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Rajendra K. Pachauri
Chairman IPCC
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IPCC
Remains Credible Despite Minor Errors
BY
IDN Global Desk 
The
Intergovernmental Panel on Climate Change (IPCC) has come under severe
attack for some minor errors in its extensive 2007 report on climate
change. But, on the whole, the IPCC’s conclusions remain indisputable:
Climate change is happening now and human activity is causing it.
There is no alternative for countries around the world to adapt to at
least some climate change, including sea level rise, changes in
precipitation, disruptions to agriculture, and species extinctions. But
if they dramatically reduce their emissions, the worst effects of
climate change can be staved off.
The Union of Concerned Scientists* has assembled a series of explanatory
backgrounders on specific allegations about the report, with a view to
setting the record straight.
WHAT IS THE IPCC?
The IPCC is the world's leading body for assessing climate science. It
was established in 1988 by the World Meteorological Organization (WMO)
and the UN Environment Programme (UNEP) in recognition of the problem of
global warming. Through the IPCC, climate experts from around the world
synthesize the most recent climate science findings every five to seven
years and present their report to the world's political leaders. Thus
far, the IPCC has issued comprehensive assessments in 1990, 1995, 2001
and 2007.
The IPCC's 2007 report is the most comprehensive synthesis of climate
change science to date. Experts from more than 130 countries working
over six years contributed to the assessment. More than 450 lead authors
received input from more than 800 contributing authors, and an
additional 2,500 experts reviewed the draft documents.
The 2007 report is comprised of three sections, or working groups, that
focus on the scientific basis of global warming (Working Group I), its
consequences (Working Group II), and options for mitigation (Working
Group III). The IPCC released summaries of the three working group
documents over the course of 2007, culminating in the publication of the
final "synthesis report" at the end of the year.
The inclusive and transparent process by which IPCC assessments are
developed, reviewed and accepted by experts and governments helps ensure
scientific credibility and value for informing officials when they
formulate climate policies. As with any human endeavor, errors are
possible. It is a testament to the quality of the IPCC that errors have
been few, and when identified, they have been corrected. A concerted
effort to improve the quality of the IPCC process is essential.
HIMALAYAN GLACIERS WON'T BE GONE BY 2035, BUT GLACIERS AROUND THE
WORLD ARE RETREATING.
The second of three 2007 IPCC reports included a statement that the
likelihood that Himalayan glaciers will disappear "by the year 2035
and perhaps sooner is very high." It is not clear how this
unsupported assertion made it into the report, although it was openly
challenged by some researchers during the review and editing process. On
January 20, the IPCC released a statement (pdf) on this issue. It says,
in part, "The Chair, Vice-Chairs, and Co-chairs of the IPCC regret
the poor application of well-established IPCC procedures in this
instance."
The claim was part of the full review of climate science and impacts
provided in the dense, 3,000-page report, but was not mentioned in its
highly visible summaries for policymakers. Presumably the working group
did not consider the 2035 Himalayan glaciers claim to be reliable enough
for its policymaker summary. The statement in the summary was much less
specific. "If current warming rates are maintained," it
stated, "Himalayan glaciers could decay at very rapid rates."
Given the expansive nature of the IPCC, it is not surprising to find
relatively minor errors. Such mistakes do not undermine the overall
conclusions of the organization's reports, which are subject to an
exhaustive review process.
WHAT SHOULD NOT GET LOST IS THE FACT THAT GLACIERS AROUND THE WORLD
ARE MELTING RAPIDLY.
A 2005 global survey of 442 glaciers from the World Glacier Monitoring
Service found that only 26 were advancing, 18 were stationary, and 398
were retreating. Overall, about 90 percent of the world's glaciers that
scientists have measured are shrinking as the planet warms.
Because scientific understanding of how fast snow and ice is responding
to global warming is still developing, the IPCC largely left the effect
of melting glaciers and ice sheets out of its sea-level rise projections
in 2007 and primarily considered the effects that thermal expansion has
on the ocean.
New analyses indicate that the shrinking land-based ice could lead to a
sea-level rise of 2.6 feet (0.8 meter) by the end of the century; and,
although 6.6 feet (2.0 meters) is less likely, it is still physically
possible.
Melting glaciers and the resulting sea-level rise are a threat to
coastal communities around the world. According to the U.S. Global
Change Research Program's 2009 review of climate impacts in the United
States, "Sea-level rise and storm surge place many U.S. coastal
areas at increasing risk of erosion and flooding, especially along the
Atlantic and Gulf Coasts, Pacific Islands, and parts of Alaska. Energy
and transportation infrastructure and other property in coastal areas
are very likely to be adversely affected."
