There are no records of the Clinton campaign purchasing carbon offsets in their latest Federal Election Commission reports released earlier this month and, when asked, multiple campaign aides did not refute CNN's reporting that offsets have yet to be purchased.
Clinton has made clean energy a key part of her 2016 campaign platform and a Clinton aide said in July that the campaign "will be carbon neutral."
"We'll be offsetting the carbon footprint of the campaign and that includes travel," the aide said. Outlets, namely The Daily Mail, reported that Clinton flew private during the rollout of her clean energy plan.
On Monday, Josh Schwerin, a Clinton campaign spokesman, said that "offsetting our carbon footprint is still an important goal for this campaign."
"We will be taking steps to meet this goal," Schwerin added.
The most common way to achieve carbon neutrality is by buying voluntary carbon offsets that make up for things like private air travel and driving.
Companies like 3Degrees, Carbon Solutions Group and Direct Energy
, among others, are the most common third-party, carbon offset markets.
There are other ways for companies and campaigns to achieve carbon neutrality. They include planting trees, counting clean commuting and making changes in an office environment. But those are far less common and effective.
Clinton's 2008 presidential campaign also pledged to go carbon neutral
and did so by purchasing carbon offsets from Native Energy, as well as a host of other measures.
Native Energy does not appear on Clinton's recent FEC reports.
In July she said, as president, she would put the United States on a path toward generating enough renewable energy to power every home in the country by 2027 -- ten years after she would hypothetically take office.
Clinton's plan focuses largely on residential power usage and is buoyed by a focus on solar. By the end of her hypothetical first term as president, Clinton has promised that the United States would have more than 500 million solar panels installed across the country.