Terrestrial carbon sink in the Northern Hemisphere estimated from the atmospheric CO2 difference between Mauna Loa and the South Pole since 1959

Abstract. The terrestrial biosphere is currently acting as a net carbon sink on the global scale, exhibiting significant interannual variability in strength. To reliably predict the future strength of the land sink and its role in atmospheric CO2 growth, the underlying biogeochemical processes and their response to a changing climate need to be well understood. In particular, better knowledge of the impact of key climate variables such as temperature or precipitation on the biospheric carbon reservoir is essential. It is demonstrated using nearly a decade of SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) nadir measurements that years with higher temperatures during the growing season can be robustly associated with larger growth rates in atmospheric CO2 and smaller seasonal cycle amplitudes for northern mid-latitudes. We find linear relationships between warming and CO2 growth as well as seasonal cycle amplitude at the 98% significance level. This suggests that the terrestrial carbon sink is less efficient at higher temperatures during the analysed time period. Unless the biosphere has the ability to adapt its carbon storage under warming conditions in the longer term, such a temperature response entails the risk of potential future sink saturation via a positive carbon-climate feedback. Quantitatively, the covariation between the annual CO2 growth rates derived from SCIAMACHY data and warm season surface temperature anomaly amounts to 1.25 ± 0.32 ppm yr−1 K−1 for the Northern Hemisphere, where the bulk of the terrestrial carbon sink is located. In comparison, this relationship is less pronounced in the Southern Hemisphere. The covariation of the seasonal cycle amplitudes retrieved from satellite measurements and temperature anomaly is −1.30 ± 0.31 ppm K−1 for the north temperate zone. These estimates are consistent with those from the CarbonTracker data assimilated CO2 data product, indicating that the temperature dependence of the model surface fluxes is realistic.

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Terrestrial carbon sink observed from space: variation of growth rates and seasonal cycle amplitudes in response to interannual surface temperature variability

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-22733-2013 ◽

2013 ◽

Vol 13 (8) ◽

pp. 22733-22755 ◽

Cited By ~ 1

Author(s):

O. Schneising ◽

M. Reuter ◽

M. Buchwitz ◽

J. Heymann ◽

H. Bovensmann ◽

...

Keyword(s):

Surface Temperature ◽

Growth Rates ◽

Seasonal Cycle ◽

Temperature Anomaly ◽

Carbon Sink ◽

Atmospheric Co2 ◽

Climate Feedback ◽

Terrestrial Carbon ◽

Terrestrial Carbon Sink ◽

The Impact

Abstract. The terrestrial biosphere is currently acting as a net carbon sink on the global scale exhibiting significant interannual variability in strength. To reliably predict the future strength of the land sink and its role in atmospheric CO2 growth the underlying processes and their response to a changing climate need to be well understood. In particular, better knowledge of the impact of key climate variables like temperature or precipitation on the biospheric carbon reservoir is essential. It is demonstrated using nearly a decade of SCIAMACHY nadir measurements that years with higher temperatures during the growing season can be robustly associated with larger growth rates in atmospheric CO2 and smaller seasonal cycle amplitudes for northern mid-latitudes. We find linear relationships between warming and CO2 growth as well as seasonal cycle amplitude at the 98% significance level. This suggests that the terrestrial carbon sink is less efficient at higher temperatures, which might lead to future sink saturation via a positive carbon-climate feedback. Quantitatively, the covariation between the annual CO2 growth rates derived from SCIAMACHY data and warm season surface temperature anomaly amounts to 1.25±0.32 ppm yr−1 K−1 for the Northern Hemisphere where the bulk of the terrestrial carbon sink is located. In comparison, the relation is less pronounced in the Southern Hemisphere. The covariation of the seasonal cycle amplitudes derived from satellite and temperature anomaly is −1.30±0.31 ppm K−1 for the north temperate zone. These estimates are consistent with those from the CarbonTracker data assimilated CO2 data product indicating that the temperature dependence of the model surface fluxes is realistic.

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Faculty Opinions recommendation of Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.738493089.793584419 ◽

2021 ◽

Author(s):

Douglas Frank

Keyword(s):

Carbon Sink ◽

Atmospheric Co2 ◽

Terrestrial Carbon ◽

Terrestrial Carbon Sink

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Drivers of Multicentury Trends in the Atmospheric CO<sub>2</sub> Mean Annual Cycle in a Prognostic ESM

10.5194/bg-2016-112 ◽

2016 ◽

Author(s):

Jessica Liptak ◽

Gretchen Keppel-Aleks ◽

Keith Lindsay

Keyword(s):

