A new paper in Environmental Research Letters finds emissions of methane and carbon dioxide from thawing permafrost, drying wetlands and lakes, warming freshwaters, and fiercer wildfires could amplify human-driven warming by about 20 to 30 percent, adding roughly 0.2C to 0.4C to global average temperature by the end of this century. The study’s lead author Sam Abernethy of Spark Climate Solutions Research warned this “hidden multiplier” is missing from the climate models that inform policy, so those models likely underestimate future warming and overestimate how much carbon humans can still emit. Co-author Rob Jackson of Stanford University said the disruption of the world’s carbon cycles is now visible in real time and urged that these feedbacks be included in the next generation of climate policies. The paper analyzed four broad natural sources of emissions, permafrost, wetlands, freshwaters, and wildfire-impacted forests and soils, and concluded current projections largely omit their future contributions. The authors note that cutting fossil fuel pollution will still reduce the amount of additional emissions those landscapes produce. The United Nations last week acknowledged the global temperature rise to 1.5C above pre-industrial levels will be breached in the next few years, a context the paper says makes accounting for these feedbacks more urgent.
