Climate Change: An Inter-disciplinary Approach to Problem Solving��Past Climate: Ice Ages

Richard B. Rood

rbrood@umich.edu

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Winter 2021

Bubbles of gas trapped in layers of ice give a measure of temperature and carbon dioxide

350,000 years of Surface Temperature and Carbon Dioxide (CO₂)

at Vostok, Antarctica ice cores

• During this period, temperature and CO₂ are closely related to each other

This has been extended back to > 700,000 years

Ice Age Cycles: 800,000 Years

Bubbles of gas trapped in layers of ice give a measure of temperature and carbon dioxide

350,000 years of Surface Temperature and Carbon Dioxide (CO₂)

at Vostok, Antarctica ice cores

• During this period, temperature and CO₂ are closely related to each other

What are we worried about?

350,000 years of Surface Temperature and Carbon Dioxide (CO₂)

at Vostok, Antarctica ice cores

• Carbon dioxide is, because of our emissions, much higher than ever experienced by humankind.
• Temperature is expected to follow
• New regimes of climate behavior?
• Humans are adapted to current climate behavior.
• The change is expected to happen rapidly (10 -100 years, not 1000’s)

CO₂ 2010

CO₂ 2100

390 ppm

460 ppm

Cycles into the future?

350,000 years of Surface Temperature and Carbon Dioxide (CO₂)

at Vostok, Antarctica ice cores

• If the normal pattern were to continue, without additional carbon dioxide, what would we expect?

CO₂ 2005

CO₂ 2100

360 ppm

460 ppm

Global cooling?

Why do we think that our predictions today are more robust than these predictions from the 1970s?

1975 versus Today?

Some questions

• Can we establish cause and effect from these graphs?
• Does CO₂ increase always cause temperature increase?
• What is the role of water? Methane?
• The cycles would suggest an ice age is on the way. Is an ice age inevitable?
• How do we answer this question?
• What does the ice age information tell us about balance?
• What are the feedbacks?

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