On 4/9/07, David Opderbeck <dopderbeck@gmail.com> wrote:
> The glory of a broad consensus-seeking political process is precisely that
> extremes tend to get toned down and precipitous action tends to get tabled.
> Lead with a strength -- the IPCC reports, even after the influence of
> skeptical regimes such as the U.S. and China, demand firm action to combat
> warming -- and even skeptics have to give some ground. Lead with whines
> about the fact that the political process you agreed to participate in isn't
> giving you all the results you want, and you give the skeptics and cynics
> ammunition.
Fair enough. Here's what survived the attempted political
manipulation. I added notes where there were attempts to soften the
science.
NCAR summary of the IPCC Working Group II
http://www.ucar.edu/news/features/climatechange/faqs-wg2-spm.jsp
Note also the following link that show what has happened in climate
modelling since the ten-year-old story posted by another person.
http://www.ucar.edu/news/features/climatechange/ccsm-illus.jsp
Highlights from the IPCC Working Group II Summary for Policymakers of
"Climate Change 2007: Impacts, Adaptation and Vulnerability"
Below are some of the key statements in the Summary for Policymakers
from Working Group II of the 2007 IPCC Fourth Assessment Report. The
summary was released on Friday, April 6, 2007, and is available in
full on the IPCC Working Group II Web site. Working Group III will
issue its summary in May, and the full reports for all three working
groups will be released later in 2007 (see box at right).
The working group has assigned confidence levels, either in the text
or in parentheses, to many of its findings. Spelling and punctuation
have been adapted to Standard American style.
How is climate change affecting natural and human-managed systems?
"Observational evidence from all continents and most oceans shows that
many natural systems are being affected by regional climate changes,
particularly temperature increases." [RDB note: Original showed this
as very high confidence]
"With regard to changes in snow, ice and frozen ground (including
permafrost) , there is high confidence that natural systems are
affected. Examples are:
• enlargement and increased numbers of glacial lakes;
• increasing ground instability in permafrost regions, and rock
avalanches in mountain regions;
• changes in some Arctic and Antarctic ecosystems, including those
in sea-ice biomes, and also predators high in the food chain."
"Based on growing evidence, there is high confidence that the
following types of hydrological systems are being affected around the
world:
• increased run-off and earlier spring peak discharge in many
glacier- and snow-fed rivers
• warming of lakes and rivers in many regions, with effects on
thermal structure and water quality."
"There is very high confidence, based on more evidence from a wider
range of species, that recent warming is strongly affecting
terrestrial biological systems, including such changes as:
• earlier timing of spring events, such as leaf-unfolding, bird
migration and egg-laying;
• poleward and upward shifts in ranges in plant and animal species."
What do we know about future impacts?
How will future impacts vary by region?
View an interactive map of potential impacts of climate change.
http://www.ucar.edu/news/features/climatechange/regionalimpacts.jsp
The selected impacts are based on the region-by-region analysis
conducted by IPCC Working Group II. Click here or on the image to open
a Web page with the enlarged, interactive map. ((c)UCAR. News media
terms of use*)
"Magnitudes of impact can now be estimated more systematically for a
range of possible increases in global average temperature."
Water:
"By mid-century, annual average river runoff and water availability
are projected to increase by 10-40% at high latitudes and in some wet
tropical areas, and decrease by 10-30% over some dry regions at
mid-latitudes and in the dry tropics, some of which are presently
water stressed areas. In some places and in particular seasons,
changes differ from these annual figures (high confidence)."
"Drought-affected areas will likely increase in extent. Heavy
precipitation events, which are very likely to increase in frequency,
will augment flood risk (high confidence)."
"In the course of the century, water supplies stored in glaciers and
snow cover are projected to decline, reducing water availability in
regions supplied by meltwater from major mountain ranges, where more
than one-sixth of the world population currently lives (high
confidence)."
Ecosystems:
"The resilience of many ecosystems is likely to be exceeded this
century by an unprecedented combination of climate change, associated
disturbances (e.g., flooding, drought, wildfire, insects, ocean
acidification), and other global change drivers (e.g., land use
change, pollution, over-exploitation of resources) (high confidence).
"
"Approximately 20–30% of plant and animal species assessed so far are
likely to be at increased risk of extinction if increases in global
average temperature exceed 1.5–2.5°C.[2.7–4.5°F] (medium confidence)."
Food:
"Crop productivity is projected to increase slightly at mid to high
latitudes for local mean temperature increases of up to 1–3°C
[1.8–5.4°F] depending on the crop, and then decrease beyond that in
some regions (medium confidence)."
"At lower latitudes, especially seasonally dry and tropical regions,
crop productivity is expected to decrease for even small local
temperature increases, (1–2°C [1.8–3.6°F]), which would increase risk
of hunger (medium confidence)."
