On April 22, with the celebration of Earth Day, Allbirds will release an open-source version of its Carbon Footprint Calculator on Freethefootprint.com. “For too long, many brands have focused on marketing sustainability rather than actually implementing holistic, high-impact solutions — and to an extent, it’s worked,” said Joey Zwillinger, co-founder and co-CEO of the Californian brand of sustainable footwear, in a statement. “If we want to continue pushing fashion toward a more sustainable future, we need brands to take responsibility for what they share with consumers. Having a key, universal identifier like Carbon Footprint to evaluate sustainability claims and force accountability from businesses is critical to drowning out the noise,” he added. Allbirds is urging consumers to force the fashion industry to add carbon footprint labels to their products and sign a pledge available on the petition website Change.org.