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Increasing terrestrial carbon uptake from the 1980s to the 1990s with changes in climate and atmospheric CO 2
Author(s) -
Cao Mingkui,
Prince Stephen D.,
Shugart Hank H.
Publication year - 2002
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2001gb001553
Subject(s) - primary production , environmental science , terrestrial ecosystem , carbon sink , ecosystem , carbon cycle , atmospheric sciences , carbon dioxide in earth's atmosphere , sink (geography) , soil respiration , carbon sequestration , soil carbon , carbon dioxide , climate change , soil water , ecology , soil science , geography , biology , geology , cartography
Atmospheric measurements suggest that the terrestrial carbon sink increased from the 1980s to the 1990s, but the causes of the increase are not well understood yet. In this study we investigated the responses of global net primary production in (NPP), soil heterotrophic respiration (HR), and net ecosystem production (NEP) to atmospheric CO 2 increases and climate variation in the period 1981–1998. Our results show that the unusual climate variability in this period associated with strong warming and El Niño caused high interannual variations in terrestrial ecosystem carbon fluxes; nevertheless NPP and NEP increased consistently from the 1980s to 1990s. Annual global NPP and HR varied with a similar magnitude and contributed about equally to the interannual variations in NEP. Global NEP fluctuated between −0.64 and 1.68 Gt C yr −1 with a mean value of 0.62 Gt C yr −1 , its decadal means increased from 0.23 Gt C yr −1 in the 1980s to 1.10 Gt C yr −1 in the 1990s. Total and vegetation carbon storage increased with increases of NPP, but soil carbon storage declined because of higher HR than litter inputs. The tropics (20°N–20°S) had higher mean NEP than the north (>20°N), however, they contributed similarly to the global NEP increase from the 1980s and 1990s. Our estimated terrestrial ecosystem carbon uptake, in response to climate variation and atmospheric CO 2 increase, accounted for only about 15 to 30% of the total terrestrial carbon sink but contributed 73% of its increase from the 1980s to the 1990s.