Seeing how ecosystems respond to rising temperatures often requires heating a research plot. Working in the Arctic and other remote areas, scientists often build structures that rely on passive warming from the sun. This approach only warms the research plot by about 1.5 degrees Celsius. Scientists developed an alternative approach that uses modulating venting. The system requires no electrical power for fully autonomous operation. When tested on the coastal tundra of northern Alaska, the chambers doubled the warming achieved by existing approaches.