Nations Underestimate Wastewater Emissions, Fixable Lapse

Updating measurement methods could help countries accurately report greenhouse gas emissions from wastewater facilities.

Published on Feb. 27, 2026

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Research from Princeton University has found that nations worldwide are underestimating greenhouse gas emissions from wastewater facilities. The study shows that countries are relying on outdated inventory methods and failing to include items like latrines and untreated sewage in their national reports, leading to underestimates ranging from 19 to 27 percent. The researchers say that updating to more accurate 2019 measurement standards could help countries better account for these emissions.

Why it matters

Accurate emissions data from the wastewater sector is crucial for developing effective policies and technologies to reduce greenhouse gas output. Wastewater systems are among the largest emitters of potent gases like methane and nitrous oxide, but have not received as much attention as other high-emission sectors like transportation and power generation.

The details

The study examined 38 countries on five continents, finding that 26 developed countries and 12 emerging economies were all underestimating wastewater emissions. The researchers determined that about 94-150 million metric tons of carbon dioxide equivalent is missing from annual global emissions data due to gaps in accounting for certain wastewater systems. They say that wastewater infrastructure often lasts for decades, so improving measurement and reporting now can have long-lasting impacts.

  • The research article was published on February 11, 2026 in the journal Nature Climate Change.
  • The 2006 IPCC guidelines that many countries currently use to estimate wastewater emissions have since been updated with more accurate methods in 2019.

The players

Z. Jason Ren

A professor of civil and environmental engineering and the Andlinger Center for Energy and the Environment at Princeton University, who led the research.

Princeton University

The institution where the research was conducted.

Intergovernmental Panel on Climate Change (IPCC)

The United Nations body for assessing the science related to climate change, whose 2006 and 2019 guidelines on measuring wastewater emissions are central to the study.

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What they’re saying

“If you don't know exactly how much emissions you have, then it's really difficult to make effective policies or technologies or methods to reduce the emissions.”

— Z. Jason Ren, Professor (Mirage News)

“As a researcher, I want to understand the process better to put in better technologies and avoid, I don't want to say disastrous, but very unfortunate scenarios.”

— Z. Jason Ren, Professor (Mirage News)

What’s next

The researchers have urged the IPCC and policymakers to update national inventory guidelines to incorporate the more accurate 2019 wastewater emissions measurement methods.

The takeaway

Improving how countries measure and report greenhouse gas emissions from wastewater systems is a crucial but often overlooked step in developing effective policies and technologies to reduce the sector's substantial climate impact.