Category: Sea Level Rise

Sea Level Rise

Photo by Mink Mingle on Unsplash
  • February 2019:  91 (+/- 4mm)  (Data since January 1, 1993)
  • Current Rate of Change:  +3.3 mm/year
    • 20th century average:  1.7 mm/year
  • Sources of sea level rise in the last decade
    • Endorheic global decline
    • 65%-85% due to thermal expansion (~1.1-1.4mm/yr)
    • Greenland, Antarctica ice sheet mass loss (~1.1-1.3mm/yr)
    • ~20-35% from other sources including mountain glacier and ice-cap loss, groundwater depletion, reservoir impoundment, and mass changes in other stores; e.g., lakes, soil, permafrost
    • the cumulative global groundwater depletion from 1900–2008 totaled ∼4,500 km3 from 1900–2008, equivalent to a sea‐level rise of 12.6 mm. As an identifiable, separate, semi‐independent hydrologic process, the volume and rate of estimated long‐term global groundwater depletion balances 6 to 7 percent of the observed SLR since 1900. (Konikow LF (2011) Contribution of global groundwater depletion since 1900 to sea-level rise. Geophys Res Lett 38(17), L17401. doi: 10.1029/2011gl048604)

Sea level rise is due to thermal expansion of seawater as it accumulates heat (see         above) and additional water from melting ice sheets and glaciers.

  Observed sea level since the start of the satellite altimeter record in 1993 (black line), plus independent estimates of the different contributions to sea level rise: thermal expansion (red) and added water, mostly due to glacier melt (blue). Added together (purple line), these separate estimates match the observed sea level very well. NOAA graphic, adapted from Figure 3.15a in State of the Climate in 2017.

Sea Level Tracked By Satellite Data 1993-Present

Source:  NASA Sea Level

Sea Level Derived From Coastal Tide Gauge Data 1870-2000

Source:  NASA Sea Level