scholarly journals Role of volcanic forcing on future global carbon cycle

2011 ◽  
Vol 2 (1) ◽  
pp. 133-159
Author(s):  
J. F. Tjiputra ◽  
O. H. Otterå
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
21St Century ◽  
Volcanic Eruptions ◽  
Future Climate Change ◽  
Small Scale ◽  
Carbon Uptake ◽  
Carbon Cycle Model ◽  
Large Volcanic Eruptions

Abstract. Using a fully coupled global climate-carbon cycle model, we assess the potential role of volcanic eruptions on future projection of climate change and its associated carbon cycle feedback. The volcanic-like forcings are applied together with business-as-usual IPCC-A2 carbon emissions scenario. We show that very large volcanic eruptions similar to Tambora lead to short-term substantial global cooling. However, over a long period, smaller but more frequent eruptions, such as Pinatubo, would have a stronger impact on future climate change. In a scenario where the volcanic external forcings are prescribed with a five-year frequency, the induced cooling immediately lower the global temperature by more than one degree before return to the warming trend. Therefore, the climate change is approximately delayed by several decades and by the end of the 21st century, the warming is still below two degrees when compared to the present day period. The cooler climate reduces the terrestrial heterotrophic respiration in the northern high latitude and increases net primary production in the tropics, which contributes to more than 45% increase in accumulated carbon uptake over land. The increased solubility of CO2 gas in seawater associated with cooler SST is offset by reduced CO2 partial pressure gradient between ocean and atmosphere, which results in small changes in net ocean carbon uptake. Similarly, there is nearly no change in the seawater buffer capacity simulated between the different volcanic scenarios. Our study shows that even in the relatively extreme scenario where large volcanic eruptions occur every five-years period, the induced cooling only leads to a reduction of 46 ppmv atmospheric CO2 concentration as compared to the reference projection of 878 ppmv, at the end of the 21st century. With respect to sulphur injection geoengineering method, our study suggest that small scale but frequent mitigation is more efficient than the opposite. Moreover, the longer we delay, the more difficult it would be to counteract climate change.

scholarly journals Role of volcanic forcing on future global carbon cycle

2011 ◽  
Vol 2 (1) ◽  
pp. 53-67 ◽  
Author(s):  
J. F. Tjiputra ◽  
O. H. Otterå
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
21St Century ◽  
Volcanic Eruptions ◽  
Future Climate Change ◽  
Feedback Signal ◽  
Carbon Uptake ◽  
Carbon Cycle Model ◽  
Large Volcanic Eruptions

Abstract. Using a fully coupled global climate-carbon cycle model, we assess the potential role of volcanic eruptions on future projection of climate change and its associated carbon cycle feedback. The volcanic-like forcings are applied together with a business-as-usual IPCC-A2 carbon emissions scenario. We show that very large volcanic eruptions similar to Tambora lead to short-term substantial global cooling. However, over a long period, smaller eruptions similar to Pinatubo in amplitude, but set to occur frequently, would have a stronger impact on future climate change. In a scenario where the volcanic external forcings are prescribed with a five-year frequency, the induced cooling immediately lower the global temperature by more than one degree before it returns to the warming trend. Therefore, the climate change is approximately delayed by several decades, and by the end of the 21st century, the warming is still below two degrees when compared to the present day period. Our climate-carbon feedback analysis shows that future volcanic eruptions induce positive feedbacks (i.e., more carbon sink) on both the terrestrial and oceanic carbon cycle. The feedback signal on the ocean is consistently smaller than the terrestrial counterpart and the feedback strength is proportionally related to the frequency of the volcanic eruption events. The cooler climate reduces the terrestrial heterotrophic respiration in the northern high latitude and increases net primary production in the tropics, which contributes to more than 45 % increase in accumulated carbon uptake over land. The increased solubility of CO2 gas in seawater associated with cooler SST is offset by a reduced CO2 partial pressure gradient between the ocean and the atmosphere, which results in small changes in net ocean carbon uptake. Similarly, there is nearly no change in the seawater buffer capacity simulated between the different volcanic scenarios. Our study shows that even in the relatively extreme scenario where large volcanic eruptions occur every five-years period, the induced cooling leads to a reduction of 46 ppmv atmospheric CO2 concentration as compared to the reference projection of 878 ppmv, at the end of the 21st century.

scholarly journals The African contribution to the global climate-carbon cycle feedback of the 21st century

2008 ◽  
Vol 5 (6) ◽  
pp. 4847-4866 ◽  
Author(s):  
P. Friedlingstein ◽  
P. Cadule ◽  
S. L. Piao ◽  
P. Ciais ◽  
S. Sitch
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
21St Century ◽  
Climate Model ◽  
Global Climate ◽  
Future Climate ◽  
Future Climate Change ◽  
Amazon Forest ◽  
Terrestrial Carbon ◽  
Carbon Cycle Model

