The Climate SystemLecture 1

Ecological Climatology

Why does climate vary from place to place?

Why does climate vary from place to place?

Why does climate vary from place to place?

Why does climate vary from place to place?

Ocean Circulation

Why does climate vary from place to place?

Causes of Climate Change

Earth’s Orbital Characteristics

• Gradual changes in the tilt of Earth’s axis relative to its orbit around the sun at a cycle of 41,000 years

• Gradual changes in the eccentricity of Earth’s orbit around the sun occur at a cycle of 100,000 years

Earth’s Orbital Characteristics

• Changes in the timing of the Perihelion and Aphelion cause changes in the amount of solar radiation received on 22,000 year cycle

Earth’s Orbital Characteristics

Methane• Orbital monsoon theory: • more sun → more monsoon → more methane • less sun → less monsoon → less methane

Methane

• Agriculture originated independently in areas shown in black

Carbon Dioxide

Carbon Dioxide

• By 2,000 years ago, sophisticated forms of agriculture were practiced in naturally forested areas of China, India, southern Europe, and Mediterranean North Africa

Overdue Glaciation

A natural cooling trend in the Northern Hemisphere should have passed the threshold for initiated a new glaciation several thousand years ago

Overdue Glaciation

When greenhouse gases of human origin are removedFrom the atmosphere in a climate-model run…

Overdue Glaciation

Impacts of Disease of Climate