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CHAPTER 26 CLIMATE CHANGE
WHEN THE
TREES LEAVE
Scientists grapple with a shifting climate
26
WHEN THE TREES LEAVE
Scientists grapple with a shifting climate
Evidence for climate change is
overwhelming, and human activity is
the main driver.
Changes throughout our natural
environment, from species diversity to
declining human health on a
worldwide scale are in our own hands.
Information and literacy will help us
make sound policy
decisions.
Main Concept
26
WHEN THE TREES LEAVE
Scientists grapple with a shifting climate
At the end of this chapter you will know:
• The difference between climate and
weather.
• The evidence for climate change and
anthropogenic drivers is overwhelming.
• Acknowledging human factors and
making changes is imperative.
Learning
Outcomes
26
WHEN THE TREES LEAVE
Scientists grapple with a shifting climate
Climate change is causing ice in the lakes
of northern forests to melt earlier in the
year, winters are coming later, some
species of trees are dying off, and other
species are popping up in unexpected
places.
Forests are at risk of becoming scrublands
or savanna, prairies in Africa and the
Americas are becoming deserts, coral reefs
are becoming bleached, and change is
happening everywhere at unprecedented
speed.
Case: Ham
Lake in North
Woods of
Minnesota
26
WHEN THE TREES LEAVE
Scientists grapple with a shifting climate
Climate change is causing ice in the lakes
of northern forests to melt earlier in the
year, winters are coming later, some
species of trees are dying off, and other
species are popping up in unexpected
places.
Forests are at risk of becoming scrublands
or savanna, prairies in Africa and the
Americas are becoming deserts, coral reefs
are becoming bleached, and change is
happening everywhere at unprecedented
speed.
Case: Ham
Lake in North
Woods of
Minnesota
26
Climate is not the same thing as weather
Temperature on a given day is part
of what we refer to as weather.
The predictions and range of
conditions we expect is based on
climate.
Weather is short-term and
geographically limited, while
climate is the larger, long-term
picture.
No single weather event can be
attributed to global warming.
However, the rapidly shifting range
of temperatures that are being
recorded around the world are
indications of climate change
associated with global warming.
Dr. Lee Frelich of the
University of Minnesota
surveying the damage following the 75,000
acre fire at Ham Lake.
http://www.forestry.umn.edu/People/Frelich/ind
ex.html
26
Climate is not the same thing as weather
Range shifts have happened
before.
As the North American ice cap
retreated 12,000 years ago, tree
species range shifted northward at
a rate of 50 km per century.
About 6000 years ago, another
tree range migration occurred—
this time south and west.
Instead of having thousand of
years to adapt as with past climate
changes, tree species today might
have only a few decades in which
to adapt or die.
Dr. Lee Frelich of the
University of Minnesota
surveying the damage following the 75,000
acre fire at Ham Lake.
http://www.forestry.umn.edu/People/Frelich/ind
ex.html
26
Evidence of global climate change abounds
TERMS TO KNOW:
Climate change
Weather
Climate
Consider this:
Birch trees, long established in the Minnesota north woods are dying as growing
seasons get longer and soil temperatures rise.
Red maple, common in Louisiana, is becoming well established in Minnesota.
Spring, marked by budding, is two weeks or more ahead of historic averages for the
last two decades.
The National Oceanic and Atmospheric Administration (NOAA) has recorded global
average land temperatures almost 2oF higher than the twentieth-century average
and sea surface temperatures as much as 5oF higher in some parts of the world.
26
Evidence of global climate change abounds
TERMS TO KNOW:
Climate change
Weather
Climate
Consider this:
Birch trees, long established in the Minnesota north woods are dying as growing
seasons get longer and soil temperatures rise.
Red maple, common in Louisiana, is becoming well established in Minnesota.
Spring, marked by budding, is two weeks or more ahead of historic averages for the
last two decades.
The National Oceanic and Atmospheric Administration (NOAA) has recorded global
average land temperatures almost 2oF higher than the twentieth-century average
and sea surface temperatures as much as 5oF higher in some parts of the world.