Abstract. Future climate change will have impact on global and regional terrestrial carbon balances. The fate of African tropical forests over the 21st century has been investigated through global coupled climate carbon cycle model simulations. Under the SRES-A2 socio-economic CO2 emission scenario of the IPCC, and using the Institut Pierre Simon Laplace coupled ocean-terrestrial carbon cycle and climate model, IPSL-CM4-LOOP, we found that the warming over African ecosystems induces a reduction of net ecosystem productivity, making a 20% contribution to the global climate-carbon cycle positive feedback. However, the African rainforest ecosystem alone makes only a negligible contribution to the overall feedback, much smaller than the one arising from the Amazon forest. This is first because of the two times smaller area of forest in Africa, but also because of the relatively lower local land carbon cycle sensitivity to climate change. This beneficial role of African forests in mitigating future climate change should be taken into account when designing forest conservation policy.

Sensitivity of a coupled climate-carbon cycle model to large volcanic eruptions during the last millennium

Tellus B ◽  
2010 ◽  
Vol 62 (5) ◽  
Author(s):  
Victor Brovkin ◽  
Stephan J. Lorenz ◽  
Johann Jungclaus ◽  
Thomas Raddatz ◽  
Claudia Timmreck ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Volcanic Eruptions ◽  
Last Millennium ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
Large Volcanic Eruptions

scholarly journals Effect of increasing CO2 on the terrestrial carbon cycle

2014 ◽  
Vol 112 (2) ◽  
pp. 436-441 ◽  
Author(s):  
David Schimel ◽  
Britton B. Stephens ◽  
Joshua B. Fisher
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Terrestrial Ecosystems ◽  
Future Climate Change ◽  
Carbon Uptake ◽  
Model Diagnostics ◽  
Terrestrial Carbon ◽  
Terrestrial Carbon Cycle ◽  
New Space ◽  
Improved Model

Feedbacks from the terrestrial carbon cycle significantly affect future climate change. The CO2 concentration dependence of global terrestrial carbon storage is one of the largest and most uncertain feedbacks. Theory predicts the CO2 effect should have a tropical maximum, but a large terrestrial sink has been contradicted by analyses of atmospheric CO2 that do not show large tropical uptake. Our results, however, show significant tropical uptake and, combining tropical and extratropical fluxes, suggest that up to 60% of the present-day terrestrial sink is caused by increasing atmospheric CO2. This conclusion is consistent with a validated subset of atmospheric analyses, but uncertainty remains. Improved model diagnostics and new space-based observations can reduce the uncertainty of tropical and temperate zone carbon flux estimates. This analysis supports a significant feedback to future atmospheric CO2 concentrations from carbon uptake in terrestrial ecosystems caused by rising atmospheric CO2 concentrations. This feedback will have substantial tropical contributions, but the magnitude of future carbon uptake by tropical forests also depends on how they respond to climate change and requires their protection from deforestation.

scholarly journals Sensitivity of a coupled climate-carbon cycle model to large volcanic eruptions during the last millennium

Tellus B ◽  
2010 ◽  
Vol 62 (5) ◽  
pp. 674-681 ◽  
Author(s):  
Victor Brovkin ◽  
Stephan Loren ◽  
Johann Jungclaus ◽  
Thomas Raddatz ◽  
Claudia Timmreck ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Volcanic Eruptions ◽  
Last Millennium ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
Large Volcanic Eruptions

scholarly journals Anthropogenic carbon dynamics in the changing ocean

2010 ◽  
Vol 7 (2) ◽  
pp. 391-415
Author(s):  
J. F. Tjiputra ◽  
K. Assmann ◽  
C. Heinze
Keyword(s):  
Climate Change ◽  
Southern Ocean ◽  
High Latitude ◽  
Future Climate Change ◽  
Carbon Uptake ◽  
Continuous Increase ◽  
Carbon Cycle Model ◽  
Anthropogenic Carbon ◽  
Natural Carbon

Abstract. Long-term response of CO2 fluxes to climate change at the ocean surface and the ocean interior are investigated using a coupled climate-carbon cycle model. This study also presents the first attempt in quantifying the evolution of lateral transport of anthropogenic carbon under future climate change. Additionally, its impact on regional carbon storage and uptake are also evaluated. For the 1850–2100 period, our climate change simulation predicts oceanic uptake of anthropogenic carbon of about 538 Pg C. Another simulation indicates that changes in physical climate alone results in a release of natural carbon of about 22 Pg C. The natural carbon outgassing is attributed to the reduction in solubility and change in wind pattern in the Southern Hemisphere. After the anthropogenic carbon passes through the air-sea interface, it is predominantly transported along the large scale overturning circulation below the surface layer. The spatial variations in the transport patterns in turn influence the evolution of future regional carbon uptake. In the North Atlantic, a slow down in Atlantic Meridional Overturnning Circulation weakens the penetration strength of anthropogenic carbon into the deeper ocean, which leads to the reduced uptake rate in this region. In contrast, more than half of the anthropogenic carbon taken up in the high latitude Southern Ocean region (south of 58° S) are efficiently and continuously exported northward, predominantly into intermediate waters. This peculiar transport mechanism allow continuous increase in future carbon uptake in the high latitude Southern Ocean, where the annual uptake strength could reach 3.5 g C m−2 yr−1, nearly triple the global mean of 1.3 g C m−2 yr−1 by the end of the 21st century. Our study further underlines the key role of the Southern Ocean in controlling long-term future carbon uptake.