Climate Change ◽

Annual Cycle ◽

Carbon Sink ◽

Growing Season ◽

Atmospheric Co2 ◽

High Latitudes ◽

Terrestrial Carbon ◽

Cycle Amplitude ◽

Amplitude Increase ◽

Terrestrial Carbon Sink

Abstract. The amplitude of the mean annual cycle of atmospheric CO2 has increased by at least 0.5 % yr−1 over most of the Northern Hemisphere (NH) extratropics during the last three decades likely from a combination of enhanced atmospheric CO2, climate change, and anthropogenic land use change. We investigated how each of these factors affected the increase in the atmospheric CO2 mean annual cycle amplitude simulated by the Community Earth System Model (CESM), a prognostic coupled climate- carbon cycle model. The simulated amplitude of the NH mean CO2 annual cycle showed a weaker trend than observed, increasing by only 15 % over the period spanning 1950–2010. By 2100, the amplitude rose to 57 % above the present-day baseline (1950–1959), and reached a maximum of 76 % above the baseline around 2250. The amplitude increase in the CESM was mainly driven by climate change and changing atmospheric composition, with the largest amplitude gains occurring in the mid- and high latitudes. In addition, the long-term simulations revealed shifts in key climate drivers of the atmospheric CO2 seasonality that were not apparent before 2100. Climate change from NH boreal ecosystems was the largest driver of Arctic CO2 annual cycle amplification between 1950 and 2100. CO2 fertilization and nitrogen deposition in the NH boreal and temperate ecosystems contributed the most to the amplitude increase over the midlatitudes through 2300 and over the Arctic after 2100. Greater terrestrial productivity during the growing season contributed the most to the annual cycle amplification over the high latitudes, midlatitudes, and the NH tropics, reflecting lengthening of the growing season rather than the strength of the terrestrial carbon sink. Prior to 2100, CO2 annual cycle amplification occurred in conjunction with an increase in the NH land carbon sink, but the trends decoupled after 2100, underscoring that an increasing atmospheric CO2 annual cycle amplitude is not predicated on a strengthened terrestrial carbon sink.

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Sensitivity of Holocene atmospheric CO<sub>2</sub> and the modern carbon budget to early human land use: analyses with a process-based model

Biogeosciences ◽

10.5194/bg-8-69-2011 ◽

2011 ◽

Vol 8 (1) ◽

pp. 69-88 ◽

Cited By ~ 79

Author(s):

B. D. Stocker ◽

K. Strassmann ◽

F. Joos

Keyword(s):

Land Use ◽

Late Holocene ◽

Carbon Sink ◽

Ice Cores ◽

Atmospheric Co2 ◽

Terrestrial Carbon ◽

Dynamic Global Vegetation Model ◽

Human Land Use ◽

Terrestrial Carbon Sink ◽

The Impact

Abstract. A Dynamic Global Vegetation model coupled to a simplified Earth system model is used to simulate the impact of anthropogenic land cover changes (ALCC) on Holocene atmospheric CO2 and the contemporary carbon cycle. The model results suggest that early agricultural activities cannot explain the mid to late Holocene CO2 rise of 20 ppm measured on ice cores and that proposed upward revisions of Holocene ALCC imply a smaller contemporary terrestrial carbon sink. A set of illustrative scenarios is applied to test the robustness of these conclusions and to address the large discrepancies between published ALCC reconstructions. Simulated changes in atmospheric CO2 due to ALCC are less than 1 ppm before 1000 AD and 30 ppm at 2004 AD when the HYDE 3.1 ALCC reconstruction is prescribed for the past 12 000 years. Cumulative emissions of 69 GtC at 1850 and 233 GtC at 2004 AD are comparable to earlier estimates. CO2 changes due to ALCC exceed the simulated natural interannual variability only after 1000 AD. To consider evidence that land area used per person was higher before than during early industrialisation, agricultural areas from HYDE 3.1 were increased by a factor of two prior to 1700 AD (scenario H2). For the H2 scenario, the contemporary terrestrial carbon sink required to close the atmospheric CO2 budget is reduced by 0.5 GtC yr−1. Simulated CO2 remains small even in scenarios where average land use per person is increased beyond the range of published estimates. Even extreme assumptions for preindustrial land conversion and high per-capita land use do not result in simulated CO2 emissions that are sufficient to explain the magnitude and the timing of the late Holocene CO2 increase.

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Atmospheric CO2 Exchange With the Biosphere and the Ocean

Radiocarbon ◽

10.1017/s0033822200012091 ◽

1989 ◽

Vol 31 (03) ◽

pp. 503-509 ◽

Cited By ~ 1

Author(s):

Roger Bergh ◽

Reidar Nydal

Keyword(s):

Mixed Layer ◽

Deep Ocean ◽

Co2 Exchange ◽

Time Dependent ◽

Atmospheric Co2 ◽

South Pole ◽

Ocean Mixed Layer ◽

The South ◽

Mauna Loa

We model the exchange of carbon between the different reservoirs (atmosphere, ocean mixed layer, deep ocean and biosphere). The influence of the biosphere is investigated using two extreme assumptions: 1) no net biospheric effect and 2) biospheric uptake of CO2 proportional to the atmospheric content of CO2 and time-dependent deforestation. Observations of atmospheric CO2 at Mauna Loa and the South Pole may be fit by both these assumptions.

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