Global temperature anomaly for past year

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Global temperature anomaly for past year
1. Area of warmer 20 times cooler
2. Farther out on warm scale than cool scale
3. Strongest warming in polar regions
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The Big Questions in Climate Change
1. Is it warmer (in Alaska)?
2. Is the warming consistent with greenhouse
gasses as a major part of the cause?
3. Are there detectable effects from the warming?
4. Are the effects significant - large in
magnitude?
5. Are there impacts to human well-being -
economic, social, etc?
6. Can awareness and planning help in dealing
with impacts?
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UNCERTAINTIES Temperature levels before 1000
AD?. Why were parts of the Arctic basin
warmer in the early 1940s than now?
Quantification of solar vs. greenhouse influence.
Global dimming.
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Overview of climate changes in the Arctic and
boreal regions
Daytime high temperatures in the warm season
have not increased much during the last 100 yrs
(yes during the last 50 yrs). Daily low
temperature in the warm season have increased 2
to 3.5 C. Winters are warmer (no big pool of
cold Arctic air) - later first snowfall and
freeze-up - fewer days of extreme cold (0, -20,
-40 F) - earlier break-up - greater flow during
winter (if good snow cover) - false springs
during winter. Convective thunderstorms in the
coastal region. Record heat/drought
interaction (low flows). More of yearly water
budget from intense (flashy) precipitation.
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Overview of climate-related changes in the Arctic
and boreal regions
Forest fires and insect outbreaks are
increasing. Tree growth is decreasing on
productive boreal sites. Tree growth is
increasing in most coastal sites and on marginal
boreal sites. Tundra is greening. Glaciers
are melting. Sea Ice is retreating and
thinning. Permafrost is warming, with some
thawing. Lakes are drying.
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1932 World series
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2005 predicted growth (actual weather summer
2004)
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Summer 2006
Forest Health Program Alaska Department of
Natural Resources, Division of Forestry Dr.
Robert Ott
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The tundra is greening
Satellite-observed photosynthetic trends across
boreal North America associated with climate and
fire disturbance. S. Goetz, A. Bunn, G. Fiske,
R. Houghton September, 2005. Proceedings of
the National Academy of Science
The boreal forest is stressed or dying
near zero
12 km X 12 km pixels Greenness (NDVI)
data 1982 - 2003
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Global temperature anomaly for May through
October 2004
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Canadian Climate Center scenario
scenario
2004
recorded
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Good and bad in relation to climate warming
Must be related to some specific desired
condition.
A human construct because nature per se has no
values.
Drastic global warmings and coolings are a
regular feature of the history of Earth before
the emergence of man.
If you identify what you value, then science
can tell you whether climate change is good for
that or bad for that.
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To understand climate change impact, the resource
management context is crucial.
Change produces both impacts and
opportunities.
Impacts are relatively low even for a large
magnitude of change in a resource if the goal is
to allow the resource to change in response to
a changing environment (park and wilderness
goals).
Impacts are large where people have made plans
and investments based on the expectation of
the availability or condition of the resource
(resource production goals).
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Solar Cycle sunspot number
Cycle 24
Cycle 23
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Outlook Solar variability contributing to
medium term, irregular warming influence 2007 -
2012
Cycle 24 (projected)
Cycle 23 (actual)
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Urban heat island effect?
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No urban heat island
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No urban heat island effect
100 increase in growing season length
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280 mm
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21.1 (elimination) - 17.1 (now) 4.0 (more to
go)
Annual precipitation (mm)
280 mm
July Temperature (oC)
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Productive white spruce stands in central Alaska
When summers are warm, the trees run out of
water and stop growing.
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Black spruce stands on ridge and gravelly sites
When summers are warm, the trees run out of
water and stop growing.
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Productive Alaska birch stands
When summers are warm, trees run out of water and
stop growing.
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Fingerprint of climate warming effect imposed
on the natural disturbance tree death system
1) greater frequency of disturbance.
2) more extensive areas of tree mortality in
disturbances.
3) greater intensity of disturbance resulting in
higher average levels of tree death within
outbreaks.
Result Change in regional tree species
composition or conversion from forest to
non-forest ecosystem within decades .
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Alaska, USA
Fire season 2004 2.71 million ha (Highest total
in 56-yr record)
(15 to 20 of forest land in the northeast 1/4
of Alaska)
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FIRES of 2004
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Alaska, USA
Fire season 2005 1.61 million ha (3rd highest
total in 56-yr record)
(another 7 to 10 of forest land in the
northeast 1/4 of Alaska)
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Alaska Yellow Cedar
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Alaska Yellow cedar decline
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The 1987 thaw and freeze event in southeast
Alaska
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Warm summers high fire years
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