MODERN TIMES
by Art Hobson
ahobson@uark.edu
ICE SHEETS, KYOTO, AND GLOBAL WARMING
A
lot has happened on the global warming front since my last report on 20 March
(http://physics.uark.edu/hobson/ ).
The
list of possible disasters has just become more dangerous. That list includes shutting off the
oceanic "pump" that keeps the Gulfstream and other global ocean
currents circulating; a sudden release of deposits of methane--a potent global
warming gas--from the ocean floor; melting of the entire Arctic ice cap within
a few decades; and breakup of the mile-thick West Antarctic Ice Sheet. There are recent reports that this last
disaster, the breakup of the WAIS, may be already beginning.
Although
it would take thousands of years for global warming to directly melt the entire
WAIS, there are subtle ways to destabilize it. This huge ice sheet has always slid slowly downhill toward
the sea, with a rough balance between the amount of ice disappearing into the
water each year and the amount added from snowfall. Since 1990, parts of the WAIS have begun sliding much
faster, carrying two or three times as much ice into the sea as is replaced by
snowfall. Glacier specialists
aren't sure why this is happening, but they believe that warmer ocean waters
are eating away at the underside of the large ice shelf where it is first
"grounded" on the land, and this loosens the ocean end of the WAIS,
causing it to slip toward the sea.
As the ocean-end slides downhill, it appears to drag the entire
WAIS--three times the size of Texas--along with it.
The
WAIS actually comprises six separate glaciers, and only one of the smaller ones
is increasing its seaward flow.
But because they don't entirely understand the process, experts can't
say whether the WAIS's two largest ice shelves--each of them the size of
Texas--could also begin sliding downhill.
The entire WAIS could gradually slide into the sea during the next few
centuries, raising global sea levels by a disastrous 16 feet, or a few feet
every century. This sliding process,
once it has gotten very far along, could be impossible to stop. A rise of a few feet in the next 100
years would be disastrous. Sea
levels have risen by 4 to 10 inches during the past century, and coastal
nations such as Bangladesh are already feeling the pain.
On
the positive side, and little-noted by our environmentally-negligent press,
Russian President Vladimir Putin has approved the Kyoto treaty on climate
change and it will soon be ratified by the Russian parliament. The treaty, drawn up in 1997 at an
international meeting in Kyoto, Japan, sets limits for emissions of the gases
that cause global warming.
However, the treaty will not actually be legally binding until it has
been ratified by nations representing 55 percent of the world's industrial
carbon emissions. Once it becomes
legally binding, the treaty will require the ratifying nations to obey the
limits set by the treaty. Although
124 nations have ratified the treaty, the USA is not among them. Ever since 2001, when President Bush reversed
President Clinton's pro-Kyoto stance and rejected the treaty, the USA has been
the main holdout nation preventing the treaty from entering into force. Because the USA alone emits over 25
percent of the world's total, it's been hard achieve the 55 percent
figure. Ratification by Russia,
which accounts for 17 percent of global emissions, will put the ratifying
nations above 55 percent and bring the treaty into force.
A
lot will change once the treaty is in force. Signatory industrialized nations must then reduce their
emissions by 5 percent below 1990 levels, by 2012. To achieve this at the least possible cost, these nations
will establish a "carbon trading system" under which they will
receive "carbon emission permits" allowing each nation to emit a
prescribed amount of carbon each year.
The permits will be tradeable:
Nations having more permits than they need can sell them to other
nations, putting an economic premium on reducing carbon emissions. The USA will be left out of the
commerce engendered by this trading system. We will fall increasingly behind the world in constraining
carbon emissions, and carbon-emitting US goods will be shunned by the rest of
the world.
This
is happening as the scientific establishment expresses concern about the Bush
administration subjecting scientific issues such as global warming to political
tests. After a four-year history
of rejecting the science of climate change, our president has grudgingly
accepted the reality of global warming.
However he has refused to recommend any remedy stronger than voluntary
business measures, and research toward a distant hydrogen economy. If the president is seriously
interested in action on global warming and energy issues, solutions are close
at hand. A 50-cent gasoline tax,
with the proceeds perhaps distributed back as income tax relief, would reduce
foreign oil imports, would ultimately save money for consumers, and would
reduce carbon emissions. Raising
gasoline efficiency standards to a realistic and achievable 40 mpg would
accomplish much more than Bush's tenuous hydrogen initiative.
It's depressing that the press and the presidential candidates have been so negligent about environmental matters in general and global warming in particular. Let's hope that we don't need a real disaster, such as the WAIS sliding into the sea, to wake us up. Besides being our wake-up call, it could be civilization's death knell.