cross-posted from: https://slrpnk.net/post/27610583

• Tropical forests exchange more CO2 with the atmosphere than any other terrestrial biome, meaning that even a relatively small shift in the balance of carbon uptake and release there could have a big impact on global climate. Despite this, research on tropical soil responses to warming has lagged behind.
• In a field experiment in Puerto Rico, researchers used infrared heaters to warm understory plants and topsoil by 4° Celsius. Warming significantly increased soil carbon emissions, but terrain also had a major impact: A warmed plot at the top of a slope showed an unprecedented 204% increase in CO2 emissions after one year.
• Carbon emissions from plots lower on the slope increased between 42% and 59% in response to warming — in line with the results from the only other long-term tropical soil warming experiment to date. However, the upper-slope response represents the largest change in any soil warming experiment conducted globally.
• The new study results add to a growing body of evidence that tropical soils are far more sensitive to warming than previously thought. If elevated tropical soil CO2 releases persist in the long term, it could have dire consequences for Earth’s climate. But the soil biome may adjust over time, so future effects remain unclear.

archived (Wayback Machine):

• Mongabay article
• research cited