How Your Trash Is Contributing to Climate Change

Correction appended, Sept. 22

Americans dumped twice as much trash into landfills in 2012 as previously estimated, according to new research, suggesting trash may be contributing to climate change more than scientists believed.

The new figures, published in the journal Nature Climate Change, show Americans disposed a total of 262 million tons of waste in 2012. The study’s lead author, Yale University researcher Jon T. Powell, notes that previous research has used indirect information, like trade data, to measure trash levels in landfills, potentially leading to lower estimates. His study aims to provide a more accurate estimate by using data taken from individual landfills.

The higher numbers are especially significant because trash in landfills releases methane gas, a greenhouse gas that contributes to climate change. The Environmental Protection Agency (EPA) estimates that landfills are the third-leading cause of methane emissions in the U.S. Nearly a fifth of of methane emissions come from landfills. Landfills utilize methane gas collection technology, but researchers say that methods should be improved at open landfill sites.

“We’ve got a lot of waste going into landfills, more than what’s been reported before,” said Powell. “What that means for the long term is that we’re going to have greater emissions.”

Read More: EPA Proposes New Rules to Cut Climate Change-Causing Methane Emissions

Methane is the second most prevalent gas emitted by human activity following carbon dioxide. And, while Americans emit significantly less methane than carbon dioxide, methane emissions are 25 times more damaging to the environment, pound for pound, than carbon dioxide over a 100-year period.

The EPA recently announced new rules to reduce methane emissions, but the policies target the oil and gas industry without taking on key sources of methane emissions like landfills and agriculture. (In a different announcement, the agency proposed requiring more landfills to capture methane gas emissions). The need to address pollution from landfills may be growing as urbanization pushes people into cities and increases waste. Today, 54% of people around the globe live in cities, and those cities could see their populations rise by 2.5 billion by 2050, according to a United Nations estimate.

“As that urbanization occurs, you have more materiality, more consumption, and that begets residuals of waste materials,” said Powell.

Correction: The original version of this story misstated the name of the study’s lead author. He is Jon T. Powell.