Sea Level Rise Bickering
The UN's Intergovernmental Panel on Climate Change (IPCC) is set to release its Fifth Assessment Report (AR5) of the physical science of climate change at the conclusion of its meeting in Stockholm, September 23-26th.
Although the assessment has yet to be released, leaked documents are already being shredded by climate deniers.
A leaked document of the IPCC Sea Level Rise(SLR) Assessment is among them. In an article published by the Cato Institute, the authors not only deride the panel's findings but claim that the rates of sea levels rise are not increasing, but in fact slowing and that scientific research has shown that Pacific Decadal Oscillation and groundwater depletion are the main causes of sea level fluctuations.
Our own report on Sea level Rise which featured scientists form the USGS, NASA/ESA and NRCan, reveals that there is
strong evidence that global sea level is now rising at an increased rate and that it most likely will continue to rise during this century.
With a view to further clarifying the causes of Sea Level Rise we sent the following questions to Virginia Burkett, Chief Scinetist for Global Change, USGS.
There are different types of ice in the Arctic and antarctic: glaciers, icebergs, ice sheets and land ice? Do they all contribute to Sea Level Rise (SLR)?
Yes the "wasting" or melting of land ice that ultimately drains to the ocean contributes to mean sea level. The other major driver of sea level rise is thermal expansion -- when water is heated it expands. (Icebergs should not be included in your list because they are already in the ocean and their volume is already contributing to ocean mass and sea level.)
Land ice has been melting for millions of years, why is this and does it play a role in SLR?
Actually land Ice has not been melting for millions of years, but numerous glacial "cycles" have been recorded in the Earth's sediments and ice sheets for millions of years. Most scientists attribute these natural glacial cycles to orbital forcing. The last Glacial Maximum was about 21,000 years ago; since then global sea level has risen about 120 meters. Sea level rose rapidly (averaging almost 0.9 m per century) between 20,000 and 6,000 years before present and then it slowed to about 0.2 m per century or less during the past 3,000 years. From the mid-19th century through the 20th century the average rate of global sea level rise increased to between 0.17 and 0.18 m per century, and satellite data for the last 15 years suggests that the contemporary rate is as much as 0.3 m per century, or roughly doubled the 20th century rate.
Related Water Chronicles Stories
SEA LEVEL RISE & CRISIS MANAGEMENT - Q&A Virginia Burkett, Chief Scientist, Climate & Land Use Change, USGS.- 12/14/12
GREENLAND ICE SHEETS LOSING MASS FASTER & FASTER - NASA/ESA - Q&A Glenn Milne, Geophysicist, Ottawa University - 1/4/13
PARTS OF CANADIAN ARCTIC MAY BE SPARED - Q&A Thomas James, Geological Survey of Canada - 1/16/13
CANADA A LEADER IN CLIMATE CHANGE ADAPTATION - Q&A- Don Lemmen NRCAn Lead Scientific Editor Adaptation Report - 2/5/13
GROUNDWATER DEPLETION AND SEA LEVEL RISE- Q&A- Leonard Konikow, USGS - 5/23/13
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