What Does Plastic Have to do With Climate Change?

Wednesday, September 20, 2023

Over the past decade, the issue of plastic waste has received growing attention, as powerful images of plastic in the natural environment have reached global audiences. Yet, some critics have called the public focus on plastic a “dangerous distraction” that “overshadows greater threats” and hinders action on “bigger issues” that “really matter,” including climate change. The two issues, however, should not be pitted against one another, as they are inextricably linked. Not only do the greenhouse gas (GHG) emissions embodied in plastic directly contribute to climate change, but climate change will also exacerbate the negative impacts of plastic pollution.

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In 2019, plastic generated 1.8 Gt, or 1.8 billion metric tons, of GHG emissions; equivalent to 3.4% of the world’s total GHG emissions for that year. Plastic produces these emissions over the course of its lifecycle, which begins with its production. Plastic is derived from oil and natural gas, two of the main culprits behind climate change. After these fossil fuels are extracted from the Earth, they are processed in refinery plants, where they are distilled and “cracked” into various hydrocarbon compounds, including olefins, which are the building blocks of plastic. These olefins are then processed further at petrochemical plants and turned into “virgin” plastic, which can be melted and reshaped into plastic products (e.g., bottles, packaging, electronic equipment, etc.) at individual manufacturing facilities. The emissions from these stages of its lifecycle account for 90% of plastic’s total emissions. In other words, almost 3% of global GHG emissions can be attributed to the primary production of plastic.

Putting aside the emissions embodied in the transportation of plastics and its source components, another way in which plastic generates GHG emissions is through its end-of-life stage as waste. After plastic reaches this stage—which may take anywhere from a couple of minutes to a couple of decades—it is either recycled, landfilled, or incinerated. These waste management methods lead to 161 Mt, or 161 million metric tons, of GHG emissions every year.

Plastic that escapes the waste management system—for example, through litter and illegal dumping—is considered “unmanaged waste” and can amplify climate change and its impacts in various ways. For example, unmanaged plastic waste can eventually degrade into microplastics, bits smaller than five millimeters (mm) in size. As this degradation occurs, GHGs such as methane and ethylene are released. Furthermore, atmospheric processes transport microplastics to some of the most remote regions of the planet, such as the warming-sensitive Arctic. Here, researchers note that microplastics might decrease the albedo of snow and ice—the fraction of reflected light—which would increase surface temperature and accelerate melting. Microplastics and nanoplastics—plastic particles less than 0.001 mm in size—might even affect cloud formation processes, which could influence weather patterns.

Currently, petrochemical products—of which plastic is the largest—account for 14% of global oil production. Under a business-as-usual scenario, the International Energy Agency estimates that this figure could reach 50% by 2050. Accordingly, oil and gas companies are betting on plastics. The industry has plans to spend $400 billion on new petrochemical capacity. By 2050, annual plastic production could increase to almost 600 Mt, a 50% increase over current levels. Under this scenario, the production and consumption of plastics is expected to produce 56 Gt of cumulative GHG emissions by 2050. This would exhaust 10-13% of the remaining carbon budget needed to mitigate end-of-century warming to levels below 1.5°C, in accordance with the most ambitious goals of the Paris Climate Agreement.

Evidently, plastic does, and will continue to, contribute to climate change. Additionally, the resulting symptoms of climate change, such as more severe storms and heatwaves, could amplify the negative effects of plastic pollution on the environment and ecosystems.

The approximately 10 million tons of plastic waste that leak into the oceans annually—equivalent to 1 garbage-truck load every minute—kill millions of marine animals each year. This plastic also degrades into ingestible particles that make their way into the food system, leading to humans consuming about half of a pound of plastic each year, on average.

Climate change will likely exacerbate plastic pollution by amplifying its scope and impact on the aquatic environment. For example, research has shown that extreme weather events, such as coastal storms, could lead to increased input of microplastics into coastal waters and rivers. Accelerated melting of Arctic sea ice, which contains between 38 and 234 microplastic particles per cubic meter, could also release additional plastic into remote regions of the high north. In addition, social-science research indicates that warming could boost the demand for bottled water, which may lead to further plastic waste.

Climate change and plastic pollution also impact many of the same marine ecosystems, potentially compounding the effects of each individual stressor. For example, increasing ocean temperatures are leading to more coral bleaching events, which can cause mass coral mortality and local species extinction. These coral reefs might become less resilient to other stressors, such as plastic pollution, which can inhibit their growth and photosynthetic performance, increase disease likelihood, and inflict physical damage upon them.

