CLIMATE CHANGE AND CARBON CYCLE PERTURBATIONS IN THE NORWEGIAN-GREENLAND SEAWAY DURING THE LATEST JURASSIC AND EARLY CRETACEOUS

The increase in atmospheric CO2 driven by anthropogenic emissions is the main radiative forcing causing climate change. But this increase is not only a result from emissions, but also from changes in the global carbon cycle. These changes arise from feedbacks between climate and the carbon cycle that drive CO2 into or out of the atmosphere in addition to the emissions, thereby either accelerating or buffering climate change. Therefore, understanding the contribution of these feedbacks to the global response of the carbon cycle is crucial in advancing climate research. Currently, this contribution is quantified by the &#945;-&#946;-&#947; framework (Friedlingstein et al., 2003). But this quantification is only valid for a particular perturbation scenario and time period. In contrast, a recently proposed generalization (Rubino et al., 2016) of this framework for weak perturbations quantifies this contribution for all scenarios and at different time scales.&#160;Thereby, this generalization provides a systematic framework to investigate the response of the global carbon cycle in terms of the climate-carbon cycle feedbacks. In the present work we employ this framework to study these feedbacks and the airborne fraction in different CMIP5 models. We demonstrate (1) that this generalization of the &#945;-&#946;-&#947; framework consistently describes the linear dynamics of the carbon cycle in the MPI-ESM; and (2) how by this framework the climate-carbon cycle feedbacks and airborne fraction are quantified at different time scales in CMIP5 models. Our analysis shows that, independently of the perturbation scenario, (1) the net climate-carbon cycle feedback is negative at all time scales; (2) the airborne fraction generally decreases for increasing time scales; and (3) the land biogeochemical feedback dominates the model spread in the airborne fraction at all time scales. This last result therefore emphasizes the need to improve our understanding of this particular feedback.References:P. Friedlingstein, J.-L. Dufresne, P. Cox, and P. Rayner. How positive is the feedback between climate change and the carbon cycle? Tellus B, 55(2):692&#8211;700, 2003.M. Rubino, D. Etheridge, C. Trudinger, C. Allison, P. Rayner, I. Enting, R. Mulvaney, L. Steele, R. Langenfelds, W. Sturges, et al. Low atmospheric CO2 levels during the Little Ice Age due to cooling-induced terrestrial uptake. Nature Geoscience, 9(9):691&#8211;694, 2016.

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Scaled biotic disruption during early Eocene global warming events

Biogeosciences ◽

10.5194/bg-9-4679-2012 ◽

2012 ◽

Vol 9 (11) ◽

pp. 4679-4688 ◽

Cited By ~ 30

Author(s):

S. J. Gibbs ◽

P. R. Bown ◽

B. H. Murphy ◽

A. Sluijs ◽

K. M. Edgar ◽

...

Keyword(s):

Climate Change ◽

Carbon Cycle ◽

Threshold Value ◽

Early Eocene ◽

Natural Experiments ◽

Thermal Maximum ◽

Carbon Release ◽

Long Time ◽

Extinction Events ◽

The Relationship

Abstract. Late Paleocene and early Eocene hyperthermals are transient warming events associated with massive perturbations of the global carbon cycle, and are considered partial analogues for current anthropogenic climate change. Because the magnitude of carbon release varied between the events, they are natural experiments ideal for exploring the relationship between carbon cycle perturbations, climate change and biotic response. Here we quantify marine biotic variability through three million years of the early Eocene that include five hyperthermals, utilizing a method that allows us to integrate the records of different plankton groups through scenarios ranging from background to major extinction events. Our long time-series calcareous nannoplankton record indicates a scaling of biotic disruption to climate change associated with the amount of carbon released during the various hyperthermals. Critically, only the three largest hyperthermals, the Paleocene–Eocene Thermal Maximum (PETM), Eocene Thermal Maximum 2 (ETM2) and the I1 event, show above-background variance, suggesting that the magnitude of carbon input and associated climate change needs to surpass a threshold value to cause significant biotic disruption.

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Carbon Cycle in the North Pacific in terms of Climate Change

Oceanography in Japan ◽

10.5928/kaiyou.13.347 ◽

2004 ◽

Vol 13 (4) ◽

pp. 347-356

Author(s):

Tsuneo Ono

Keyword(s):

Climate Change ◽

Carbon Cycle ◽

North Pacific ◽

The North ◽

The North Pacific

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Role of volcanic forcing on future global carbon cycle

Earth System Dynamics Discussions ◽

10.5194/esdd-2-133-2011 ◽

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.

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The role of forests in the carbon cycle and in climate change

Climate Change ◽

10.1016/b978-0-12-821575-3.00027-x ◽

2021 ◽

pp. 561-579

Author(s):

Matthew D. Hurteau

Keyword(s):

Climate Change ◽

Carbon Cycle

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Introduction

The Phanerozoic Carbon Cycle ◽

10.1093/oso/9780195173338.003.0003 ◽

2004 ◽

Author(s):

Robert A. Berner

Keyword(s):

Climate Change ◽

Carbon Dioxide ◽

Carbon Cycle ◽

Global Climate ◽

Geological Time ◽

Short Term ◽

Quaternary Period ◽

Geological Time Scale ◽

The Earth

The cycle of carbon is essential to the maintenance of life, to climate, and to the composition of the atmosphere and oceans. What is normally thought of as the “carbon cycle” is the transfer of carbon between the atmosphere, the oceans, and life. This is not the subject of interest of this book. To understand this apparently confusing statement, it is necessary to separate the carbon cycle into two cycles: the short-term cycle and the long-term cycle. The “carbon cycle,” as most people understand it, is represented in figure 1.1. Carbon dioxide is taken up via photosynthesis by green plants on the continents or phytoplankton in the ocean. On land carbon is transferred to soils by the dropping of leaves, root growth, and respiration, the death of plants, and the development of soil biota. Land herbivores eat the plants, and carnivores eat the herbivores. In the oceans the phytoplankton are eaten by zooplankton that are in turn eaten by larger and larger organisms. The plants, plankton, and animals respire CO2. Upon death the plants and animals are decomposed by microorganisms with the ultimate production of CO2. Carbon dioxide is exchanged between the oceans and atmosphere, and dissolved organic matter is carried in solution by rivers from soils to the sea. This all constitutes the shortterm carbon cycle. The word “short-term” is used because the characteristic times for transferring carbon between reservoirs range from days to tens of thousands of years. Because the earth is more than four billion years old, this is short on a geological time scale. As the short-term cycle proceeds, concentrations of the two principal atmospheric gases, CO2 and CH4, can change as a result of perturbations of the cycle. Because these two are both greenhouse gases—in other words, they adsorb outgoing infrared radiation from the earth surface—changes in their concentrations can involve global warming and cooling over centuries and many millennia. Such changes have accompanied global climate change over the Quaternary period (past 2 million years), although other factors, such as variations in the receipt of solar radiation due to changes in characteristics of the earth’s orbit, have also contributed to climate change.

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