|The Week That Was
November 20, 1999 NEW ON THE SEPP WEB:
Sea-level rise is probably the most-feared consequence of a putative global warming. But --- surprise, surprise -- the science now says otherwise. SL will continue to rise for many thousands of years more, no matter what we do! But greenhouse warming may slow it down somewhat. You may agree after you read our essay; but how to convince the politicians?
If you have read the essay on New on the SEPP Web, you already know the answer: Real but not man-made. Relax and listen to scare stories:
From Dan Rather on CBS NEWS Monday, November 1,1999: Smith Island Is Drowning:
As the New Year approaches, CBS News is looking ahead to what you can expect in the 21st century. Ten miles and a world away from Maryland's eastern shore lies a tiny, forgotten piece of America, an old jewel poking out of the Chesapeake. But its days are numbered, because slowly but surely, Smith Island is drowning.
The problem with Smith Island is that the water around it is rising. And to make matters worse, the land is sinking. A strong high tide can easily swamp the island, which sits a mere two feet above sea level.
Smith Island may seem an unimportant relic of the past but in fact, it offers a disturbing glimpse into the next millennium.
"Smith Island's a look ahead, it's a precursor of what we expect to happen to other islands in the future, to other low lying islands," says coastal scientist Stephen Leatherman. Leatherman says the rising sea level that's engulfing the island is a direct result of global warming. "We expect the possibility of as much sea level rise as three feet over the next century," says Jerry Mahlman of the National Oceanic & Atmospheric Administration.
The damage, according to some models, could be catastrophic:
whole sections of South Florida, North Carolina's Outer Banks, New Jersey's
barrier islands, and even New Orleans, will be under water. "This
problem is a candidate to be the defining problem of the 21st century.
In my view the only thing that would make it not a leading candidate would
be World War III," says Mahlman. Sea level rise is just the
beginning: Fueled by larger, warmer seas, scientists predict hurricanes
will become more intense.
There's more: Floods like the one that devastated Grand Forks, North
Dakota, two years ago will be more common. There'll be more heat waves,
like the 1995 Chicago scorcher that took 700 lives. "Philadelphia
would be more like New Orleans," says Mahlman. "Where New Orleans
would become like I don't know what," he added.
And now from a book review of Michael Grubb's "The Kyoto Protocol --- a Guide and an Assessment'' by British enviro Aubrey Meyers, for whom Kyoto is not enough:
"Although global climate change raises dreadful problems that the
Kyoto Protocol does little to address, Michael Grubb's book hails it as
a "remarkable achievement". This should be taken with a pinch
of salt. If you asked people from the Maldives what they felt about the
Protocol, they'd probably say, frightened about their lack of a future.
They know that accumulating greenhouse gas emissions warm the planet and
expand the oceans and obliterate them, and God knows whom and what else.
Their fears have a message for us all: - this problem is global and needs
a global solution. "Equity and survival" sums it up. Everyone
has to be in as no one is saved until everyone is saved.
Surprise theory behind big Antarctic thaw: Global warming isn't to blame. Ice field will shrink regardless, threatening coasts.
Amid increasing evidence of global warming, scientists have pointed to
thawing polar icecaps in Antarctica and rising sea levels that threaten
to flood low-lying islands the
But new evidence from Antarctica published today in the journal Science indicates the thawing of at least one major ice field is a natural event that has little to do with global warming.
Aside from challenging accepted theories behind global warming, these findings illustrate the complexities that go along with predicting how the earth will react to high levels of fuel consumption and deforestation, supposedly the two main causes of global warming.
At issue is the West Antarctic Ice Sheet. This frozen wasteland measures 360,000 square miles, an area larger than Texas and Colorado combined. The WAIS is one of the largest ice sheets on the planet, and for that reason, it could have an enormous effect on sea levels worldwide.
Unlike any other ice sheet, the WAIS is anchored to land below sea level what's known as a marine ice sheet. Because of its ocean exposure and position on the sea floor, scientists say it is potentially unstable and could be more affected by changes in sea level or ocean temperature than other ice fields.
Sure enough, the WAIS is changing faster than any other ice sheet. It has shrunk at a rate of about 400 feet per year during the past 7,600 years, according to the scientists.
All told, the WAIS has receded about 800 miles since the height of the last ice age, 10,000 years ago. According to the researchers' calculations, the Western Antarctic ice shield could completely collapse in the next 7,000 years.
But the thawing of the WAIS long predates the period when mankind began to change the chemistry of the atmosphere through fossil-fuel burning and deforestation. In fact, during most of the period of the ice sheet's thaw, global temperatures were relatively stable. Furthermore, the pace at which the WAIS is thawing has not appreciably sped up during the recent decades when global warming has really begun to show up. This implies that global warming, at least so far, has little to do with the shrinking of the WAIS.
"What we are suggesting is that the ice sheet may continue to retreat regardless of any global warming or future rise in sea level." "Certainly warming up the oceans or expansion of the ocean could help the ice sheet retreat more quickly," says Howard Conway, a University of Washington geophysicist and lead author of the Science article.
But Dr. Conway also admits that the thawing will probably continue regardless of whether mankind gets their global warming affairs in order. Alternatively, global warming could also make the ice fields grow.
"With continued warming there might be increased precipitation down
there which would feed the ice sheet as well," says Conway, alluding
to the scenarios that could all plausibly play out as a result of global
But the future of the West Antarctic Ice Sheet "may have been predetermined when the grounding line retreat was triggered in early Holocene time," which was about 10,000 years ago, according to a team of scientists that was led by Dr. Howard Conway of the University of Washington in Seattle. They reported their findings on Friday [Oct. 8] in the journal Science.
The grounding line is the boundary between floating ice and ice thick enough to reach the sea floor, and the scientists found that line has receded about 800 miles since the last ice age, withdrawing at an average of about 400 feet per year for the last 7,600 years.
Referring to the melting, Dr. Conway said, "It seems like the rate that been going on since the early Holocene is similar to the rate right now." Dr. Conway said.
"Collapse appears to be part of an ongoing natural cycle, probably caused by rising sea level initiated by the melting of the Northern Hemisphere ice sheets at the end of the last ice age." Dr. Conway added in a telephone interview.
Continued shrinking of the ice sheet, perhaps even complete disintegration, "could well be inevitable," the report concluded.
According to estimates, the ice sheet's complete melting could raise
the global sea level by 15 to 20 feet, swamping low-lying coastal communities
worldwide. But, at the current rate of melting, that would take
about 7,000 years, the researchers estimated.