Climate Change and Earth Mommy, what were glaciers like?

Goals The Earth’s unique atmosphere? How does what we know about natural climate change relate to what humans can do?

Why is Earth so Different? Why do we have oceans of water? Why do we have so little carbon dioxide? Why do we have so much O2 and N2?

Compared to Venus Temperature just right. Water vapor could rain. Liquid oceans didn’t completely evaporate. CO2 could dissolve in oceans. 60x CO2 dissolved in oceans as atmosphere. 170,000x CO2 in carbonate rocks as atmosphere.

Goldilocks Planet Delicate balance: Earth is just right. No oceans without greenhouse gasses. Without oceans too many greenhouse gasses. Without oceans no life. Without life, no ozone. No ozone, no life. How does Earth maintain this balance?

Carbon Cycle Tectonics are crucial!

Nature’s Thermostat Carbon Cycle has negative feedback. Increasing temperatures lead to feedback that decreases temperatures, etc. Positive and negative feedbacks have nothing to do with desirability of outcome.

Too Cool Less Rain Less CO2 dissolves in oceans. More CO2 builds up in atmosphere Increased greenhouse Heats Up.

Too Warm More Rain More CO2 dissolves in oceans. Less CO2 builds up in atmosphere Decreased greenhouse Cool Down.

Ice Ages and Cycles

Cycles

Human Input Affecting CO2 cycle. Moving C from ground to air at increased rate. No increase in rate of C from air to ground.

Mars Today

Positive Feedback Fossil Fuels – Increase CO2 to atmosphere. Deforestation – decrease CO2 from atmosphere Increase CO2 – Increase greenhouse effect Increase temp – Melting glaciers, ice sheets, polar caps Less ice – lower planetary albedo Lower albedo – Earth absorbs more light More absorption – Increasing surface temperatures.