Paleoclimatic Data

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.

What is paleoclimatic data?

“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.

Why use paleoclimatic data?

Coral Ocean and lakes sediments

Fossilized pollenFossilized plantsFossilized shells

Tree Rings/Fire history Ice Cores Cave deposits Loess and Eolian

Types of paleoclimatic data

Ocean and lakes sedimentsFossilized plantsFossilized shellsFossilized pollen

Ice Cores

Most of the following materials come from the National Climatic Data Center: http://www.ncdc.noaa.gov/

Types of paleoclimatic data

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. 

Ocean and lake sediments

Algal alkenones: “Natural thermometers.”

http://icestories.exploratorium.edu/dispatches/alkenones-natural-thermometers/

Alkenones

Shell prevalence and composition tell us about chemical composition of the atmosphere and ocean as well as temperature.

Shells

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. 

Pollen

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. 

Ice Cores

http://www.youtube.com/watch?v=oHzADl-XID8

Ice cores: CO2, temps, & dust

Ice cores: CO2, CH4, & temps

What the story saysRuling out cosmic and geological activity.

Space dust Solar stuff Cosmic rays Volcanoes Continental drift What’s left?

Accounting for…

Ocean and lake sediments and ice cores

Proxy data that contains information on what?

Paleoclimatic data

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.

1. Space dust

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.

2. Solar output

El Niño and La Niña 

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.

Solar output and El Niño and La Niña

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?

3. Cosmic rays & solar wind

Cosmic rays and the magnetosphere

Solar wind strikes the Earth’s magnetic field

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 beryllium10 and magnetic alignments in lava flows.

4. Volcanoes

http://www.youtube.com/watch?v=C6_PIuIBUX8

Mount PinatuboPhilippines, 1991

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.

5. Continental drift

Sequence and global location of continental plates over previous 200 million years.

Continental drift occurs very slowly – inches per year.

Topography and arrangement matter.

But change is so slow it produces a negligible effect.

If not… Space dust Solar output Cosmic rays Volcanoes Continental drift

…what do we have to explain global warming?

CO2 and other greenhouse gases.

What’s left?