26
Evidence of global climate change abounds
TERMS TO KNOW:
Climate change
Weather
Climate
Consider this:
Birch trees, long established in the Minnesota north woods are dying as growing
seasons get longer and soil temperatures rise.
Red maple, common in Louisiana, is becoming well established in Minnesota.
Spring, marked by budding, is two weeks or more ahead of historic averages for the
last two decades.
The National Oceanic and Atmospheric Administration (NOAA) has recorded global
average land temperatures almost 2oF higher than the twentieth-century average
and sea surface temperatures as much as 5oF higher in some parts of the world.
26
TERMS TO KNOW:
Climate change
Weather
Climate
Small
changes
have big
impact.
Icebergs 200feet tall,
formerly part
of the
Greenland Ice
Sheet, now
float into the
North Atlantic
Ocean.
Evidence of global climate change abounds
26
Evidence of global climate change abounds
Just a few degrees warmer and we see big
effects—especially in the Arctic.
Temperature change is not evenly
distributed. Researchers evaluated
weather patterns of Ellismere Island in the
Arctic and found that
spring and summer
temperatures were
20−29oF higher than
in previous years.
This difference is
equivalent to locations
1000−1400
miles farther south.
Rising sea levels have already displaced
hundreds of thousands of people.
26
Evidence of global climate change abounds
26
Evidence of global climate change abounds
Warmer temperatures
can be expected to
lead to weather
extremes.
26
Evidence of global climate change abounds
26
Evidence of global climate change abounds
26
Evidence of global climate change abounds
26
Evidence of global climate change abounds
26
A variety of factors affect climate
TERMS TO KNOW:
Greenhouse gases
Greenhouse effect
Radiative forcer
Albedo
Positive feedback
loops
Greenhouse gases each
have different abilities to
trap heat, expressed as
CO2 equivalents.
Greenhouse gases include carbon dioxide, methane, and nitrous oxide. These
gases maintain the Earth’s temperature—a good thing! Unfortunately, since the
middle of the twentieth century, evidence of an enhanced greenhouse effect from
the use of fossil fuels started to mount.
26
A variety of factors affect climate
TERMS TO KNOW
Greenhouse gases
Greenhouse effect
Radiative forcer
Albedo
Positive feedback
loops
Greenhouse gases each
have different abilities to
trap heat, expressed as
CO2 equivalents.
Greenhouse gases include carbon dioxide, methane, and nitrous oxide. These
gases maintain the Earth’s temperature—a good thing! Unfortunately, since the
middle of the twentieth century, evidence of an enhanced greenhouse effect from
the use of fossil fuels started to mount.
26
A variety of factors affect climate
TERMS TO KNOW:
Greenhouse gases
Greenhouse effect
Radiative forcer
Albedo
Positive feedback
loops
The greenhouse gases are one type of
radiative factor—something that alters the
balance of incoming solar radiation with heat
that escapes out into space.
Another influence is the ability of a surface to
reflect away solar radiation. This factor,
albedo, comes into play as glacier ice is lost
along with its role in reflecting light.
26
A variety of factors affect climate
TERMS TO KNOW:
Greenhouse gases
Greenhouse effect
Radiative forcer
Albedo
Positive feedback
loops
The greenhouse gases are one type of
radiative factor—something that alters the
balance of incoming solar radiation with heat
that escapes out into space.
Another influence is the ability of a surface to
reflect away solar radiation. This factor,
albedo, comes into play as glacier ice is lost
along with its role in reflecting light.
26
A variety of factors affect climate
TERMS TO KNOW:
Greenhouse gases
Greenhouse effect
Radiative forcer
Albedo
Positive feedback
loops
The greenhouse gases are one type of
radiative factor—something that alters the
balance of incoming solar radiation with heat
that escapes out into space.
Another influence is the ability of a surface to
reflect away solar radiation. This factor,
albedo, comes into play as glacier ice is lost
along with its role in reflecting light.
26
A variety of factors affect climate
As surfaces with high albedo are replaced
with low-albedo surfaces, warming
occurs and positive feedback is triggered.
