Climate Change

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Climate Change

• Bause/Kulman
• North Farmington High School

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Factors affecting climate

• 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

• from millions of years
• from thousands of years
• to even 100s to 10s of years.

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Global Average Temperature for the past 2000 years
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How do we know the climate has changed?

• Seafloor sediments
• near surface organisms die and their remains
  become part of the sediments.
• number/types of organisms change with changing
  climate
• Oxygen isotopes
• measures the ratio of O16 to O18 found in ice and
  sedimentary rock.
• O16 evaporates easier than O18. Because of this
  O16 is more often associated with precipitation.
  THUS becoming part of the glacial ice.
• O18 is left in the water. So, during ice ages,
  there is more O18 in the water. And visa-versa
• 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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CO2 2000 yrs ago to present
Methane 2000 yrs ago to present

• Carbon Dioxide and methane are two greenhouse
  gases. Methane is 30 times better at absorbing
  infrared radiation.

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Natural Causes of Climate Change (NOT caused by
human activity)

• Plate Tectonics
• Volcanic Activity
• Sunspot Activity
• Milankovitch Cycles

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Natural Cause of Climate Change- Plate 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 Change- Volcanic 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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Natural Cause of Climate Change- Sunspot 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 Change- Sunspot Activity

• Solar flares release LOTS of radiation.
• Sunspots/flares are associated with an INCREASE
  in solar radiation reaching the Earths
  atmosphere which can warm the Earth

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Natural Causes in Climate Change- Milankovitch
Cycles

• Earths tilt changes on a 26,000 year cycle
• Earths 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 Change- Milankovitch
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
• Farming
• Flatulence
• Fertilizing
• 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.
• Weve 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 Climate- Fertilizing Fossil
Fuels

• 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 Change- Storms
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Consequences of Global Warming- Storm 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 doesnt even make it to the ocean anymore.

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Consequences- Sea level rising

• As continental glaciers melt, water level will
  rise.
• Its 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.

• Red indicates areas that will likely be under
  water.

• NOTE this is not the real Statue of liberty