scholarly journals The African contribution to the global climate-carbon cycle feedback of the 21st century

2010 ◽  
Vol 7 (2) ◽  
pp. 513-519 ◽  
Author(s):  
P. Friedlingstein ◽  
P. Cadule ◽  
S. L. Piao ◽  
P. Ciais ◽  
S. Sitch
Keyword(s):  
Carbon Cycle ◽  
21St Century ◽  
Climate Model ◽  
Global Climate ◽  
Future Climate Change ◽  
Amazon Forest ◽  
Terrestrial Carbon ◽  
Carbon Cycle Model ◽  
Terrestrial Carbon Cycle ◽  
Carbon Balances

Abstract. Future climate change will have impact on global and regional terrestrial carbon balances. The fate of African tropical forests over the 21st century has been investigated through global coupled climate carbon cycle model simulations. Under the SRES-A2 socio-economic CO2 emission scenario of the IPCC, and using the Institut Pierre Simon Laplace coupled ocean-terrestrial carbon cycle and climate model, IPSL-CM4-LOOP, we found that the warming over African ecosystems induces a reduction of net ecosystem productivity, making a 38% contribution to the global climate-carbon cycle positive feedback. Most of this contribution comes from African grasslands, followed by African savannahs, African tropical forest contributing little to the global climate-carbon feedback. However, the vulnerability of the African rainforest ecosystem is quite large. In contrast, the Amazon forest, despite its lower vulnerability, has a much larger overall contribution due to its 6 times larger extent.

scholarly journals On the Role of Volcanism in Dansgaard-Oeschger Cycles

2020 ◽  
Author(s):  
Johannes Lohmann ◽  
Anders Svensson
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Abrupt Climate Change ◽  
Last Glacial Period ◽  
Large Volcanic Eruptions ◽  
The Last Glacial

Abstract. A significant influence of major volcanic eruptions on regime shifts and long-term climate variability has been suggested previously. But a statistical assessment of this has been hampered by inaccurate synchronization of large volcanic eruptions to changes in past climate. Here, this is achieved by combining a new record of bipolar volcanism from Greenland and Antarctic ice cores with records of abrupt climate change derived from the same ice cores. We show that at > 99 % confidence bipolar volcanic eruptions occurred more frequently than expected by chance just before the onset of Dansgaard-Oeschger events, the most prominent large-scale abrupt climate changes of the last glacial period. Out of 20 climate change events in the 12–60 ka period, 5 (7) occur within 20 (50) years after a bipolar eruption. Thus, such large eruptions may act as short-term triggers for large-scale abrupt climate change, and may explain part of the variability of Dansgaard-Oeschger cycles.

Terrestrial Carbon Cycle Dynamics under Recent and Future Climate Change

2005 ◽  
Vol 18 (10) ◽  
pp. 1609-1628 ◽  
Author(s):  
H. Damon Matthews ◽  
Andrew J. Weaver ◽  
Katrin J. Meissner
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Future Climate ◽  
First Century ◽  
Future Climate Change ◽  
Cycle Model ◽  
Terrestrial Carbon ◽  
Carbon Cycle Model ◽  
Terrestrial Carbon Cycle ◽  
Twenty First Century

Abstract The behavior of the terrestrial carbon cycle under historical and future climate change is examined using the University of Victoria Earth System Climate Model, now coupled to a dynamic terrestrial vegetation and global carbon cycle model. When forced by historical emissions of CO2 from fossil fuels and land-use change, the coupled climate–carbon cycle model accurately reproduces historical atmospheric CO2 trends, as well as terrestrial and oceanic uptake for the past two decades. Under six twenty-first-century CO2 emissions scenarios, both terrestrial and oceanic carbon sinks continue to increase, though terrestrial uptake slows in the latter half of the century. Climate–carbon cycle feedbacks are isolated by comparing a coupled model run with a run where climate and the carbon cycle are uncoupled. The modeled positive feedback between the carbon cycle and climate is found to be relatively small, resulting in an increase in simulated CO2 of 60 ppmv at the year 2100. Including non-CO2 greenhouse gas forcing and increasing the model’s climate sensitivity increase the effect of this feedback to 140 ppmv. The UVic model does not, however, simulate a switch from a terrestrial carbon sink to a source during the twenty-first century, as earlier studies have suggested. This can be explained by a lack of substantial reductions in simulated vegetation productivity due to climate changes.

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