Monitoring CO2 released from thawing
permafrost in Alaska – long-term increases
of atmospheric loading of CO2.
Positive and negative feedback loops
influence warming and cooling of the planet.
26
A variety of factors affect climate
To model and make predictions about the future climate, scientists use a wide
variety of clues from ice and sediment cores, tree rings, coral reefs, and fossils.
Other natural forces include volcanic eruptions and sunspot cycles. Predictable
long-term cycles of the Earth’s position relative to the Sun—Milanovitch cycles—
also played an important part in earlier climate-change events.
26
A variety of factors affect climate
To model and make predictions about the future climate, scientists use a wide
variety of clues from ice and sediment cores, tree rings, coral reefs, and fossils.
Other natural forces include volcanic eruptions and sunspot cycles. Predictable
long-term cycles of the Earth’s position relative to the Sun—Milanovitch cycles—
also played an important part in earlier climate-change events.
26
A variety of factors affect climate
To model and make predictions about the future climate, scientists use a wide
variety of clues from ice and sediment cores, tree rings, coral reefs, and fossils.
Other natural forces include volcanic eruptions and sunspot cycles. Predictable
long-term cycles of the Earth’s position relative to the Sun—Milanovitch cycles—
also played an important part in earlier climate-change events.
26
A variety of factors affect climate
To model and make predictions about the future climate, scientists use a wide
variety of clues from ice and sediment cores, tree rings, coral reefs, and fossils.
Other natural forces include volcanic eruptions and sunspot cycles. Predictable
long-term cycles of the Earth’s position relative to the Sun—Milanovitch cycles—
also played an important part in earlier climate-change events.
26
A variety of factors affect climate
Direct and indirect temperature measurements are used
to measure change over time.
Readings from Mauna Loa laboratory go back to 1958,
when Charles Keeling began taking precise CO2 readings.
CO2 gas bubbles from ice cores can also be used to
estimate past levels.
26
A variety of factors affect climate
Direct and indirect temperature measurements are used
to measure change over time.
Readings from Mauna Loa laboratory go back to 1958
when Charles Keeling began taking precise CO2 readings.
CO2 gas bubbles from ice cores can also be used to
estimate past levels.
26
A variety of factors affect climate
A comparison of
historic CO2 levels and
temperatures as
determined from the
Antarctic Vostok ice
core, show that the two
parameters have been
closely aligned over the
past 400,000 years.
The relationship between CO2 and temperature is one of both cause and effect.
In the far past, natural events triggered warming, resulting in the release of more
CO2, which then caused even more warming. Regardless of the reason for the
release of extra greenhouse gases, temperatures change as CO2 increases and
decreases.
26
Current climate change has both human and natural
causes
TERMS TO KNOW:
Anthropogenic
Intergovernmental
Panel on Climate
Change (IPCC)
Computer models take factors known to have affected past
climates to see what might be responsible for recent warming.
The Intergovernmental Panel on Climate Change
(IPCC) is made up of thousands of scientists from
around the world who evaluate research in climate
science. They agree that the Earth’s atmosphere
is changing dramatically and with alarming speed.
A thin slice of ice from an ice core from Antarctica. The core contains trapped air bubbles that can
reveal information about the atmosphere and temperatures of the past.
26
Current climate change has both human and natural
causes
TERMS TO KNOW
Anthropogenic
Intergovernmental
Panel on Climate
Change (IPCC)
Computer models take factors known to have affected past
climates to see what might be responsible for recent warming.
The Intergovernmental Panel on Climate Change
(IPCC) is made up of thousands of scientists from
around the world who evaluate research in climate
science. They agree that the Earth’s atmosphere
is changing dramatically and with alarming speed.
A thin slice of ice from an ice core from Antarctica. The core contains trapped air bubbles that can
reveal information about the atmosphere and temperatures of the past.
26
Current climate change has both human and natural
causes
NASA satellite reveals that 2011’s minimum sea ice extent in the Arctic Ocean,
reached on September 9, 2011, as depicted here, was far smaller than the 30-year
average (yellow) and opened up Northwest Passage shipping lanes (in red).
