Sea Level Rise
Global sea levels have risen significantly since 1880, with the rate of rise accelerating in recent decades due to melting ice and thermal expansion.
Key Statistics
Total Sea Level Rise Since 1880
0 cm
Global mean sea level has risen 8–9 inches (21–24 centimeters) since 1880.
Current Rate of Rise
0.0 mm/year
The rate has more than doubled from 1.4 mm per year throughout most of the twentieth century to 3.6 mm per year from 2006–2015.
Projected Rise by 2100
0+ cm
Even on the pathway with the lowest possible greenhouse gas emissions, global mean sea level would rise at least 30 cm above 2000 levels by 2100.
Global Sea Level Trends
Data source: NOAA Climate. Sea level measurements from tide gauges (1880-1993) and satellite altimetry (1993-present).
Sea Level Rise Impacts
Sea level rise is already causing more frequent and severe coastal flooding in many locations around the world, threatening infrastructure, ecosystems, and communities.
Causes and Impacts
Primary Causes
- Thermal Expansion: As ocean water warms, it expands, taking up more space and causing sea levels to rise.
- Melting Ice Sheets: The Greenland and Antarctic ice sheets are losing billions of tons of ice annually, adding water to the oceans.
- Glacier Melt: Mountain glaciers worldwide are retreating, contributing additional water to the oceans.
Key Impacts
- Coastal Flooding: Higher background water levels mean that deadly and destructive storm surges push farther inland than they once did.
- Infrastructure Damage: Roads, bridges, subways, water supplies, oil and gas wells, power plants, sewage treatment plants, and landfills are all at risk.
- Ecosystem Disruption: Rising sea levels create stress on coastal ecosystems that provide recreation, protection from storms, and habitat for fish and wildlife.
- Saltwater Intrusion: Contamination of freshwater aquifers that sustain municipal and agricultural water supplies.
Future Projections
Sea levels will continue to rise for centuries due to the warming that has already occurred. The rate and amount of rise depend on future emissions and how quickly ice sheets respond to warming.
Low Emissions Scenario
0.3-0.6 meters by 2100
Requires immediate, dramatic emissions reductions
Medium Emissions Scenario
0.5-1.0 meters by 2100
Based on current policies and pledges
High Emissions Scenario
1.0-2.2 meters by 2100
With rapid ice sheet collapse, potentially 3.9 meters by 2150
Regional Variations
Sea level rise is not uniform across the globe. Some regions experience faster rise than others due to ocean currents, land subsidence, and other local factors.
Regions with Accelerated Sea Level Rise:
- U.S. East Coast: Experiencing rates 3-4 times the global average in some areas due to land subsidence and changes in ocean currents.
- Western Pacific: Some islands have seen rates of rise 3 times the global average.
- Southeast Asia: Particularly vulnerable due to low-lying deltas and high population density.
