What are greenhouse gases - and how do they cause global warming?

Just like a greenhouse, greenhouse gases seal heat inside the earth’s atmosphere, warming up the climate and contributing to global warming. The effects of global warming are being observed at an alarming rate: melting ice caps, natural disasters, rising sea levels, and droughts, to name a few. 

Human behavior has significantly contributed to global warming since the 1800s, when the use of fossil fuels became common. Since then, human activities have hurried climate change as we use more fossil fuels and energy sources to produce goods and electricity and toss out more trash that emits greenhouse gases. 

Carbon dioxide, nitrous oxide, methane, and fluorinated gases are the four most common greenhouse gases.

Carbon dioxide (CO2)
Carbon dioxide is created by the burning of fossil fuels (natural gas, oil, and coal), solid waste, trees, and other materials, or as a product of chemical reactions. 

Nitrous oxide (N2O)
Nitrous oxide is created through agricultural activity and land use, burning of fossil fuels, and treatment of wastewater.

Methane (CH4)
Methane emissions are produced by livestock and farming, waste decay, and the production and transport of fossil fuels.

Fluorinated gases
These potent gases are a group of potent greenhouse gases usually emitted in smaller quantities than carbon dioxide, methane, or nitrous oxide. Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are fluorinated gases that trap significantly more heat than CO2. 

How It’s Made: Gas Emissions from Plastic Production

Plastic creates gas emissions from the very beginning of production. Gas emissions from plastic production can be broken down into two steps: extraction & transport and refining & manufacturing. 

Extraction and Transport

Extraction is the first step in plastic production, when fossil fuel is pulled from the earth. Fossil fuels are extracted via mining and drilling. Drilling produces methane gas, and any combustion during extraction also emits greenhouse gases. Transport poses a new set of problems, like the energy consumption required to drill or mine and transport fossil fuels from far away sites to where it is eventually used. 

According to The Center for International Environmental Law, in 2015, in the U.S. alone, “Emissions from fossil fuel (largely fracked gas) extraction and transport attributed to plastic production were at least 9.5–10.5 million metric tons of CO2 equivalents (CO2e) per year. Outside the U.S., where oil is the primary feedstock for plastic production, approximately 108 million metric tons of CO2 per year are attributable to plastic production, mainly from extraction and refining.”

Refining and Manufacturing

The plastic industry is responsible for more greenhouse gas emissions during refining and manufacturing than almost any other industry. By 2050, it will be responsible for 20% of the world’s oil consumption. Plastic refining creates substantial emissions during the chemical refining process when raw material is turned into plastic. A 2015 survey revealed that a sample of two dozen ethylene facilities in the US produced over 17 million metric tons of CO2.

How It’s Disposed Of: Gas Emissions from Plastic Decomposition

Plastic poses a massive problem for the environment long after we toss it in the trash.  Unfortunately, less than 10% of plastic is recycled. In contrast, the remaining plastic waste is burned, winds up in landfills, or pollutes the planet. Let’s look at how plastic waste creates gas emissions.

Landfills or land pollution
Plastic waste takes centuries to decompose in a landfill or as land pollution. Plastic emits harmful methane and ethylene gases during the degradation process, which contribute to global warming. 

Aquatic pollution
Plastic pollution in the ocean is so overwhelming that a recent study estimated that plastic waste in the sea will reach 600 metric tons by 2040, and there may be more plastic than fish in the sea by 2050. Plastic in the ocean breaks down into microplastic, producing small granules of plastic debris. Microplastics can impair an organism's ability to sequester carbon dioxide, leading to global warming.

Plastic combustion
The combustion, or burning of plastic, is incredibly harmful to the environment. Burning of plastic is common in third-world countries and releases substantial air pollution, which hurts the planet and can cause serious health issues for those breathing in polluted air. In addition, black carbon emitted from burning plastic is 5000x more potent than carbon dioxide, with the potential to cause global warming at an alarming rate. 

How to Reduce Emissions from Plastic Waste and Prevent Global Warming

The only way to truly reduce emissions from plastic is simple: use less of it. Since the production, manufacturing, and disposal of plastic is deeply problematic, the best way to prevent global warming is to reduce our consumption of plastic. Here are a few easy ways you can decrease your plastic consumption.

-Switch to reusable whenever possible. For example, opt for refillable glass or metal water bottles instead of plastic bottled water, use silverware instead of plastic cutlery, and bring a reusable bag to the grocery store to tote home your goods instead of using plastic bags.

-Choose home compostable options. Some goods just can’t be reused: like trash bags and plastic bags used for food preparation. For these essentials, switch to a compostable option that is plant-based and nontoxic. For example, HoldOn bags are home compostable and use plant-based materials that break down cleanly without emitting harmful greenhouse gases. 

-Buy fewer pre-packaged items. Many products are sold with unnecessary plastic packaging. When shopping, look for unpackaged items and use your container - or don’t! - to bring them home. For example, rather than buying a package of bagged nuts at the store, look for canisters that allow you to fill your container. Bring a jar and fill away, then bring it home and enjoy it guilt-free!