This week, Colorado’s Rep. Mike Coffman became the 18th Republican to join the bipartisan House Climate Solutions Caucus. New Hampshire’s Rep. Annie Kuster was his Democratic partner.

“I am pleased to be joining this caucus with my colleague, Representative Kuster,” Coffman said. “It’s clear that we should do all we can to reduce carbon emissions in order to improve the quality of our environment, and I believe that Ms. Kuster and I can bring a true bi-partisan spirit to working toward common-sense solutions to environmental issues. I look forward to working with the Climate Solutions Caucus to craft and advance policies that keep our environment clean while keeping our economy and the American innovative spirit strong.”

The caucus, which has swelled to 36 members, adheres to a “Noah’s Ark” rule of admitting Republican and Democrats in even numbers.