Will Antarctica Disappear? Ice Sheet Timeline & Climate Scenarios
Antarctica won't "disappear"—its bedrock continent is permanent. But its ice sheet (26.5M km³, 58 m sea-level equivalent) could substantially melt over centuries to millennia.
Current State
- Ice volume: 26.5 million km³ (90% of world's ice)
- Average thickness: 2.16 km; max 4.8 km (Astrolabe Basin)
- Mass balance: Losing ~150 Gt/yr (2012–2023 avg); accelerating from ~40 Gt/yr (1990s)
- Contribution to SLR: ~0.4 mm/yr currently
Melting Timelines by Scenario (IPCC AR6 / ISMIP6)
| Scenario | 2100 SLR from Antarctica | Long-Term (500–1000 yr) | Complete Loss? |
|---|
| SSP1-1.9 (1.5°C) | 0.04–0.12 m | ~1–2 m | No (mostly stable) |
| SSP2-4.5 (~2.7°C) | 0.1–0.25 m | ~3–5 m | No (WAIS collapse possible) |
| SSP5-8.5 (>4°C) | 0.2–0.4 m (up to 1 m w/ MICI*) | ~10–20+ m | Eventually (millennia) |
*MICI = Marine Ice Cliff Instability (high uncertainty)
Key Thresholds
- West Antarctic Ice Sheet (WAIS): Grounded below sea level; vulnerable to warm ocean intrusion. Potential irreversible collapse at ~1.5–2°C global warming → 3–5 m SLR over centuries.
- Wilkes & Aurora Basins (East Antarctica): Larger but more stable; require >3–4°C for major retreat.
- Surface melt: Currently limited; increases exponentially with warming.
What "Gone" Would Mean
- 58 m sea-level rise → every coastal city submerged
- Isostatic rebound: Continent rises ~500 m over millennia
- Climate feedback: Albedo loss → accelerated warming; circulation changes
Uncertainties
- Ice shelf buttressing dynamics
- Subglacial hydrology & geothermal heat
- MICI plausibility
- Future emissions trajectory (policy-dependent)
Bottom line: Total loss = thousands of years even in worst case. But multi-meter commitment is likely locked in for WAIS. Decisions this century determine the rate and ultimate extent.
Wanderlust World