How we know what we know about climate change

Nathan Hobbs Becca Hatheway

Lisa Gardiner

HOW DO WE KNOW WHAT WE KNOW?

USING CLIMATE SCIENCE AS A VEHICLE TO INCREASE STUDENT CONFIDENCE IN SCIENTIFIC DATA AND

INTERPRETATION

Doran 2009

WHAT PERCENTAGE OF CLIMATE SCIENTISTS AGREE THAT THE EARTH IS WARMING AND HUMANS ARE THE CAUSE?

WHAT PERCENTAGE OF THE U.S. PUBLIC AGREE THAT THE EARTH IS WARMING AND HUMANS ARE THE CAUSE?

Earth is warming.

Humans have been the main cause of warming over the past 60 years (95-100% prob).

The amounts of CO2, methane, and nitrous oxide are higher than they ’ve been for 800,000 years.

If we reduce emissions we can limit future warming, however some warming is inevitable.

WHAT DO WE KNOW?

The Intergovernmental Panel on Climate Change 1000s of climate scientists from around the world and representatives from

world nations, an effort coordinated by the United Nations.

IPCC 5 th Assessment Report – The Physical Science Basis

Released September 2013

Includes the current state of understanding of climate and climate change (and how we know what we know about climate).

SAYS WHO?

WORKSHOP ACTIVITIES

Ways of knowing about climate Classroom Activities

Climate models Model Resolution

Paleoclimate proxies Oxygen Isotopes

Instrumental record Matching Data and Meaning

What is a climate model?

Global climate models (GCMs) use mathematical equations to describe the behavior of factors of the Earth system that impact climate

Climate scientist perspective on confidence in climate models

ABOUT CLIMATE MODELING

Scenarios of Future Carbon Dioxide Global Emissions and Concentrations

Nakićenović, N. and R. Swart (eds.), 2000: Appendix VII: Data tables. In: Special Report on Emissions Scenarios

MODEL RESOLUTION

Step 1: Tape gr id paper to top of container ( lower or higher resolut ion gr ids).

Step 2: Poke skewers through paper at the intersections.

Step 3: Try to determine the shape of the legos in the bottom of the box based on the height of the skewers. Mark this shape on blank gr id paper.

Step 4: Compare shapes between high and low resolut ion gr ids.

Step 5: After you’re done… check the bottom of the box to see the shape of the legos!

MODEL RESOLUTION ACTIVITY

PALEOCLIMATOLOGY: AN INVESTIGATION

What is a proxy?

Resolution vs. Span

Examples of proxies

Ice cores

Tree rings

Pollen

Speleothems

Coral

Historical documents

The Water Cycle, Oxygen-18, and Ice Cores

INDIRECT CLUES ABOUT PAST CLIMATES ARE KNOWN AS PALEOCLIMATE PROXIES, OR

PROXY RECORDS

Just as Sherlock Holmes might infer the height, weight

and other telltale features of a suspect from a series of

footprints, paleoclimatologists infer the climatic

conditions of the past from tree rings, ice cores, layers

of ocean sediments, and similar proxy evidence.

(Randy Russell, Spark: UCAR Science Education)

TWO FACTORS ARE USED TO DESCRIBE TYPES OF PALEOCLIMATE PROXY DATA

Span – how far back in time the record allows us to peer.

Tree ring records span the most recent few thousands of years.

Ice core records go back as much as hundreds of thousands of years.

Fossils can be up to hundreds of millions of years old.

Resolution – the level of detail of a proxy record.

Tree ring data can have an annual resolution.

Ocean sediments, on the other hand, often have resolutions on the order of a century because sediments are mixed by currents and burrowing marine life, blending short-term trends.

SOME TYPES OF PROXIES

Speleothems : the chemistry of l imestone deposits provide clues to past climate

Tree rings : the thickness of rings is an indicator of growing season conditions.

Coral : chemistry of skeletal layers provides clues to past climate.

Pollen: the variety of plant species (identified from pollen), combined with information about the climate where those species typically thrive, provides clues to past climate

And also …

ICE CORES

http://michigantoday.umich.edu/2009/11/vostok-graph.jpg

VIDEO: ICE CORE SECRETS COULD REVEAL ANSWERS TO GLOBAL WARMING

VIDEO: DEMO OF O-16 AND O-18 PHYSICAL MODEL

PC1 VS. TEMPERATURE GREENLAND 1829-1970

R² = 0.497

-8.000

-6.000

-4.000

-2.000

0.000

2.000

4.000

6.000

8.000

-16 -14 -12 -10 -8 -6 -4 -2 0 2

PC

1

Average Temperature ( C)

PC1 valuesLinear (PC1 values)

On your table

Graphs of data from the instrumental record of climate and global change from the IPCC 5th Assessment Report.

Statements that are supported by the graphed data

Statements that are not supported by graphed data

Match each graph with the statement that it supports.

(Note: This activity is a prototype and we’d like your feedback.)

MATCHING DATA AND MEANING

ADDITIONAL RESOURCES

Learn more about climate science at spark.ucar.edu

For workshop resources: spark.ucar.edu/workshops

Becca Hatheway – hatheway@ucar.edu

Lisa Gardiner – lisagard@ucar.edu

Thank you for coming!

MORE SPARK WORKSHOPS

Cooking Up Weather in the Primary Classroom

Friday, 8-9am Room MHB-2A

Computer Games, Simulations, & Virtual Labs

Saturday, 11-12pm, Room MHB-4B

Weather Headlines

Saturday, 11-12pm, Room MHB-2B

CLIMATE CHANGE: A TEACHING PERSPECTIVE

Jeff KiehlSenior Scientist

National Center for Atmospheric Research

Thursday, 3:30-4:30Convention Center Room 103/105

Overview of the findings of the recent Fifth Assessment Report of the Intergovernmental Panel on Climate Change and discussion of the basic

science.