Recent decrease of the impact of tropical temperature on the carbon cycle linked to increased precipitation
International audience Abstract The atmospheric CO 2 growth rate (CGR) variability is largely controlled by tropical temperature fluctuations. The sensitivity of CGR to tropical temperature $$\left({{{{\rm{\gamma }}}}}_{{{{\rm{CGR}}}}}^{{{{\rm{T}}}}}\right)$$ γ CGR T has strongly increased since 196...
Published in: | Nature Communications |
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Main Authors: | , , , , , , , , |
Other Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2023
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Subjects: | |
Online Access: | https://hal.science/hal-04042312 https://hal.science/hal-04042312/document https://hal.science/hal-04042312/file/s41467-023-36727-2.pdf https://doi.org/10.1038/s41467-023-36727-2 |
Summary: | International audience Abstract The atmospheric CO 2 growth rate (CGR) variability is largely controlled by tropical temperature fluctuations. The sensitivity of CGR to tropical temperature $$\left({{{{\rm{\gamma }}}}}_{{{{\rm{CGR}}}}}^{{{{\rm{T}}}}}\right)$$ γ CGR T has strongly increased since 1960, but here we show that this trend has ceased. Here, we use the long-term CO 2 records from Mauna Loa and the South Pole to compute CGR, and show that $${{{{\rm{\gamma }}}}}_{{{{\rm{CGR}}}}}^{{{{\rm{T}}}}}$$ γ CGR T increased by 200% from 1960–1979 to 1979–2000 but then decreased by 117% from 1980–2001 to 2001–2020, almost returning back to the level of the 1960s. Variations in $${{{{\rm{\gamma }}}}}_{{{{\rm{CGR}}}}}^{{{{\rm{T}}}}}$$ γ CGR T are significantly correlated with changes in precipitation at a bi-decadal scale. These findings are further corroborated by results from a dynamic vegetation model, collectively suggesting that increases in precipitation control the decreased $${{{{\rm{\gamma }}}}}_{{{{\rm{CGR}}}}}^{{{{\rm{T}}}}}$$ γ CGR T during recent decades. Our results indicate that wetter conditions have led to a decoupling of the impact of the tropical temperature variation on the carbon cycle. |
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