Uncertainty quantification of the multi-centennial response  of the Antarctic ice sheet to climate change

Bulthuis, Kevin; Arnst, Maarten; Sun, Sainan; Pattyn, Frank

doi:10.5194/tc-13-1349-2019

Cited by 89 publications

(162 citation statements)

References 115 publications

(209 reference statements)

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“…Under RCP2.6, DeConto and Pollard's modeling experiment produced virtually no net Antarctic contribution to global mean sea level by 2100, with only a 20 cm rise by 2500. Another study found that the RCP2.6 scenario prevented collapse of the WAIS regardless of uncertainties in model parameters (Bulthuis et al, 2019).…”

Section: Commitment To Loss Of the Greenland And West Antarctic Ice Smentioning

confidence: 99%

ESD Reviews: mechanisms, evidence, and impacts of climate tipping elements

Wang

Hausfather

2020

Preprint

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Abstract. Increasing attention is focusing upon climate tipping elements – large-scale earth systems anticipated to respond through positive feedbacks to anthropogenic climate change by shifting towards new long-term states. In some but not all cases, such changes could produce additional greenhouse gas emissions or radiative forcing that could compound global warming. Developing greater understanding of tipping elements is important for predicting future climate risks. Here we review mechanisms, predictions, impacts, and knowledge gaps associated with ten notable climate tipping elements. We also evaluate which tipping elements are more imminent and whether shifts will likely manifest rapidly or over longer timescales. Some tipping elements are significant to future global climate and will likely affect major ecosystems, climate patterns, and/or carbon cycling within the current century. However, assessments under different emissions scenarios indicate a strong potential to reduce or avoid impacts associated with many tipping elements through climate change mitigation. Most tipping elements do not possess the potential for abrupt future change within years, and some tipping elements are perhaps more accurately termed climate feedbacks. Nevertheless, significant uncertainties remain associated with many tipping elements, highlighting an acute need for further research and modeling to better constrain risks.

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Section: Commitment To Loss Of the Greenland And West Antarctic Ice Smentioning

confidence: 99%

ESD Reviews: mechanisms, evidence, and impacts of climate tipping elements

Wang

Hausfather

2020

Preprint

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“…All climate model parameter sets yield climate simulations in agreement with observations over the past 500 years (Loutre et al, 2011). Model parameter set P22 is chosen for the multi-millennial integrations because of its mid-range contribution to sea-level at 2100 AD and 2300 AD in comparison with recent studies Calov et al, 2018;Bulthuis et al, 2019; Tables S1-S2 and Figure S1). The mean annual temperature anomalies over the ice sheets for 2070-2100 relative to 1970-2005 (+4.6˚C over Greenland and +3.8 ˚C over Antarctica for 120 RCP8.5) correspond well with the mid to upper ranges of AOGCM projections over the polar regions (Fettweis et al, 2013, Barthel et al, 2019.…”

