Natural Mechanisms of Climate Change

How do we know about past climates?

• Paleoclimatology- the study of the history of the earth’s climate

• Using: ice cores, tree rings, and lake bottom sediment

External Forces – beyond earth• Solar Energy- changes in 3 ways:• 1. Shape of earth’s orbit – sometimes circular,

sometimes elliptical

• 2. Changes in earth’s tilt – currently at 23.5 degrees– Varies from 22-25 degrees over 41,00 yr cycle– Smaller the tilt means less seasonal variation.

• 3. Changes in earth’s spin – it wobbles sometimes.

• Ocean, Atmosphere and Land Forces of Climate Change

Ocean Causes Changes• Change climates along the coasts theyu

flow

• Change in temp

• Change in the Great Ocean Conveyor

Volcanic Activity

• Releases SO2 which forms sulfic acid and reflects sunlight

• Releases huge amounts of ash and dust

-blocks the sun

• Short tem

Atmospheric Albedo

• The reflective property of the atmosphere (amount of sunlight atmosphere reflects)

• An ↑ in clouds means an ↑ in reflection

• A ↓ in clouds means a ↓ in reflection

• The more sunlight that reaches Earth the temp ↑

Surface Albedo

• Earth’s reflective capacity

• Includes land, snow, water, and ice

• Ice and snow reflect, land absorbs

• As ice and snow melt, less sunlight is reflected, more is absorbed, temp ↑

Asteroids and Meteoroids

• If huge ones impact Earth, large amounts of dust and debris in atmosphere

• May block out the sun

• Leading theory on what killed the dinosaurs

Plate tectonics

• Changes where glaciers can form

• Changes the flow of currents

• Changes the climates on different continents

• Redistributes the areas of absorption of solar radiation