8.1 Projections for the 21st Century

During the 21st century, sea level will continue to rise due to warming from both past (20th century and earlier) and 21st century greenhouse gas emissions. The most robust projections of 21st century sea-level rise are the Assessments of the Intergovernmental Panel on Climate Change (IPCC) of 2001 and 2007.

In its 2007 assessment of global warming, the Intergovernmental Panel on Climate Change (IPCC) projected that global mean sea level is expected to rise between 0.18 to 0.59 meters (0.6 and 2 feet) in the next century.

Figure 7 Sea Level Change (source: IPCC, 2007)

Estimates of the ocean thermal expansion are made with coupled climate models for the range of SRES greenhouse gas emission scenarios. Recent estimates indicate that non-polar glaciers and ice caps may contain only enough water to raise sea level by 15 to 37 centimetres (Lemke et al. 2007). The largest contribution is from large glaciers in regions with heavy precipitation, such as the coastal mountains around the Gulf of Alaska, or Patagonia and Tierra del Fuego in South America. Many of these glaciers flow into the sea or large lakes and melt quickly because the ice is close to melting temperature.