Coastal systems and low-lying areas:
"Increases in sea surface temperature of about 1 to 3°C [1.8 to
5.4°F] are projected to result in more frequent coral bleaching events
and widespread mortality, unless there is thermal adaptation or
acclimatization by corals (very high confidence)."
"Many millions more people are projected to be flooded every year due
to sea-level rise by the 2080s. Those densely-populated and low-lying
areas where adaptive capacity is relatively low, and which already
face other challenges such as tropical storms or local coastal
subsidence, are especially at risk. The numbers affected will be
largest in the mega-deltas of Asia and Africa while small islands are
especially vulnerable (very high confidence)."
Industry, settlement and society
"Costs and benefits of climate change for industry, settlement, 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 (high confidence)."
"Poor communities can be especially vulnerable, in particular those
concentrated in high-risk areas. They tend to have more limited
adaptive capacities, and are more dependent on climate-sensitive
resources such as local water and food supplies (high confidence)."
Health:
"Projected climate change-related exposures are likely to affect the
health status of millions of people, particularly those with low
adaptive capacity, through:
• increases in malnutrition and consequent disorders, with
implications for child growth and development;
• increased deaths, disease and injury due to heat waves, floods,
storms, fires and droughts;
• the increased burden of diarrhoeal disease;
• the increased frequency of cardio-respiratory diseases due to
higher concentrations of ground level ozone related to climate change;
and,
• the altered spatial distribution of some infectious disease
vectors (high confidence)."
"Climate change is expected to have some mixed effects, such as the
decrease or increase of the range and transmission potential of
malaria in Africa (high confidence)."
"Studies in temperate areas have shown that climate change is
projected to bring some benefits, such as fewer deaths from cold
exposure. Overall it is expected that these benefits will be
outweighed by the negative health effects of rising temperatures
world-wide, especially in developing countries (high confidence)."
For more information on projected impacts, sector-by-sector, see the
table detailing those impacts and their likelihood of occurrence in
Table SPM-2 on page 16 of the WG2 Summary for Policymakers (PDF).
http://www.ipcc.ch/SPM2feb07.pdf
What are the largest impacts that might happen, especially after 2100?
"There is medium confidence that at least partial deglaciation of the
Greenland ice sheet, and possibly the West Antarctic ice sheet, would
occur over a period of time ranging from centuries to millennia for a
global average temperature increase of 1–4°C [1.8–7.2°F] (relative to
1990–2000), causing a contribution to sea-level rise of 4–6 meters
[13–20 feet] or more."
"Based on climate model results, it is very unlikely that the
Meridional Overturning Circulation (MOC) in the North Atlantic [known
as the ocean conveyor belt] will undergo a large abrupt transition
during the 21st century. Slowing of the MOC this century is very
likely, but temperatures over the Atlantic and Europe are projected to
increase nevertheless, due to global warming."
What do we know about responding to climate change?
"Some adaptation is occurring now, to observed and projected future
climate change, but on a limited basis."
"Adaptation will be necessary to address impacts resulting from the
warming which is already unavoidable due to past emissions."
"However, adaptation alone is not expected to cope with all the
projected effects of climate change, and especially not over the long
run as most impacts increase in magnitude." [RDB Note: the obvious
conclusion that mitigation is also necessary was deleted by the
politicians.]
"A wide array of adaptation options is available, but more extensive
adaptation than is currently occurring is required to reduce
vulnerability to future climate change. There are barriers, limits and
costs, but these are not fully understood."
"Vulnerability to climate change can be exacerbated by the presence of
other stresses."
". . .[T]he projected impacts of climate change can vary greatly due
to the development pathway assumed. For example, there may be large
differences in regional population, income and technological
development under alternative scenarios, which are often a strong
determinant of the level of vulnerability to climate change."
"Sustainable development can reduce vulnerability to climate change by
enhancing adaptive capacity and increasing resilience. At present,
however, few plans for promoting sustainability have explicitly
included either adapting to climate change impacts, or promoting
adaptive capacity."
"A portfolio of adaptation and mitigation measures can further
diminish the risks associated with climate change."
"This Assessment makes it clear that the impacts of future climate
change will be mixed across regions. For increases in global mean
temperature of less than 1 to 3°C [1.8 to 5.4°F] above 1990 levels,
some impacts are projected to produce benefits in some places and some
sectors, and produce costs in other places and other sectors. It is,
however, projected that some low latitude and polar regions will
experience net costs even for small increases in temperature. It is
very likely that all regions will experience either declines in net
benefits or increases in net costs for increases in temperature
greater than about 2 to 3°C [3.6 to 5.4°F]."
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Received on Tue Apr 10 09:15:49 2007
This archive was generated by hypermail 2.1.8 : Tue Apr 10 2007 - 09:15:49 EDT