Earlier this year, John Sylvan said he regretted inventing Keurig coffee cups, the wildly popular instant coffee brewing empire that also happens to be not very good for the environment. Given the creator's unflattering views of his own brainchild, it's no surprise that Keurig sales are down 23 percent. It also appears that consumers were put off by the new Keurig 2.0 device, which wasn't designed for My K-Cup refillable pods, a known cost-saver that allows consumers to use any type of coffee and not be limited to Keurig-authorized brands.

"Quite honestly, we were wrong," Keurig president and CEO Brian Kelley said during a recent earnings call. "We underestimated the passion the consumer had for this. We missed it. We shouldn't have taken it away. We're bringing it back."

The old, refillable pods will still not work with the new Keurig 2.0 machines, according to Mashable, so consumers will still have to buy new, reusable pods.

In addition to being cheaper, the refillable pods are also better for the planet, as billions of K-Cups end up in landfills every year. Though it's possible to recycle K-Cups, the process is complicated and requires consumers to disassemble them. Plus, it seems like most consumers are not even aware that they can even recycle K-Cups. The result is that they end up in landfills.

It's estimated that the amount of K-Cups purchased last year alone could circle the world more than a dozen times. ​​In January, Eggs Studio CEO Mike Hachey created a short video titled "Kill the K-Cup" to playfully, but seriously highlight their effect on the environment:

"If you ever find yourself throwing out a K-Cup, and then you remember that 13 billion went into landfills last year, do you feel okay contributing to that?" Hachey said in an interview with The Atlantic. "That's what it comes down to."

Green Mountain, a Keurig-owned coffee company that produces K-Cups and boasts a dedication to sustainability, aims to put a fully recyclable K-Cup on the market by 2020. As ATTN: pointed out in March, though, a lot more damage could be done in the next five years thanks to K-Cups winding up in landfills.

Sylvan, who was bought out of Keurig eight years ago, told The Atlantic that he's not convinced K-Cups will ever be easily recyclable. 

“No matter what they say about recycling, those things will never be recyclable," he said.