Amazon is handling a rapidly growing number of returns that are causing a massive problem for the e-commerce giant and the planet.

A National Retail Federation survey found a record $761 billion of merchandise was returned to retailers in 2021. That amount surpasses what the U.S. spent on national defense in 2021, which was $741 billion.

Amazon wouldn’t share its overall returns numbers, but in 2021, the National Retail Federation estimates 16.6% of all merchandise sold during the holiday season was returned, up more than 56% from the year before. For online purchases, the average rate of return was even higher, at nearly 21%, up from 18% in 2020. With $469 billion of net sales revenue last year, Amazon’s returns numbers are likely staggering.

U.S. returns generate 16 million metric tons of carbon emissions during their complicated reverse journey and up to 5.8 billion pounds of landfill waste each year, according to returns solution provider Optoro