Transcript Climate Change

Climate Change
Bause/Kulman
North Farmington High School
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Factors affecting climate
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Atmosphere (the air)
Hydrosphere (the water)
Solid Earth (crust)
Biosphere (life)
Cryosphere (ice)
*** A change in any one of these systems
can cause a change in climate!
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Is the Earth warming?
Global average temperatures 18,000 yrs ago to present
• YES!!!
• For the past 20,000 years the Earth has been warming!
• Which is why the glaciers are not here today.
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From reconstructions of past
climates, climate has varied…
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from millions of years
from thousands of years
to even 100’s to 10’s of years.
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Global Average Temperature for the past 2000 years
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Land-based Surface Temperatures
over the past 250 years
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How do we know the climate has
changed?
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Seafloor sediments
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near surface organisms die and their remains become part of
the sediments.
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number/types of organisms change with changing climate
Oxygen isotopes
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measures the ratio of O16 to O18 found in ice and sedimentary
rock.
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O16 evaporates easier than O18. Because of this O16 is more
often associated with precipitation. THUS becoming part of the
glacial ice.
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O18 is left in the water. So, during ice ages, there is more O18 in
the water. And visa-versa
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certain crustaceans use CaCO3 (called calcite) to make their
shells. The Oxygen used is reflected in the shells. When the
organism die, their hard shells become part of the ocean
sediment.
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Carbon Dioxide and methane are two greenhouse gases.
Methane is 30 times better at absorbing infrared
radiation.
CO2 2000 yrs ago to present
Methane 2000 yrs ago to present
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Natural Causes of Climate Change
(NOT caused by human activity)
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Plate Tectonics
Volcanic Activity
Sunspot Activity
Milankovitch Cycles
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Natural Cause of Climate ChangePlate Tectonics
• Ice needs a land mass to collect on.
• If there are no land masses along the poles, and
thus more of them near the equator, typically
these are times of warming.
Currently there is no
land mass directly on
the North Pole, but close
enough with Greenland.
This allows ice to gather
and stick around.
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Natural Cause of Climate ChangeVolcanic Activity
• volcanoes release of
aerosols (tiny solids)
increase atmospheric
albedo and block
insolation (incoming
solar radiation).
• Ex. 1815 Mt. Tambora
“Year without a
Summer”. Snow in
June, frost in August.
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Volcanoes or Humans?
Mt. St. Helens
Mt. Pinatubo
Krakatoa
Mt. Tambora
The year without a summer
Where’s Dante’s Peak?
• The RED is a
simple fit (or best
fit) line.
• The dips you see
correspond to
LARGE volcanic
eruptions.
• Despite the ash
from the volcanic
eruptions, the
overall trend is
increasing.
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Natural Cause of Climate ChangeSunspot Activity
• Sunspots are dark blemishes on the
surface of the sun and are often
associated with large solar eruptions.
Sunspots
Solar flare
50 times the diameter of Earth
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Natural Cause of Climate ChangeSunspot Activity
• Solar flares release LOTS of radiation.
• Sunspots/flares are associated with an
INCREASE in solar radiation reaching the
Earth’s atmosphere which can warm the Earth
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Natural Causes in Climate ChangeMilankovitch Cycles
• Earth’s tilt changes on a 26,000 year cycle
• Earth’s orbit becomes very elliptical, back
to “circular” on a 100,000 year cycle.
• Major glaciations occur when they both
align.
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Natural Causes in Climate ChangeMilankovitch Cycles
• During circular orbits, Earth warms.
• During elliptical orbits, Earth cools.
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Human Impact of Climate
***Not just CO2***
• The FOUR “Fs”
1. Farming
2. Flatulence
3. Fertilizing
4. Fossil Fuels
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Human Impact of Climate- Farming
• Cutting down trees/vegetation for farming
– Farm land/dark soil has less albedo than forests.
• Stirring soil (tilling) releases naturally stored
CO2 in soil aggregates.
***We’ve been doing this for 1000s of years***
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Human Impact of Climate- Flatulence
• Methane (CH4) is produced from cattle,
and from swamps (including artificial
swamps used to grow rice). Also produced
in landfills.
• 20-30 times better at absorbing terrestrial
radiation than CO2
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Human Impact of ClimateFertilizing & Fossil Fuels
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FERTILZING: Nitrous Oxide (N2O) is
produced from nitrogen fertilizers
• FOSSIL FUELS: CO2 AND N2O are
produced during the combustion of fossil
fuels.
*** N2O is also a greenhouse gas and is 300
times better at absorbing infrared
radiation than CO2***
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Consequences of Climate Change
• The IPCC (Intergovernmental Panel on
Climate Change) states, "Taken as a
whole, the range of published evidence
indicates that the net damage costs of
climate change are likely to be significant
and to increase over time."
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Consequences of Climate ChangeStorms
Hurricane Sandy 2012
$65,000,000,000
2012 Midwest/Plains Drought
$35,000,000,000
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2014 Detroit Flood
• Estimated cost of $1.1 billion
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Consequences of Global WarmingStorm frequency
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Water resources and agriculture
• Changes in water distribution. SW US, a
2oC change in temp could result in 50%
less precipitation.
• Demands from the Colorado river now do
not meet the needs.
– it doesn’t even make it to the ocean anymore.
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Consequences- Sea level rising
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As continental glaciers melt, water level will rise.
It’s not just the glaciers melting! If temps go up, then
the temps of oceans go up. If you increase heat, you
increase the VOLUME (space) the water takes up.
I hope Mickey knows how to SWIM!!!
• Red indicates areas that will likely
be under water.
• NOTE: this is not the real Statue
of liberty
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