So plastics. Plastics come in all shapes, forms and colors. They are everywhere. They are in our makeup, it packages our food and insulates our homes. They are in airplanes and our favorite electronic devices. They are truly a remarkable material.

But so are its troubles. And we produce and consume plastics in staggering quantities. Since it\'s been mass-produced, the world has created over 10 billion metric tons of it. Half of them just in the past 20 years.

I have been investigating plastic pollution [for] about a decade, and I try to align my personal choices as a consumer with the aspirations of my research. And you may think, “Oh, that’s easy, you know how to do it.” But actually it’s not. Sometimes it\'s impossible to avoid single-use plastics. The system is built that way.

The dominant narrative about plastics tell us that this is a consumer’s and a waste management problem. Who of us here have not heard about the tales of gigantic plastic islands floating in the middle of the ocean? Which, by the way, it\'s not true. And that low-income countries are to blame for most of the plastic waste entering our oceans. But this narrative is a misleading oversimplification of a much bigger and complex story.

Plastics and their chemical additives are really a climate problem.

Now, we need to think of plastics from a systemic perspective. So let me take you through the journey of plastics. Plastics contribute to climate change from before the moment they are produced to long beyond the moment they are disposed or landfill or drift into the ocean. And it will remain in the environment for centuries, degrading ecological processes.

For 99 percent of all plastics the starting point is fossil fuel hydrocarbons. Oil, gas and coal are extracted and refined to produce plastic and other synthetic chemicals. And those processes generate greenhouse gases such as CO2 and methane. Studies indicate that if nothing is done, the production of single-use plastic alone will contribute to more than 10 percent of all greenhouse gas emissions by 2050.

And the thing is that our use of plastic last often just a few minutes or a few hours, then we throw them away, and that generates further emissions. And we know that our recycling system doesn\'t work. It\'s broken everywhere. And recycling plastics is hard and not cost-competitive. Most of the waste that has not been landfilled or incinerated domestically is shipped across the planet, and it reaches low-income countries where they are expected to be recycled. But this is one of those hypocrisies of globalization where rich countries outsource their problems to low-income countries. And we know that these countries do not have the capacity nor the technology to deal with them in a soundly manner. And so huge amounts of plastics are illegally incinerated, informally dumped or get lost at sea. And as a result, millions of tons of plastic every year get into our environment. But even plastics that are soundly managed emit greenhouse gases.

Once plastics enter the environment, landfill, are dispersed in soil or water, they start a process of breaking down into micro and nanoparticles. I will just call them microplastic for the sake of the conversation today. And this process of breaking down emits powerful gases such as methane, ethylene and CO2. And that\'s true for both traditional and biodegradable plastics. On the surface of microplastics, new microbial communities can grow. We call them the plastisphere. And their biological activity also releases additional CO2 and nitrous oxide into the environment, creating the possibility of further magnifying the climate problem. It means that microplastic can also impair the growth and the photosynthesis capacity of phytoplankton, which are the microorganisms producing much of the oxygen we breathe. But also microplastics can have toxic effects on zooplankton, and the health of these organisms [is] essential for the functioning of all aquatic food webs.

And unfortunately, the problems run even deeper. Microplastics bind with the so-called marine snow, which are made out of the clumps of bacteria, plankton and other organic material that sinks down into the ocean depth, acting like a biological carbon pump. But microplastics risk affecting this marine snow and potentially decreasing the capacity of the ocean to absorb and sequester carbon from the atmosphere. And microplastics can be decreasing the reflective properties of snow and ice, potentially accelerating the melting of glaciers and polar ice.

So we have early enough indications that plastic pollution is starting to change the processes that allow the Earth\'s climate system to work. And this pollution is not a localized phenomenon. Microplastics are everywhere, from the mountaintops of Everest to the deepest sediment in the Mariana Trench. They are in the air we breathe, the water we drink and the food we eat. They are now found in our bloodstream and our lungs. And personally, the most terrifying, in the placenta of our unborn children.

Now, of course, plastic is a great material, it\'s versatile and durable, and in many ways it has allowed modern civilization to develop in the way it has. But it also comes with a lot of problems and the outlook is worrying. Today, the total mass of plastic is twice the total mass of all living organisms on the planet. But still, fossil fuel companies see hydrocarbon as their primary growth sector projecting a 30 percent increase of virgin plastic for single-use plastic just in the next five years. We already see an accelerating pace in producing and releasing new chemicals because there are many, many kinds of plastic. Each one the result of a different chemical formula. And we know that this is incompatible with staying within the safe operating space for humanity. And given how plastics impact the climate and the world\'s social ecological system, this would spell a catastrophe.

By the way, I\'m not saying that we are completely doomed yet. There are solutions. And it’s that worldwide, entrepreneurs and companies are creating new designs and material that can substitute traditional single-use plastic. And social movements are consolidating and educating people to reduce their plastic footprint and pressuring local and world policy makers to enact strong policies. And scientists are collaborating more than ever, communicating the urgency to limit not only the volume, but the chemical diversity of plastics. And earlier this year, representatives from over 170 nations at the UN Environment Assembly adopted an initiative to end plastic pollution, committing all these countries to participate in creating, by 2024, a legally binding agreement that addresses the full life cycle of plastics, from production to design to disposal.

We need to stop thinking of plastic just as a waste problem, one that can be solved by changing consumers\'s habits alone and stopping using plastic bags. We need to think of plastics as a climate problem, as a product that creates damage along all its journey, from the drilling up of hydrocarbons to the spread of microplastics. And that can only be addressed in a systemic way.

Thank you.

出自卫报