a new report says Wal-Mart is the biggest retail polluter in the U.S. Scott Olson/Getty Images

A new report is taking mega-retailer Walmart to task over its alleged high level of carbon-dioxide emissions.

Walmart is one of the biggest and fastest-growing polluters in the nation, despite the company’s 2005 pledge to become an environmental leader, according to a report from the Institute for Local Self-Reliance (ILSR).

The retail giant emits 45 million metric tons of CO2e (carbon dioxide equivalent), slightly more than Target, at 42 million metric tons, and significantly more than Costco, at 16 million metric tons, according to the report.



“The scale of Walmart’s energy efficiency and renewable power measures is not up to the scale of their business or their growth,” Stacy Mitchell, the author of the report, told Al Jazeera. “They been placing solar powers on the rooftops and getting some wind power and so on, but Walmart only derives 4 percent of its energy from renewable energy sources.”

Mitchell, a senior researcher at ILSR, says Walmart is the largest offender of CO2 emissions by a wide margin, and a large part of its high emission levels can be attributed to its business model.

“This is a business model that is built on these far-flung distributors and goods that are trucked all over the country," Mitchell said. "There are fundamental aspects of Walmart’s business model that are at odds with sustainability.”

Walmart spokesperson Christopher Schraeder told Al Jazeera that the company is “working hard every day to find solutions to the most pressing sustainability issues,” and that it has “ambitious sustainability goals to improve our operations, increase fleet efficiency, source locally and sell more sustainable products.”

Schraeder said the Environmental Protection Agency lists Walmart as the nation’s largest on-site green power generator, adding that the Solar Energy Industries Association says Walmart has the most installed solar capacity in the U.S. Walmart, Schraeder added, reports it’s CO2 emission levels to the Carbon Disclosure Project.

The ILSR report, however, challenges that, saying Walmart only reports emission levels from domestic shipping and electricity uses, but does not report emissions from international shipping, land development and construction, increases in consumer driving to their stores and manufacturing emissions from its store-brand products.

Mitchell acknowledged that significant change in emissions will have to come through legislation, not just from companies becoming more ‘green.’

But with Congress more divided than ever, that’s not likely to happen soon, especially when companies use their financial resources and lobby members of Congress to block environmental protection measures.

Through the Walmart Stores Inc. PAC for Responsible Government, Walmart has given more than $22 million to politicians who are opposed to legislation that would regulate emissions and promote climate change.

In the 2008 elections, 80 percent of Walmart’s senate campaign contributions went to people who blocked the “cap-and-trade” bill, which would have reduced carbon dioxide and other greenhouse gas emmissions across the U.S. economy. In the 2012 elections, 70 percent of donations went to people who supported the Keystone XL pipeline.

“Walmart clearly has the financial resources to do things like move to renewable power more than it has,” Mitchell said. “It is the big-box store model that isn’t sustainable.”