Melting glaciers also will threaten drinking water supplies. An August
2008 Geophysical Research Letters study that examined the impact of the
melting Himalayan Naimona'nyi glacier concluded, "If Naimona'nyi is
characteristic of other glaciers in the region, alpine glacier meltwater
surpluses are likely to shrink much faster than currently predicted with
substantial consequences for approximately half a billion people."
THE IPCC GOT THE SCIENCE RIGHT ABOUT DROUGHT AND FIRE THREATS TO
AMAZON, BUT GOT ITS CITATIONS WRONG.
A sentence in Chapter 13 of the 2007 IPCC Fourth Assessment Report on
Impacts, Adaptation and Vulnerability states: "Up to 40 percent of
the Amazonian forests could react drastically to even a slight reduction
in precipitation; this means that the tropical vegetation, hydrology and
climate system in South America could change very rapidly to another
steady state, not necessarily producing gradual changes between the
current and the future situation."
In other words, global warming may be putting the Amazon basin at risk
of more frequent and severe droughts. In drought years, trees are more
likely to die and forests become more susceptible to fires. In wet
years, fires often stop at the forests' edge because the forest soil is
so moist.
The passage cites a report from the World Wildlife Fund (WWF) and the
International Union for Conservation of Nature (IUCN), an organization
that includes more than 1,000 government and NGO member organizations,
and nearly 11,000 volunteer scientists in more than 160 countries. (News
stories have inaccurately described the report as a sole product of WWF.)
It would have been preferable for the IPCC to have cited the original
scientific peer-reviewed literature rather than the WWF-IUCN report.
Further, the WWF-IUCN report was scientifically correct, but it did not
cite the correct papers by Dan Nepstad, a senior scientist at the Woods
Hole Research Center on Cape Cod, and his colleagues.
John Cook, the editor of SkepticalScience.com, summarized the citation
error in the WWF-IUCU report:
"The WWF correctly states that 630,000 km2 of forests were severely
drought stressed in 1998 -- this figure comes from Nepstad et al. 1999.
However, the 40 percent figure comes from several other papers by the
same author that the WWF failed to cite. A 1994 paper estimated that
around half of the Amazonian forests lost large portions of their
available soil moisture during drought (Nepstad et al. 1994). In 2004,
new rainfall data showed that half of the forest area of the Amazon
Basin had either fallen below, or was very close to, the critical level
of soil moisture below which trees begin to die (Nepstad et al. 2004).
The results from these papers are consistent with the original
statement: 'Up to 40 percent of the Brazilian forest is extremely
sensitive to small reductions in the amount of rainfall.'"
It is also worth noting that Nepstad and other researchers further
confirmed the link between drought and fire in papers published after
the IPCC's deadline for research that could be included in this section
of its 2007 report.
Cook continues:
"Subsequent research has provided additional confirmation of the
Amazonian forest's vulnerability to drought. Field measurements of the
soil moisture critical threshold found that tree mortality rates
increase dramatically during drought (Nepstad et al. 2007). Another
study measured the effect of the intense 2005 drought on Amazonian
biomass (Phillips et al. 2009). The drought caused massive tree
mortality leading to a fall in biomass. This turned the region from a
large carbon sink to a carbon producer. The paper concluded that 'such
events appear capable of strongly altering the regional carbon balance
and thereby accelerating climate change.'"
While the IPCC should have cited the original peer-reviewed literature,
not a summary of that literature by WWF and IUCN, the basic science was
sound. And regardless of how the IPCC cited the references, tropical
forests are increasingly vulnerable to drought and fire because of
climate change as well as from forest degradation from destructive
logging practices.
MORE EXTREME WEATHER FROM CLIMATE CHANGE WILL CAUSE EXPENSIVE DAMAGE
There is a clear scientific consensus -- based on the conclusions of
many peer-reviewed papers -- that climate change is causing an increase
in storms with heavy precipitation. This is due in part because warmer
air retains more moisture, setting the stage for heavier rain and snow
storms in areas that typically experience rain or snow. Between 1958 and
2007, New England saw a 67 percent increase in heavy precipitation
events and the Midwest experienced a 31 percent increase, according to
the 2009 federal report "Global Climate Change Impacts in the
United States." The report documented a 20 percent average increase
for the entire country.
The 2007 IPCC report also was clear about how climate change would
affect hurricanes. It concluded that hurricane intensity worldwide
likely would increase, and that there could be fewer weak hurricanes.
The report included numerous references to peer-reviewed studies that
draw this conclusion, which was confirmed by studies conducted by the
National Oceanic and Atmospheric Administration and other institutions.
