Limits...
Combustion of available fossil fuel resources sufficient to eliminate the Antarctic Ice Sheet.

Winkelmann R, Levermann A, Ridgwell A, Caldeira K - Sci Adv (2015)

Bottom Line: With cumulative fossil fuel emissions of 10,000 gigatonnes of carbon (GtC), Antarctica is projected to become almost ice-free with an average contribution to sea-level rise exceeding 3 m per century during the first millennium.Beyond this additional carbon release, the destabilization of ice basins in both West and East Antarctica results in a threshold increase in global sea level.Unabated carbon emissions thus threaten the Antarctic Ice Sheet in its entirety with associated sea-level rise that far exceeds that of all other possible sources.

View Article: PubMed Central - PubMed

Affiliation: Potsdam Institute for Climate Impact Research, 14412 Potsdam, Germany. ; Physics Institute, Potsdam University, 14476 Potsdam, Germany. ; Department of Global Ecology, Carnegie Institution for Science, Stanford, CA 94305, USA.

ABSTRACT
The Antarctic Ice Sheet stores water equivalent to 58 m in global sea-level rise. We show in simulations using the Parallel Ice Sheet Model that burning the currently attainable fossil fuel resources is sufficient to eliminate the ice sheet. With cumulative fossil fuel emissions of 10,000 gigatonnes of carbon (GtC), Antarctica is projected to become almost ice-free with an average contribution to sea-level rise exceeding 3 m per century during the first millennium. Consistent with recent observations and simulations, the West Antarctic Ice Sheet becomes unstable with 600 to 800 GtC of additional carbon emissions. Beyond this additional carbon release, the destabilization of ice basins in both West and East Antarctica results in a threshold increase in global sea level. Unabated carbon emissions thus threaten the Antarctic Ice Sheet in its entirety with associated sea-level rise that far exceeds that of all other possible sources.

No MeSH data available.


Related in: MedlinePlus

Sea-level commitment from Antarctic ice loss.Given is the total sea-level change after 1000 years (yellow), 3000 years (orange), and 10,000 years (red) after year 2000 for each of the scenarios depicted in Fig. 1. The maximum temperature anomaly and the temperature anomaly after 10,000 years are given on the upper x axis. If all of the currently attainable carbon resources [estimated to be between 8500 and 13.600 GtC (4)] were burned, the Antarctic Ice Sheet would lose most of its mass, raising global sea level by more than 50 m. For the 125 GtC as well as the 500, 800, 2500, and 5000 GtC scenarios, the ice-covered area is depicted in white (ice-free bedrock in brown). For more details, see fig. S5.
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Figure 2: Sea-level commitment from Antarctic ice loss.Given is the total sea-level change after 1000 years (yellow), 3000 years (orange), and 10,000 years (red) after year 2000 for each of the scenarios depicted in Fig. 1. The maximum temperature anomaly and the temperature anomaly after 10,000 years are given on the upper x axis. If all of the currently attainable carbon resources [estimated to be between 8500 and 13.600 GtC (4)] were burned, the Antarctic Ice Sheet would lose most of its mass, raising global sea level by more than 50 m. For the 125 GtC as well as the 500, 800, 2500, and 5000 GtC scenarios, the ice-covered area is depicted in white (ice-free bedrock in brown). For more details, see fig. S5.

Mentions: This qualitative difference vanishes when looking at the long-term evolution of the ice sheet. Over the entire 10,000 years of simulation, sea level keeps rising for all scenarios. This extends, by more than an order of magnitude, the IPCC’s statement that sea level will continue to rise for centuries to come (5). Figure 2 shows the ice loss in terms of global sea-level rise after 1000, 3000, and 10,000 years (see also fig. S5). Ice loss is mainly driven by two self-reinforcing feedbacks: the marine ice-sheet instability and the surface elevation feedback. In the former, ocean warming leads to enhanced sub-shelf melting and, subsequently, to a retreat of the grounding line, which separates the grounded ice sheet from the floating ice shelves. In our simulations, the basal melt sensitivity, that is, the increase of large-scale sub-shelf melting per degree of warming, is generally within the observed (24, 25) range of 7 to 16 m year−1 °C−1 (see fig. S3). When the sub-shelf melt rate is large enough to force the grounding line to retreat into an area where the ice is grounded below sea level on an inward-sloping bedrock (26), it can become unstable. Several regions in Antarctica are subject to this so-called marine ice-sheet instability (6): Recent observations show that the grounding line has probably already transgressed into the unstable regime in the Amundsen Basin of West Antarctica because of warm water intrusion into the shelf cavities (though this might potentially be unrelated to anthropogenic warming) (27). Consistent with these observations (27) and with simulations performed with other ice-sheet models (28, 29), in our simulations the West Antarctic Ice Sheet becomes unstable after cumulative carbon emissions reach 600 to 800 GtC.


