BOX E.1
Parameters for Added Rapid Dynamic Response

Added dynamics (additional discharge assigned to each land ice source for simulation of increased rapid dynamic contribution)

•  Glaciers and ice caps: 50 percent of 324.8 GT yr-1 = 162.4 GT yr-1

•  Greenland Ice Sheet: Increase outlet glacier speed by 2 km yr-1 = 375.1 GT yr-1

•  Antarctic Ice Sheet: Double outlet glacier discharge to 264 GT yr-1

Variations (perturbations to base values selected for discharge used in the sensitivity calculation)

•  Glaciers and ice caps: Use 30 percent and 70 percent of 324.8 GT yr-1

•  Greenland Ice Sheet: Use 80 percent and 120 percent of 375.1 GT yr-1

•  Antarctic Ice Sheet: Use 80 percent and 120 percent of 264 GT yr-1

TABLE E.1 Range of Added Rapid Dynamic Response (cm) for the Cryosphere Components of Sea-Level Rise

Term 2030 2050 2100
Glaciers and ice caps 0–0.5 0–1.4 0–3.7
Greenland 0–1.2 0–3.3 0–8.4
Antarctica 0–0.8 0–2.3 0–5.9
Total cryosphere 0–2.5 0–7.0 0–18.0

 

TABLE E.2 Effect of Rapid Dynamic Response and Uncertainty on Future Cumulative Sea-Level Rise

2030 2050 2100
Base values: Projected sea-level rise Z with uncertainty δZ (cm)
Z
Z - δ Z
Z + δ Z
6.6
5.9
7.3
17.7
14.1
19.0
57.0
44.2
69.6
Projected sea-level rise with added dynamics Zd (cm)
Zd
Z + Zd
Z - δ Z + Zd
Z + δ Z + Zd
2.5
9.1
8.4
9.8
7.0
24.7
21.1
26.0
18.0
75.0
62.2
87.6
Percentage effect of added dynamics
Z + Zd
Z - δ Z + Zd
Z + δ Z + Zd
38%
42%
34%
40%
50%
37%
32%
41%
26%

 

Sensitivity of the Added Dynamics Analysis

The choice of fluxes for added rapid dynamic response (Box E.1) was guided by the analogy to the doubling of the Greenland mass balance deficit in 2000–2006 but was otherwise rather arbitrary. To investigate how sensitive this calculation is to the choice of added discharge flux, the input variables (discharge from glaciers and ice caps, Greenland, and Antarctica) were varied by ± 20 percent individually (no two inputs were varied at the same time), and the calculation was repeated to determine the response in the output (additional sea-level rise). The result of this sensitivity test is summarized in Table E.3. For variations of 20 percent magnitude in the inputs, output magnitudes varied by no more than 7 percent.



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