26
Some tree species are already migrating north; that
doesn’t mean they will survive
TERMS TO KNOW:
Anthropogenic
Intergovernmental Panel on Climate Change
(IPCC)
Species have evolved to live
and thrive in a certain habitat.
If the climate is changing
enough to alter ecosystems,
we expect to see species
responding by changing
where they live or the timing
of important temperaturedependent biological events.
26
Some tree species are already migrating north; that
doesn’t mean they will survive
TERMS TO KNOW:
Anthropogenic
Intergovernmental Panel on Climate Change
(IPCC)
26
Some tree species are already migrating north; that
doesn’t mean they will survive
TERMS TO KNOW:
Anthropogenic
Intergovernmental Panel on Climate Change
(IPCC)
26
Some tree species are already migrating north; that
doesn’t mean they will survive
TERMS TO KNOW:
Anthropogenic
Intergovernmental Panel on Climate Change
(IPCC)
26
Some tree species are already migrating north; that
doesn’t mean they will survive
TERMS TO KNOW:
Anthropogenic
Intergovernmental Panel on Climate Change
(IPCC)
26
Some tree species are already migrating north; that
doesn’t mean they will survive
TERMS TO KNOW:
Anthropogenic
Intergovernmental Panel on Climate Change
(IPCC)
Species’ responses, such as
shifting ranges or earlier
blooming and hatching, may
be the best evidence that
climate is actually changing.
It is unlikely that these
temperature-dependent
events would change in this
way if the planet were not
getting warmer.
26
Some tree species are already migrating north; that
doesn’t mean they will survive
TERMS TO KNOW:
Anthropogenic
Intergovernmental Panel on Climate Change
(IPCC)
The blue-gray gnatcatcher has
moved more than 300 km north
since the 1970s.
26
Some tree species are already migrating north; that
doesn’t mean they will survive
TERMS TO KNOW:
Anthropogenic
Intergovernmental Panel on Climate Change
(IPCC)
Sugar maple trees are moving north.
26
Some tree species are already migrating north; that
doesn’t mean they will survive
TERMS TO KNOW:
Anthropogenic
Intergovernmental Panel on Climate Change
(IPCC)
Winter temperatures are no longer low
enough to kill off bark beetles.
26
Climate change has environmental, health, and
economic consequences
As forests change to savanna or as losses
due to fires outside of the normal cycle
continue to mount, the direct economic
impact for the Boundary Waters area
around Ham Lake, Minnesota, alone can be
expected to top $240 million in lost wages.
No longer will the area be able to support
wildlife—moose, lynx, boreal owls—
invaluable on their own and integral to the
ecosystem functioning of
northern forests.
Forests stabilize soil and
clear water of pollutants.
Continued losses also play
into a positive feedback
loop that will accelerate climate change.
26
Confronting climate change is challenging
TERMS TO KNOW:
Mitigation
Carbon taxes
Precautionary principle
Resistance forestry is a new approach that uses
techniques aimed at maintaining existing species
in their current locations, despite the shifting
climate.
Planned burning mimics natural cycles and
planting seeds instead of saplings builds tougher
populations. Field-grown seedlings are hardier
and have a better chance of surviving changes.
Minimizing the damage is one strategy; limiting
the amount of CO2 entering the atmosphere is
another.
Researchers Pacala and Socolow from Princeton
University have propose the “stabilization
wedge,” whereby any eight of fifteen steps
would stabilize in the atmosphere.
26
Confronting climate change is challenging
TERMS TO KNOW:
Mitigation
Carbon taxes
Precautionary principle
Resistance forestry is a new approach that uses
techniques aimed at maintaining existing species
in their current locations, despite the shifting
climate.
Planned burning mimics natural cycles and
planting seeds instead of saplings builds tougher
populations. Field-grown seedlings are hardier
and have a better chance of surviving changes.
Minimizing the damage is one strategy; limiting
the amount of CO2 entering the atmosphere is
another.
Researchers Pacala and Socolow from Princeton
University have propose the “stabilization
wedge,” whereby any eight of fifteen steps
would stabilize in the atmosphere.