Section: Model Description and Initialisationmentioning

confidence: 83%

Semi-equilibrated global sea-level change projections for the next 10 000 years

Breedam¹,

Goelzer²,

Huybrechts³

2020

Preprint

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The emphasis for informing policy makers on future sea-level rise has been on projections by the end of the 21 st century. However, due to the long lifetime of atmospheric CO2, the thermal inertia of the climate system and the slow equilibration of the ice sheets, global sea level will continue to rise on a multi-millennial timescale even when anthropogenic CO2 emissions cease completely during the coming decades to centuries. Here we present global sea-level change projections 25 due to melting of land ice combined with steric sea effects during the next 10,000 years calculated in a fully interactive way with the Earth System Model of Intermediate Complexity LOVECLIMv1.3. The climate forcing is based on the Extended Concentration Pathways defined until 2300 AD with no carbon dioxide emissions thereafter and the inclusion of a methaneemission feedback for the highest forcing scenario, equivalent to a cumulative CO2 release of around 460 to 5800 GtC. After 10,000 years, the sea-level change rate drops below 0.05 m per century and a semi-equilibrated state is reached. The Greenland 30 ice sheet is found to nearly disappear for all forcing scenarios. The Antarctic ice sheet contributes only about 1.6 m to sea level for the lowest forcing scenario with a limited retreat of the grounding line in West Antarctica. For the higher forcing scenarios, the marine basins of the East Antarctic ice sheet also become ice free, resulting in a sea-level rise of up to 27 m. The global mean sea-level change after 10,000 years ranges from 9.2 m to more than 37 m. The projections of multi-millennial semiequilibrated sea-level rise for a given CO2 forcing are shown to be in good agreement with geological archives. 35 45 from 10,000 years for accumulation rate changes to up to 100,000 years for temperature changes for the Antarctic ice sheet (Alley and Whillans, 1984).On a multi-millennial timescale, changes in land ice volume (mass contribution) together with ocean density changes from thermal expansion (thermosteric contribution) and haline contraction (halosteric contribution) are the main components contributing to global sea-level change (Miller et al., 2005). The mass contribution comes from melting or growing of the 50 Antarctic ice sheet, the Greenland ice sheet and glaciers and ice caps. The steric contribution is the expansion of ocean water when it gets warmer and less saline or conversely, the contraction when water is cooling and gets more salty (Feistel, 2010).The magnitude of thermal expansion depends on the climatic temperature forcing and on the rate of oceanic heat uptake.Because of the large mass and slow turnover time of the deep ocean, the oceanic heat content (and hence thermal expansion) will continue to rise in the ocean for centuries to millennia, even when surface warming has halted. Haline contraction -or 55 expansion of ocean water due to freshening -is a smaller, though not negligible component of steric sea-level rise. Physicallybased models have been used to study the different components contributing to g...

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“…In an ill-conditioned problem, the sensitivity at the surface to perturbations at the base is low. This matrix can also be used to quantify the uncertainty in the ice flow due to uncertainties in the model parameters (see, e.g., Bulthuis et al, 2019;Schlegel et al, 2018;Smith, 2014). Perturbations at the ice base with short wavelength are propagated to the surface with a weaker effect on the height and velocity compared to long wavelengths in Gudmundsson (2003Gudmundsson ( , 2008.…”

Section: G Cheng and P Lötstedt: Sensitivity Analysis Of Ice Sheetmentioning

confidence: 99%

“…The FS equations are solved using Elmer/Ice version 8.4 (rev. f6bfdc9) with the scripts at: https://doi.org/10.5281/zenodo.3611158 (Cheng, 2020a). The forward and adjoint SSA solvers are implemented in MATLAB.…”

Section: A1 the Forward Steady-state Ssa Solutionmentioning

confidence: 99%

Parameter sensitivity analysis of dynamic ice sheet models – numerical computations

Cheng

Lötstedt

2020

The Cryosphere

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Abstract. The friction coefficient and the base topography of a stationary and a dynamic ice sheet are perturbed in two models for the ice: the full Stokes equations and the shallow shelf approximation. The sensitivity to the perturbations of the velocity and the height at the surface is quantified by solving the adjoint equations of the stress and the height equations providing weights for the perturbed data. The adjoint equations are solved numerically and the sensitivity is computed in several examples in two dimensions. A transfer matrix couples the perturbations at the base with the perturbations at the top. Comparisons are made with analytical solutions to simplified problems. The sensitivity to perturbations depends on their wavelengths and the distance to the grounding line. A perturbation in the topography has a direct effect at the ice surface above it, while a change in the friction coefficient is less visible there.

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Uncertainty quantification of the multi-centennial response of the Antarctic ice sheet to climate change

Cited by 89 publications

References 115 publications

ESD Reviews: mechanisms, evidence, and impacts of climate tipping elements

ESD Reviews: mechanisms, evidence, and impacts of climate tipping elements

Semi-equilibrated global sea-level change projections for the next 10 000 years

Parameter sensitivity analysis of dynamic ice sheet models – numerical computations

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