Sea level rise
According to Dave Aubrey, director of the Coastal Research Center, Woods Hole
Oceanographic Institute in Massachusetts, there is no trend in sea level rise that
is measurable. He points out the uncertainty in the data. Land moves up and down,
he says. He feels that there is no evidence of sea level rise due to global warming.
Team C005858 lives in the Chesapeake Bay watershed in the United States. It is a shallow
waterway that has experienced sea level rise (13.8 inches over the last 100 years), which is double the global rate in
the past 100 years. The problem has been the loss of wetlands, which serve as
spawning grounds and help to reduce algal growth, which blocks sunlight to the water's
bottom.
EPA's study using the Wigley & Raper model
The complexity is modeling comes from the fact that water can absorb almost endless amounts
of carbon dioxide. This "sink" phenomenon masks the real effects of increasing CO2.
With global warming, two things happen: thermal expansion, where waters expand like a heated
gas and melting of ice, which releases floating frozen water into the ocean.
By clicking on the reference for this study below, one can see the complexity in building
these models, especially in the discussion in chapter 2. Because of the sink phenomenon,
the calculations are logarithmic rather than geometric. Rather than using algebra,
calculus is more appropriate in modeling the differentials in the interaction of the
sinks and feedbacks.
Another complexity pointed out in the report is the fact pointed out by Manabe that the
oceans warm at 1/2 the land rate. Deep water remains cooler than surface water. Shallow
waters don't retain or absorb heat as readily. The group at the end felt less confident
about the increase in global temperature due to ensuing discussions.
In this study, all but one scientist (Robert Balling of ASU) was involved with IPCC
promulgations in its literature. Thus, all concluded (but Balling) that there was a 90% confidence
that with carbon dioxide's doubling, surface temperature would increase in the model
for circulation by 2.7°F to 8.1°F. Balling was upset that the modeling did not
allow for the possibility of cooling effects. As we have seen in earlier tabs of the
policy section, Balling represents warming skeptics.
On page 24 of chapter 3 of this study, David Rind noted the limitations of using a
one-dimensional (opposed to a three-dimensional) model for showing the additional warming
due to spatial distribution. The reason for using the one-dimensional simplicity of
the Wigley and Raper model was "limitation of funding."
On page 26 of chapter 3 of the study MacCracken and Manabe point out that with global warming,
precipitation might lead to lower sea levels.
The overall conclusion, globally, is that sea level is rising .08 inches a year.
Greenland ice sheets
Now we're talking about some major ice! It runs 1,579 miles North to South,
80 miles in width, and 5,000 feet deep. It is 20% of the world's ice and if
melted would add 20 feet to sea level.
Chapter 4 points out that in looking at Greenland, runoff from precipitation affects
sea levels, because as warming increases, precipitation becomes rain (runoff) rather than
snow (retained ice).
NASA reports massive glacier thinnings in southern Greenland. NASA is going to
study the Canadian glaciers, which are of lower elevation than Greenland's. NASA attributes
Greenland's glacier thinning to climate change.
The overall conclusion reached in chapter 5 of the study on page 114 was that between
now and 2050, the year of carbon dioxide doubling (since the industrial revolution),
the Antarctic contribution to sea level rise would be negligible. However, after
2100, its impact would be significant.
The less-dense freshwater release could reduce the cold water that sinks down to the deep,
because of the salinity difference.
Other world glaciers
Scientific American notes that world glaciers have gone for 150 to 50 since 1850 due
to global warming. The article notes that the largest glacier on Mount
Kenya has decreased 92%. They predict that glaciers in Glacier National Park in Montana
will totally disappear in 50 years. The glaciers on the Caucasus Mountains
had decreased 50% in the last 100 years in Russia.
REF: Hall, Alan; Going, Going -- Gone? Much of the world's water is stored in
glaciers and the great polar ice sheets. But these frozen reservoirs are melting rapidly,
and the water they release could cause a catastrophic rise in sea levels;
Scientific American; April 26, 1999.
http://www.sciam.com/explorations/1999/042699meltdown/index.html
Sea level rise measurement complication
Scientific American points out that land rise has made it seem like sea level has been
decreasing in some areas where in fact the sea level has been rising. The article points
to examples of this in Scandinavia.
Arctic ice meltdown
Walter Gibbs reported in an article called "Research predicts summer doom for
northern icecap in the July 11, 2000 edition of the New York Times, that
Norwegian scientists predict that the Arctic will be ice-free in 50 years.
Tore Furevik is quoted in commenting on the trend in meltdown. This would open
shipping between Germany and Japan, saving some 4,800 miles of shipping channel.
While scientists find global warming to be a part, most is due to shifting winds.
REF: Gibbs, Walter; Research predicts summer doom of northern icecap;
New York Times; July 11, 2000.
Anthropogenic connection to Arctic meltdown
Scientists form the University of Maryland, Rutgers, the University of Illinois, and
the Hadley Center working with NOAA and NASA, in examining satellite data showing Arctic
ice meltdowns the size of Maryland and Delaware since 1978, feel like the cause is
anthropogenic.
Dangerous feedbacks - Greenland lab
The National Science Foundation supports a lab of 24 scientists studying in
Greenland. There is no fear at this time, in spite of temperatures rising 18°F
in the 1990s, because the temperatures still are below freezing. However, with warming
air and more precipitation, comes more snow.
These scientists have found that the snow acts as a catalyst in destroying the ozone
layer.
Also, they have found that the snow (which is increasing in frequency because of the
warmer air, due to global warming) reacts with the nitrogen and oxygen putting
off nitrous oxide, a powerful greenhouse gas.
Lastly, as noted elsewhere, water (vs. ice) acts to absorb carbon dioxide. But,
ice reflects solar energy. When it melts, warming occurs faster. This is a positive
feedback.
REF: Suplee, Curt; For 500 million, a sleeper on Greenland's Ice Sheet;
Washington Post, Page A09; Monday, July 10, 2000.