The science linking climate change to increased severity of extreme
weather is well-substantiated in peer-reviewed literature. Even so, some
contrarians have recently cited another, older controversy to try to
give the false impression that these findings are in question. That
controversy centers on how the 2007 report characterized the economic
cost of an increase in severe weather. Contrarians specifically point to
a complaint by Roger Pielke Jr., a University of Colorado environmental
studies professor, that the 2007 report misrepresented the reasons why
economic losses from natural disasters have significantly increased over
the years. Pielke says that the primary drivers for increased costs are
economic factors, such as changes in wealth and population along the
coasts.
The IPCC report did not dispute that fact, and it prominently cited
Pielke's research. It also cited one study that suggested that factors
other than economic ones may be driving costs, but included a number of
caveats in that citation. This is in keeping with the IPCC's task of
presenting a balanced view of the literature.
Specifically, the report concluded in its "Summary for Policy
Makers" section: "Costs and benefits of climate change for
industry, settlement [cities and towns] and society will vary widely by
location and scale. In the aggregate, however, net effects will tend to
be more negative the larger the change in climate." And it found:
"Where extreme weather events become more intense and/or more
frequent, the economic and social costs of those events will increase,
and these increases will be substantial in the areas most directly
affected."
Pielke specifically objected to the IPCC including unpublished material
on economic costs of natural disasters in its 2007 report. This
practice, however, is not unusual for the IPCC. IPCC procedures state
that "…it is increasingly apparent that materials relevant to
IPCC reports, in particular, information about the experience and
practice of the private sector in mitigation and adaptation activities,
are found in sources that have not been published or peer-reviewed
(e.g., industry journals, internal organizational publications, non-peer
reviewed reports or working papers of research institutions, proceedings
of workshops, etc)." The IPCC provides guidelines for the inclusion
of such research, including clear citation. In any case, more published
research is needed on the economic costs of climate change.
CHINESE TEMPERATURE RECORDS ARE RELIABLE AND CONSISTENT WITH GLOBAL
WARMING
Climate contrarians are falsely claiming Eastern Chinese temperature
data first published in a 1990 Nature paper is compromised by the
"urban heat island" effect. The term refers to the fact that
buildings and asphalt are darker than surrounding countryside, often
making cities and population centers hotter. Scientists have studied
this effect since the mid-1800s and it is extensively referenced in the
scientific literature. Overall, climate science indicates that the urban
heat island effect has no bearing on global temperature trends and is
insignificant compared to other adjustments routinely made to make
temperature records more accurate.
When scientists measure global warming, they examine how much
temperatures have changed over time. For instance, an urban station may
have warmer thermometer readings compared with a rural station in the
region, but global warming will cause temperatures to rise at both
stations. To determine trends, scientists compare the difference between
the temperatures at stations today and their average temperatures in the
past.
Scientists worldwide, including those at leading American institutions,
routinely correct station data for changes such as shifts in station
location, different elevation, different time of daily observation,
different latitudes, and instrument changes over time. For example,
after such adjustments for stations across the United States, there was
no detectable difference between urban and rural stations comparisons in
each region.
Climate contrarians are using the Eastern Chinese temperature data to
try to link manufactured controversies over citations in the IPCC's 2007
report and the content of stolen emails from the University of East
Anglia's (UEA) Climatic Research Unit that were published online late
last November. UEA has issued a statement rebutting these claims and
addressing some freedom of information concerns raised by a recent story
in the Guardian, a British newspaper. According to UCS, UEA could do
more to be transparent, particularly by making relevant documents
related to these and other charges easily accessible online.
The 2007 IPCC report does cite papers on the Eastern Chinese data --
along with thousands of other papers. And some of the stolen emails
included passages that mentioned the Chinese data. But just like the
previous manufactured controversies, these accusations shed little light
on the science in question.
In fact, the Eastern China temperature data referenced in the Guardian
article and other news stories are reliable and are only a minuscule
part of the global temperature record data that indicate that the
Earth's average temperatures are rising. It should be noted the
"urban heat island" effect does not in any way affect the vast
number of temperature records measured outside of cities or in the
ocean.
Eastern China is warming in a way consistent with the rise in global
average temperatures. The 1990 Nature paper in question was backed up by
several other studies, as the University of East Anglia noted.
When University of East Anglia Climatic Research Unit Director Phil
Jones and other researchers conducted their 1990 research, they found
little difference in temperature between 42 urban stations and 42
suburban temperature stations in Eastern China. A 2008 study by Jones
and other researchers, which examined 728 temperatures stations in
Eastern China, confirmed that there was an insignificant difference
between temperatures in urban and suburban areas.
However, by comparing the difference between all the Eastern China land
stations to the nearby ocean temperatures, the 2008 paper did find
significant warming from increased urbanization on the land -- 0.1
degrees Celsius per decade between 1951 and 2004. Overall, the study
found Eastern China warmed 0.8 degrees Celsius over the same time period
largely due to global warming. Chinese temperature records are reliable
and consistent with global warming.
[Source:
IDN-InDepthNews
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