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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 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?

• 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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Volcanoes or Humans? • 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.

Mt. P

inatubo

Mt. St. Helens

Krakatoa

Mt. TamboraThe year without a summer

Where’s Dante’s Peak?

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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.

Solar flare50 times the diameter of Earth

Sunspots

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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 Earth’s atmosphere which can warm the Earth

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Natural Causes in Climate Change- Milankovitch 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 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”

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 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

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 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 doesn’t even make it to the ocean anymore.

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Consequences- Sea level rising• 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.

• Red indicates areas that will likely be under water.

• NOTE: this is not the real Statue of liberty

I hope Mickey knows how to SWIM!!!