Warming climate extends dryness-controlled areas of terrestrial carbon sequestration

• Published in: Scientific reports 2014-07, Vol.4 (1), p.5472, Article 5472
• Main Authors: Yi, Chuixiang, Wei, Suhua, Hendrey, George
• Format: Article
• Language: English
• Subjects: 704/106/694/1108; 704/106/694/682; Carbon dioxide; Carbon sequestration; Climate; Climate change; Feedback; Global warming; Humanities and Social Sciences; multidisciplinary; Science; Temperature effects; Vegetation
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep05472

At biome-scale, terrestrial carbon uptake is controlled mainly by weather variability. Observational data from a global monitoring network indicate that the sensitivity of terrestrial carbon sequestration to mean annual temperature ( T ) breaks down at a threshold value of 16°C, above which terrestrial CO 2 fluxes are controlled by dryness rather than temperature. Here we show that since 1948 warming climate has moved the 16°C T latitudinal belt poleward. Land surface area with T > 16°C and now subject to dryness control rather than temperature as the regulator of carbon uptake has increased by 6% and is expected to increase by at least another 8% by 2050. Most of the land area subjected to this warming is arid or semiarid with ecosystems that are highly vulnerable to drought and land degradation. In areas now dryness-controlled, net carbon uptake is ~27% lower than in areas in which both temperature and dryness ( T < 16°C) regulate plant productivity. This warming-induced extension of dryness-controlled areas may be triggering a positive feedback accelerating global warming. Continued increases in land area with T > 16°C has implications not only for positive feedback on climate change, but also for ecosystem integrity and land cover, particularly for pastoral populations in marginal lands.