2. Past climate and environmental data is derived from
natural sources that inform us about Earth’s climate
thousands to millions of years ago.
Proxy data is data that stands in for instrumental
records from weather stations, balloons, and satellites.
Paleoclimatic data is therefore proxy data.
3. “History really does matter – if something
happened in the past, it must have been
possible, it should be understood, and it can
be used to test our understanding.”
If humans are changing the climate, we
should be able to rule out other things that
caused the climate to change before.
4. Coral
Ocean and lakes sediments
Fossilized pollen
Fossilized plants
Fossilized shells
Tree Rings/Fire history
Ice Cores
Cave deposits
Loess and Eolian
5. Ocean and lakes sediments
Fossilized plants
Fossilized shells
Fossilized pollen
Ice Cores
Most of the following materials come from the
National Climatic Data Center:
http://www.ncdc.noaa.gov/
6. Between 6 and 11 billion metric tons of sediment
accumulate in the ocean and lake basins each year.
Scientists drill cores of sediment from the basin floors.
Ocean and lake sediments consist of materials that were
produced in the lake/ocean or that washed in from nearby
land. These materials (preserved tiny fossils and chemicals
in the sediments) can be used to interpret past climate.
8. Shell prevalence and composition tell us
about chemical composition of the
atmosphere and ocean as well as
temperature.
9. Each species and genus of plants produces
pollen grains which have a distinct shape.
These shapes can be used to identify the type
of plant from which they came. Inferences can
then be made about the climate based on the
types of plants found in each layer.
10. Located high in
mountains and deep in
polar ice caps, ice has
accumulated from
snowfall over many
centuries. Scientists
drill through the deep
ice to collect ice cores.
These cores contain
dust, air bubbles, or
isotopes of
oxygen, that can be
used to interpret the
past climate of that
area.
http://www.youtube.com/watch?v=oH
zADl-XID8
14. Space dust
Solar stuff
Cosmic rays
Volcanoes
Continental drift
What’s left?
15. Ocean and lake sediments and ice cores
Proxy data that contains information on what?
16. Meteorite, asteroid, and comet impacts.
~65 m.y.a. an asteroid 6 miles wide hit the
Yucatan peninsula blasting a crater 110 miles
wide and blanketing the Earth with an ash
cloud.
17. The sun changes little over short time scales
accounting.
May slightly affect El Niño and La Niña
patterns in the Pacific.
El Niño is characterized by unusually warm
temperatures and La Niña by unusually cool
temperatures in the equatorial Pacific.
18.
19. While El Niño and La Niña can have warming
and cooling impacts at the equator of a
couple of degrees Celsius, current science
estimates the sun’s influence on these is a
few tenths of a degree Fahrenheit.
20. Rays from deep space and solar wind interact
with Earth’s atmosphere.
This radiation’s intensity varies.
It interacts with the Earth’s magnetic field.
How?
21. Solar wind ionizes
particles in the
atmosphere.
More solar wind ionizes
more particles.
Earth’s magnetic field
shields the atmosphere
and surface from solar
wind. The stronger the
magnetic field, the less
solar wind, the less
ionized the atmosphere.
The interactions are
traceable through
magnetic alignments in
Solar wind strikes the beryllium10 and magnetic
Earth’s magnetic field alignments in lava flows.
22. Volcanic eruptions
release CO2 & sulfuric
acid H2SO4
Large eruptions like
Mt. Pinatubo cool the
globe a few tenths of a
degree for a year or
two.
http://www.youtube.com Mount Pinatubo
/watch?v=C6_PIuIBUX8 Philippines, 1991
23. Continental drift
occurs very slowly –
inches per year.
Topography and
arrangement matter.
But change is so slow it
produces a negligible
effect.
Sequence and global location of continental plates
over previous 200 million years.
24. If not…
Space dust
Solar output
Cosmic rays
Volcanoes
Continental drift
…what do we have to explain global warming?
CO2 and other greenhouse gases.
