[ExI] Sea level rise (was: Curves on a graph (was Re:RichardLindzen on climatehysteria))

BillK pharos at gmail.com
Thu Aug 6 19:07:16 UTC 2009

On 8/6/09, Tomaz Kristan wrote:
> What superriver fils the Ocean, Alfio?


Global sea level is currently rising as a result of both ocean thermal
expansion and glacier melt, with each accounting for about half of the
observed sea level rise, and each caused by recent increases in global
mean temperature. For the period 1961-2003, the observed sea level
rise due to thermal expansion was 0.42 millimeters per year and 0.69
millimeters per year due to total glacier melt (small glaciers, ice
caps, ice sheets) (IPCC 2007). Between 1993 and 2003, the contribution
to sea level rise increased for both sources to 1.60 millimeters per
year and 1.19 millimeters per year respectively (IPCC 2007).

Antarctica and Greenland, the world's largest ice sheets, make up the
vast majority of the Earth's ice. If these ice sheets melted entirely,
sea level would rise by more than 70 meters. However, current
estimates indicate that mass balance for the Antarctic ice sheet is in
approximate equilibrium and may represent only about 10 percent of the
current contribution to sea level rise coming from glaciers. However,
some localized areas of the Antarctic have recently shown significant
negative balance, e.g., Pine Island and Thwaites Glaciers, and
glaciers on the Antarctic Peninsula. There is still much uncertainty
about accumulation rates in Antarctica, especially on the East
Antarctic Plateau. The Greenland Ice Sheet may be contributing about
30 percent of all glacier melt to rising sea level. Furthermore,
recent observations show evidence for increased ice flow rates in some
regions of the Greenland Ice Sheet, suggesting that ice dynamics may
be a key factor in the response of coastal glaciers and ice sheets to
climate change and their role in sea level rise.

In contrast to the polar regions, the network of lower latitude small
glaciers and ice caps, although making up only about four percent of
the total land ice area or about 760,000 square kilometers, may have
provided as much as 60 percent of the total glacier contribution to
sea level change since 1990s (Meier et al., 2007).


More information about the extropy-chat mailing list