Rising temperatures are set to drive up emissions from wildfires, fermenting wetlands, and melting permafrost, but these feedback loops are poorly captured in climate models. Scientists are racing to make sense of these emissions to gauge how much warming may lie ahead.

For decades, climate scientists have issued warnings about positive global warming feedbacks, vicious cycles in the Earth system in which rising temperatures from burning fossil fuels beget more warming. The best tools we have to understand these feedback mechanisms are climate models, which simulate how the atmosphere, oceans, and land will respond under different emissions scenarios. Many feedbacks, like the loss of sea ice as the planet warms, are well-accounted for. Others, such as changes in cloud cover, remain far more uncertain but are still included in models.…