Coal should be global warming concern - Scientists
Researchers and officials concerned about global warming have focused
on oil usage, but scientists said liquefied coal could have a greater
affect on global climate change.
Global warming scenarios are based on oil reserves, but those
reserves will have less impact on global climate than the extent to
which liquefied coal replaces oil and gas, scientists said at a meeting
of the American Geophysical Union in San Francisco.
"Oil and gas by themselves don't have enough carbon to keep us in the
dangerous zone for very long by themselves, but that's assuming we do
something about coal," Pushker Kharecha, a researcher for the U.S. space
agency NASA and Columbia University in New York.
Estimates vary, but coal is the most abundant fossil fuel, and
countries like China and the United States are looking at liquefaction
technology. Many industries in South Africa already use liquefied coal.
In 2007, Illinois Democratic Sen. Barack Obama and Kentucky
Republican Jim Bunning introduced legislation that would set the stage
for large-scale production of transportation fuels from coal.
President-elect Obama come from state with prodigious coal supplies.
Liquefied coal releases 40 per cent more carbon dioxide than oil when
burned, said Ken Caldeira, a scientist at the Carnegie Institution of
Washington. "Addressing the climate problem means addressing the coal
problem," he said. "Whether there's a little more oil or a little less
oil will change the details, but if we want to change the overall shape
of the warming curve, it matters what we do with coal."
Caldeira said his climate models show that if all oil used in the
world is replaced with liquefied coal, global temperatures will rise 2
degrees Celsius (3.6 degrees Fahrenheit) by 2042, three years sooner
than if oil remains a staple.
If oil is replaced with solar, wind, or nuclear power, temperatures
will rise 11 years later. Many scientists believe high levels of
atmospheric carbon dioxide lead to warming and effects like melting
glaciers, thawing permafrost, ocean acidification and latitudinal shifts
in climate.
Current atmospheric carbon dioxide levels are 385 parts per million
and rising at a rate of about 2 parts per million (ppm) year as a result
of burning coal, oil, and gas, the researchers said.
The generally accepted threshold for atmospheric carbon dioxide is
450 ppm. But scientists today said that number should be 350 ppm.
Climate change is a slow process, Kharecha said, and the effects may
take decades and centuries to show up.
"There are currently more than enough fossil fuels and coal to push
us well past safe atmospheric CO2 levels," he said. None of the models
presented at the session included carbon dioxide emissions from
unconventional fossil fuels like tar sands, methane hydrates or oil
shale.
Representatives from the liquefied coal industry could not be
immediately reached for comment. In February, Robert Kelly of DKRW
Advanced Fuels, which is building a liquefied coal production facility
in Wyoming, told Reuters, "liquefied coal could be a huge fuel source
for the next 50 years if we do it responsibly." He said coal emissions
could be safely captured and stored underground. REUTERS |