Combustion of available fossil fuel resources sufficient to eliminate the Antarctic Ice Sheet.

Winkelmann R, Levermann A, Ridgwell A, Caldeira K - Sci Adv (2015)

Sea-level commitment from Antarctic ice loss.Given is the total sea-level change after 1000 years (yellow), 3000 years (orange), and 10,000 years (red) after year 2000 for each of the scenarios depicted in Fig. 1. The maximum temperature anomaly and the temperature anomaly after 10,000 years are given on the upper x axis. If all of the currently attainable carbon resources [estimated to be between 8500 and 13.600 GtC (4)] were burned, the Antarctic Ice Sheet would lose most of its mass, raising global sea level by more than 50 m. For the 125 GtC as well as the 500, 800, 2500, and 5000 GtC scenarios, the ice-covered area is depicted in white (ice-free bedrock in brown). For more details, see fig. S5.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643791&req=5

Figure 2: Sea-level commitment from Antarctic ice loss.Given is the total sea-level change after 1000 years (yellow), 3000 years (orange), and 10,000 years (red) after year 2000 for each of the scenarios depicted in Fig. 1. The maximum temperature anomaly and the temperature anomaly after 10,000 years are given on the upper x axis. If all of the currently attainable carbon resources [estimated to be between 8500 and 13.600 GtC (4)] were burned, the Antarctic Ice Sheet would lose most of its mass, raising global sea level by more than 50 m. For the 125 GtC as well as the 500, 800, 2500, and 5000 GtC scenarios, the ice-covered area is depicted in white (ice-free bedrock in brown). For more details, see fig. S5.
Mentions: This qualitative difference vanishes when looking at the long-term evolution of the ice sheet. Over the entire 10,000 years of simulation, sea level keeps rising for all scenarios. This extends, by more than an order of magnitude, the IPCC’s statement that sea level will continue to rise for centuries to come (5). Figure 2 shows the ice loss in terms of global sea-level rise after 1000, 3000, and 10,000 years (see also fig. S5). Ice loss is mainly driven by two self-reinforcing feedbacks: the marine ice-sheet instability and the surface elevation feedback. In the former, ocean warming leads to enhanced sub-shelf melting and, subsequently, to a retreat of the grounding line, which separates the grounded ice sheet from the floating ice shelves. In our simulations, the basal melt sensitivity, that is, the increase of large-scale sub-shelf melting per degree of warming, is generally within the observed (24, 25) range of 7 to 16 m year−1 °C−1 (see fig. S3). When the sub-shelf melt rate is large enough to force the grounding line to retreat into an area where the ice is grounded below sea level on an inward-sloping bedrock (26), it can become unstable. Several regions in Antarctica are subject to this so-called marine ice-sheet instability (6): Recent observations show that the grounding line has probably already transgressed into the unstable regime in the Amundsen Basin of West Antarctica because of warm water intrusion into the shelf cavities (though this might potentially be unrelated to anthropogenic warming) (27). Consistent with these observations (27) and with simulations performed with other ice-sheet models (28, 29), in our simulations the West Antarctic Ice Sheet becomes unstable after cumulative carbon emissions reach 600 to 800 GtC.

Bottom Line: With cumulative fossil fuel emissions of 10,000 gigatonnes of carbon (GtC), Antarctica is projected to become almost ice-free with an average contribution to sea-level rise exceeding 3 m per century during the first millennium.Beyond this additional carbon release, the destabilization of ice basins in both West and East Antarctica results in a threshold increase in global sea level.Unabated carbon emissions thus threaten the Antarctic Ice Sheet in its entirety with associated sea-level rise that far exceeds that of all other possible sources.

View Article: PubMed Central - PubMed

Affiliation: Potsdam Institute for Climate Impact Research, 14412 Potsdam, Germany. ; Physics Institute, Potsdam University, 14476 Potsdam, Germany. ; Department of Global Ecology, Carnegie Institution for Science, Stanford, CA 94305, USA.

ABSTRACT
The Antarctic Ice Sheet stores water equivalent to 58 m in global sea-level rise. We show in simulations using the Parallel Ice Sheet Model that burning the currently attainable fossil fuel resources is sufficient to eliminate the ice sheet. With cumulative fossil fuel emissions of 10,000 gigatonnes of carbon (GtC), Antarctica is projected to become almost ice-free with an average contribution to sea-level rise exceeding 3 m per century during the first millennium. Consistent with recent observations and simulations, the West Antarctic Ice Sheet becomes unstable with 600 to 800 GtC of additional carbon emissions. Beyond this additional carbon release, the destabilization of ice basins in both West and East Antarctica results in a threshold increase in global sea level. Unabated carbon emissions thus threaten the Antarctic Ice Sheet in its entirety with associated sea-level rise that far exceeds that of all other possible sources.

No MeSH data available.


Related in: MedlinePlus