Variations in carbon exchange between terrestrial ecosystems and the atmosphere due to CO{sub 2} evaluation and climate change
The global carbon budget for atmospheric CO{sub 2} can`t been balanced, a sink of 1 to 3 Gt C yr{sup -1} has not yet been clearly identified. Without a good account for the fate of the miss carbon, prediction of future atmospheric CO{sub 2} concentration and climate change will remain uncertain. It is suggested that terrestrial ecosystems may take up the miss carbon. To validate this hypothesis and to improve the estimates of the carbon sink or source strength requires a direct investigation of the carbon exchange of terrestrial ecosystems and its response to atmospheric CO{sub 2} elevation and climate change at the global scale. In this study, a highly aggregated model was developed on the basis of photosynthesis, plant growth, litter production and soil organic carbon decomposition. And the model was use to predict the variations in carbon fluxes between terrestrial ecosystems and the atmosphere from 1860 to 2020. In our estimates, climate change alone does not cause a significant variation in net primary production (NPP), but results in a reduction in net ecosystem production (NEP) by 50% thus, a decrease in the total carbon storage, since 1960s. Climate change happened undercuts the capacity of terrestrial ecosystems taking up atmospheric CO{sub 2}. Without climate change, CO{sub 2} elevation enhances NPP and NEP steadily. NPP is enhanced by 26% and NEP is increased from about 1.0 Gt C yr{sup -1} in 1860s to 4.0 Gt C yr{sup -1} in 2020s. The combined CO{sub 2} elevation and climate change increase the global annual NPP from 46.0 Gt C in 1860s to 57.0 Gt C in 2010s. NEP is increased to 2.1 Gt C yr{sup -1} in 1980s and about 3.6 Gt C yr{sup -1} in 2010s. The increase occurs in both the northern middle-high latitudes and tropical regions. Taking land use change into account, terrestrial ecosystems are nearly carbon-balanced before 1950s, but afterwards they become a significant sink of about 1.6 Gt C yr{sup -1} for atmospheric CO{sub 2}.
- OSTI ID:
- 577234
- Report Number(s):
- CONF-970522--
- Country of Publication:
- United States
- Language:
- English
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