environment have been found in human semen, breast milk, brains, livers and bone marrow, and in remote areas including the Arctic seas. The more than 500m tonnes of plastics that are produced annually, most of which are dumped rather than recycled, leave their mark everywhere. Plastic is already understood to pose serious hazards to animals including sea creatures, which can be poisoned and injured by it. It also ruins landscapes, with serious implications for the people who live in them and anyone trying to make a living from tourism.
But there is still much to learn about the less obvious forms of damage caused by plastic pollution to humans and ecoystems. Links to strokes, heart attacks and preterm births are all cause for concern. One new study, presented at a conference in January, found that microplastic pollution was 50% higher in the placentas of babies born prematurely.
Talks in South Korea aimed at agreeing a UN treaty on plastic pollution ended in failure in December. Almost all single-use plastics are made from fossil fuels, and fossil-fuel states and businesses oppose any limits on production. Record numbers of industry representatives at the summit meant that lobbyists outnumbered those attending for European governments. Perhaps as a result, though more than 100 countries supported a draft text including legally binding reductions and the phase-out of some substances, no final deal was reached.
When talks reconvene in Switzerland later this year, these states must turn up with a plan. Under Donald Trump, the US is likely to ally itself with Russia and Saudi Arabia, meaning that making a deal will be even harder this time round. But the enormous volume of plastic waste, and the growing evidence of the range of harms it causes, mean action must be taken. Plastic will continue to have its uses, but the proliferation of single-use items, including packaging, is out of control. Just 9% of plastic gets recycled – and the recycling process itself can increase toxicity. Fossil-fuel interests must be confronted over plastic pollution just as they are challenged over global heating caused by coal, oil and gas.
