The Facts and Fiction of Climate Change Kim Cobb Paideia School April 15, 2008

Which of the following are scientific statements? 1)Slowing global warming costs too much money. 2) Hurricane Katrina was caused by global warming. 3) The Earth was warmer than today 60 million years ago.

Which of the following are scientific statements? 1)Slowing global warming costs too much money. 2) Hurricane Katrina was caused by global warming. 3) The Earth was warmer than today 60 million years ago.

What is CLIMATE? how the weather acts over many years What is WEATHER? temperature, rainfall, wind changes over days Some definitions

Why Study Climate? CLIMATE is our best guess at what temperature and rainfall patterns will be - next year - next ten years - next century CLIMATE is changing, and we need to prepare for the future - crops need enough water to grow - we need water to drink (but not too much) - ice is melting, sea level is rising (very slowly)

What is CO 2 (carbon dioxide)? - represents less than 1% of the atmospheric gases - animals breathe CO 2 out, plants “breathe” CO 2 in - burning fossil fuels (gasoline, oil) dumps CO 2 into the atmosphere - more atmospheric CO 2 warms the atmosphere

greenhouse gases in the atmosphere trap heat at the Earth’s surface and prevent it from escaping without greenhouse gases average temp of Earth would be -18ºC instead of 15ºC So the greenhouse effect is a good thing! we are increasing the greenhouse effect by adding CO2 to the atmosphere

The consequences of climate change in 100 years…. average global temperatures will rise by 2-14F sea level will rise by 7-22 inches rainfall patterns will change Why is there so much uncertainty in future climate?

One uncertainty comes from unknown future CO2 Will we join international plans to reduce CO2? Will we ignore the problem? What will other countries like China and India do? Decisions made NOW will effect your grandchildren!

Another uncertainty comes from imperfect climate models Over 20 models are used, because we don’t know which one is right.

Tools to study Paleoclimates -- “ancient” climates “the past is the key to understanding the present” Corals - oceanic, tropical - 100’s yrs long Sediments - along coastlines - 10,000’s yrs long - Ice Ages Tree Rings - continents -1000’s yrs long Ice Cores - North, South poles - 10,000’s yrs long - Ice Ages

Studying Climate with Corals What is a CORAL? a tiny animal in the shallow tropical ocean that lives colonially and grows a hard rock skeleton corals can live for hundreds of years

My Research: Studying Climate with Corals Goal: to compare past tropical Pacific climate with present-day climate Palmyra Island

How it works: 1)coral skeletons record temperature changes 2)we can count back 1000 years to read temperature

Corals provide long records of past climate that can be compared to present climate (is it different? how?) Science can be fun !

Global warming is very real, but the exact consequences are uncertain. Example: Driving in a car is dangerous, but you don’t know when you might have an accident. Do you wear a seatbelt? YES! We must begin to act to reduce global warming BEFORE we know the exact consequences.

The good news: humans are VERY smart! Three strategies to reduce CO2: 1)use less energy - drive less, drive smaller cars - conserve electricity 2) make “clean” energy - solar power, wind power, nuclear energy 3) take CO2 out of the sky (more difficult) - 50% CO2 + $$ cost - $$

What can YOU do? Bug your parents to buy flourescent light bulbs! When you starting driving, don’t drive an SUV. Save electricity wherever you can. Think about a job in science and engineering or politics, or education. Can you think of three things you can do to start saving the planet?

A climate scientist’s plea to the next generation: seek out information, ask questions, get the facts, and then VOTE distinguish the science of global warming from the politics/economics of global warming recognize uncertainties, but don’t be paralyzed by them [buy flourescent light bulbs, don’t drive SUV’s, eat your broccoli] THANK YOU Google ‘Kim Cobb’ for web-site

Studying Climate with Corals What is a CORAL? a tiny animal in the shallow tropical ocean that lives colonially and grows a hard rock skeleton corals can live for hundreds of years

My Research: Studying Climate with Corals Goal: to compare past tropical Pacific climate with present-day climate Palmyra Island

How it works: 1)coral skeletons record temperature changes 2)we can count back 1000 years to read temperature

Summary We need to understand more about how climate is changing. Corals provide long records of past climate that can be compared to present climate (is it different? how?) Science can be fun !