Warmer waters are also rendering temperate ecosystems more vulnerable to invasive species from tropical areas. Marine plastic debris might escalate this problem, as plastics have been shown to transport invasive species—especially encrusting organisms like coralline algae, barnacles, and bivalve mollusks—across oceans to new ecosystems.

Finally, research indicates that both climate change and plastic pollution might lower the ocean’s primary production—the conversion of sunlight to biomass that supports the entire marine food web. Subsequently, primary consumers, like zooplankton, could be hurt both by the reduction of their food supply as well as the increased concentration of microplastics, which some regularly mistake for food. Both negative effects—the reduced overall biomass and increased ingestion of microplastics—could spiral up the food web and reach us humans.

As we begin to examine solutions, it is instructive to consider how the burden of plastics mirrors that of climate change; it is disproportionately borne by low-income and minority communities, as well as developing countries, despite these groups playing a smaller role in creating the problem itself.

To extract the oil and gas needed to produce fossil fuels and plastic, acres of wildlife are cleared, and nearby water is polluted, harming the local communities—often, indigenous communities—that may depend on those systems.

In addition, oil refineries, petrochemical plants, and incinerators are all disproportionately sited near low-income, communities of color. Research has shown that the air pollutants associated with these facilities can lower air quality for nearby communities, which can increase the risk of cancer and other negative health outcomes. Marginalized communities are also more likely to live near landfills. This puts them at a higher risk of health issues due to soil contamination and water pollution from landfilled plastic, which can leach toxic chemicals such as phthalates and bisphenol A (BPA) into the environment.

At the global level, developed countries use up to 20 times more plastic than developing countries, but bear proportionately less of the burden, as plastic waste is often shipped to developing countries or can leak into global waterways. This inequitable distribution of costs and benefits plays out in climate change as well, as developed countries are responsible for 79% of historical GHG emissions but developing countries will bear the heaviest burden.

Finally, there is an intergenerational justice component to both plastic pollution and climate change—future generations will bear the largest burden of present and past GHG emissions, just as they will have to deal with the spread of plastic pollution that they had less part in creating.

The U.S. National Academies of Sciences (NAS) has identified potential policy solutions for mitigating both climate change and plastic pollution. These policy frameworks, like the issues they seek to address, share some common threads. For example, the NAS notes that climate change solutions largely rely upon addressing the issue at its source through deep reductions in GHG emissions. These reductions, the report continues, are necessary to achieve the United States’ goals of net-zero emissions by 2050. Similarly, the NAS has found that reductions in plastic production—that is, addressing the issue at its source—is the first step to stemming plastic pollution. The NAS report suggests that the United States should consider reducing production of virgin plastic, creating plastic reduction targets as part of federal and state GHG emission goals, and issuing a moratorium on new petrochemical plants.

Secondly, the NAS report indicates that additional policies should encourage innovation to transform the design of products typically made from plastic. This could be done through limits on plastic content for certain products, as well as funding, standards, and regulations that promote innovation and collaboration across the industry. A third set of policy solutions put forward by the NAS aims to decrease waste generation through, for example, replacing single-use plastics with reusable alternatives. Such remedies might be analogous to the recommended transition away from fossil energy and toward renewables, which is achievable in part due to innovation in the energy sector, according to the NAS.

The NAS report also notes that policies that improve waste management should be implemented. Examples of such policies include investments in better infrastructure to improve source separation and recycling, as well as the creation of wastewater treatment standards to capture microplastics. Lastly, the NAS notes that policymakers should consider targeting unmanaged waste as well; for example, they could encourage land and water-based cleanups or increase enforcement to combat illegal dumping and disposal of trash. These solutions are comparable to proposals of carbon capture and storage as a strategy to address climate change. While removing existing waste—and atmospheric carbon—is important, these proposals are not likely to be effective solutions unless accompanied by changes that target the source.

Looking to the future, the production, waste, and negative impacts of plastic are only projected to increase under a business-as-usual scenario. As we consider holistic solutions to the issue, we can draw insights from parallel themes in the climate change sphere. The two issues share more than just similarities—from overproduction to inequity—they are also joined at the hip. As climate change and plastic pollution will amplify the consequences of one another, policymakers could seize the opportunity to design connected solutions that tackle both issues.