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Scientists conclude global warming is unequivocal
By Mark Rainer
10 February 2007
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The Intergovernmental Panel on Climate Change (IPCC) released
the Summary for Policy Makers from its fourth assessment
report on science of global warming and climate change February
2. The new report concludes that global warming is unequivocal
and strengthens the previous assessment that most warming in the
last 50 years is due to human activity.
The IPCC report predicts a greater frequency of heat waves,
more intense tropical cyclones (typhoons and hurricanes), the
possible disappearance of summer Arctic sea ice, increasing acidification
of the ocean, and changing patterns of precipitation that will
cause an increasing number of draughts for some portions of the
world. Depending on the scenario, global temperatures will rise
between 1.8 and 4 degrees Celsius and sea levels will rise between
18 and 59 centimeters before the next century.
Established in 1988 by World Meteorological Organization and
United Nation Environmental Programme, the IPCC assesses scientific,
technical and socioeconomic information relevant to the understanding
of climate change. The IPCCs reportthe most comprehensive
of its kindis an assessment of the current scientific research
on climate change and global warming. It draws upon the work of
2,500 scientists from 130 countries and represents a broad consensus
within the scientific community. All scientific findings considered
by the IPCC and thus forming the basis of the report are peer-reviewed
results published in scientific journals.
The report notes that scientific progress since the TAR
[Third Assessment Report] is based upon large amounts of new and
more comprehensive data, more sophisticated analyses of data,
improvements in understanding of processes and their simulation
in models, and more extensive exploration of uncertainty ranges.
On the question of whether humans are the cause of recent warming,
the new report is nearly conclusive. Improvements in computer
simulations have led the IPCC to conclude that the warming of
the past 50 years is very likely due to human activity.
This means the authors are more than 90 percent certain that recent
global warming is caused by the burning of fossil fuels, changes
in land use, and agriculture. The previous report concluded that
anthropogenic warming was only likely, meaning it
was more than 66 percent certain.
The burning of fossil fuels has been the primary source of
increases in carbon dioxidethe most significant contributor
to global warming. Atmospheric concentrations of carbon dioxide
rose to 379 parts per million (ppm) in 2005. This level by
far exceeds the natural range over the last 650,000 years (180
to 300 ppm) as determined from ice cores, according to the
report, and represents a great increase over the pre-industrial
value of 280 ppm. Concentrations of other greenhouse gasses
have also risen over the last century, with methane rising to
1774 parts per billion (ppb) and nitrous oxide rising to 319 ppb
in 2005. This is compared with pre-industrial levels of 715 ppb
and 270 ppb respectively.
The report states, Warming of the climate system is unequivocal,
citing observations of increases in global average air and
ocean temperatures, widespread melting of snow and ice, and rising
global mean sea level. Notably, 11 of the last 12
years (1995-2006) rank among the 12 warmest years in the instrumental
record of global surface temperature.
The report correlates an increase of intense tropical
cyclone activity in the North Atlantic since about 1970
with increases of tropical sea surface temperatures.
It also links increased temperatures and decreased precipitation
with more intense and longer droughts over wider areas since
the 1970s.
The human impact of climate change will be detailed in another
IPCC report to be released later this year. The summary released
February 2 deals only with The Physical Science Basis
portion of the IPCC assessment. From drafts obtained by the
Age, an Australian newspaper, between 1.1 billion and 3.2
billion people will suffer water scarcity as a result of climate
change. Also, between 200 million and 600 million could suffer
from food shortages and 7 million could be affected by costal
flooding. The poor will be most affected by climate change.
Although the summary is directed at policymakers, there is
little sign of a change in course among major contributors of
greenhouse gas emissions, such as the United States, Australia,
China, and India. In a press conference held in response to the
IPCC report, US Energy Secretary Samuel Bodman accepted the findings
but rejected any kind of mandatory caps of greenhouse gas emissions.
Instead he suggested emission reductions should be tied to economic
growth, and should be achieved through voluntary, market-based
products.
Bodman made the correct point that a self-imposed cap on emissions
in United States will lead to shifts in production where there
are no caps. In this statement, he expresses the logic of capitalism,
which seeks the most profitable means of production with little
regard for the long-term environmental consequences. Despite the
Bush-appointed officials boasts of investment in climate
research and energy technologies, greenhouse gas emissions have
continued to increase under the Bush administration.
Overall, the party affiliation of the resident of the White
House (Democrat or Republican) has not impacted trends in greenhouse
gas emissions. According to statistics contained in the Environmental
Protection Agencys 2006 report Inventory of U.S. Greenhouse
Gas Emissions and Sinks: 1990-2004, average yearly greenhouse
gas emissions increased by 1.6 percent a year under the Clinton-Gore.
These trends have largely continued under George W. Bush. As the
EPAs report notes, the driving factors in the increase in
emissions in the United States over the period 1990-2004 are a
growing domestic economy and increased emissions from transportation
activities and electricity generation. Although the EPA produces
an inventory of greenhouse gas emissions, as is required by the
United Nations Framework Convention on Climate Change, there is
no federal regulation to limit greenhouse gas emissions.
The IPCC has issued three previous reports, in 1990, 1995 and
2001. Governmental responses so far to the IPCCs continued
warnings have been largely symbolic. The only existing international
agreement to reduce emissions, the Kyoto protocol, is ineffective
and flawed in its conception. The formation of a new international
agreement that works to significantly reduce global greenhouse
gas emissions faces insurmountable challenges within the framework
of the nation-state system, which pits country against country
and subordinates the protection of the environment to the interests
of private profit.
See Also:
Scientists report rampant political interference
in climate research
[5 February 2007]
Kyotos Clean Development
Mechanism: global warming and its market fix
[13 January 2007]
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