Study Finds Warmer Growing Seasons Don't Boost Forest Carbon Absorption as Expected

A new study published in Science challenges the assumption that longer growing seasons from global warming will increase forests' ability to absorb CO2. Researchers analyzed over 50,000 wood samples from conifer forests across four continents and found that growth rate, not season length, determines wood production. Above an average annual temperature of 6°C, cell production declines, likely due to water scarcity, meaning drought can offset any benefits of a longer season. The findings suggest that boreal forests may initially benefit from warming, but temperate and Mediterranean forests could see reduced carbon uptake. This has implications for carbon accounting and forest-based mitigation strategies. As climate models incorporate these results, we may need to lower expectations for natural carbon sinks and focus more on direct emissions reductions.