26
TERMS TO KNOW:
Mitigation
Carbon taxes
Precautionary principle
Confronting climate change is challenging
Minimizing the damage is one strategy; limiting the
amount of CO2 entering the atmosphere is another.
The IPCC has several climate-change response scenarios
that predict how much the climate will change based on
how the human population responds.
26
Confronting climate change is challenging
TERMS TO KNOW;
Mitigation
Carbon taxes
Precautionary principle
Researchers Pacala and Socolow from Princeton University
have propose the “stabilization wedge,” whereby any eight
of fifteen steps would stabilize in the atmosphere.
26
Confronting climate change is challenging
TERMS TO KNOW
Mitigation
Carbon taxes
Precautionary principle
Researchers Pacala and Socolow from Princeton University
have propose the “stabilization wedge,” whereby any eight
of fifteen steps would stabilize in the atmosphere.
26
Confronting climate change is challenging
TERMS TO KNOW
Mitigation
Carbon taxes
Precautionary principle
Researchers Pacala and Socolow from Princeton University
have propose the “stabilization wedge,” whereby any eight
of fifteen steps would stabilize in the atmosphere.
26
Confronting climate change is challenging
TERMS TO KNOW
Mitigation
Carbon taxes
Precautionary principle
Researchers Pacala and Socolow from Princeton University
have propose the “stabilization wedge,” whereby any eight
of fifteen steps would stabilize in the atmosphere.
26
TERMS TO KNOW:
Mitigation
Carbon taxes
Precautionary principle
Change is coming. Resistance
buys some time, but ultimately,
adaptation will be required.
How can we ensure an
adequate water supply?
What do we need to plant as
our ability to produce food
becomes stressed?
Can or should we relocate
trees in anticipation of where
they might survive?
Confronting climate change is challenging
26
TERMS TO KNOW:
Adaptation
Impact: With a slight
overall temperature
increase, crop
production can be
expected to increase.
With greater
increases, crop yields
will fall drastically.
Adaptation: Erosioncontrol techniques
and choosing crops to
fit the new conditions.
Mitigation might not be enough
26
TERMS TO KNOW:
Adaptation
Impact: The
proportion of land area
in severe drought is
projected to increase
from 1−3% today to
30% by 2090.
Adaptation: Focus on
methods to capture
and conserve water.
Practice pollution
prevention to increase
and protect water
supplies.
Mitigation might not be enough
26
TERMS TO KNOW:
Adaptation
Impact: The
proportion of land
area in severe drought
is projected to
increase from 1−3%
today to 30% by 2090.
Adaptation: Focus on
methods to capture
and conserve water.
Practice pollution
prevention to increase
and protect water
supplies.
Mitigation might not be enough
26
TERMS TO KNOW:
Adaptation
Impact: The spread of
waterborne
pathogens should
lead to increased
incidence of infectious
disease.
Adaptation: Improve
disease surveillance,
implement sanitation
improvements in
flood-prone areas,
and establish
emergency action
plans.
Mitigation might not be enough
26
TERMS TO KNOW:
Adaptation
Impact: Some species
may benefit and
expand their ranges.
Many arctic species are
likely to become
extinct.
Adaptation: Wildlife
and habitat
management to
provide mitigation
corridors or relocation
assistance; protect
vulnerable habitats
from further impact.
Mitigation might not be enough
26
TERMS TO KNOW:
Adaptation
Impact: 30 to 300
million people will be
affected at
temperature increases
of 2−4oC.
Adaptation: Relocation
of some coastal
communities may be
necessary; construct
protective barriers like
seawalls and restore
wetlands in coastal
areas to protect inland
areas.
Mitigation might not be enough
26
Offset CO2 production
Terrapass.com
Community awareness
350.org
PERSONAL CHOICES THAT HELP
26
UNDERSTANDING THE ISSUE
26
UNDERSTANDING THE ISSUE
www.ipcc.ch
26
ANALYZING THE SCIENCE
26
EVALUATING NEW INFORMATION
26
MAKING CINNECTIONS

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