ATM S 111, Global Warming: Understanding the Forecast

ATM S 111, Global Warming:
Understanding the Forecast
DAY 1: OCTOBER 1, 2015
About Me
 Professor: Dargan Frierson
 Home town: Wilmington, NC
 Southeastern North Carolina, on the coast
About Me
 Home town: Wilmington, NC
Wilmington, NC
Hurricane Fran, 1996
About Me
 Home town: Wilmington, NC
Wilmington, NC
Hurricane Floyd, 1999
About Me
 Home town: Wilmington, NC
Wilmington, NC
Hurricane Bertha, 1996
About Me
 Home town: Wilmington, NC
Wilmington, NC
Hurricane Bonnie, 1998
About Me
 Home town: Wilmington, NC
Wilmington, NC
Hurricane Diana, 1984
About Me
 Undergraduate: North Carolina State, Raleigh, NC
Raleigh, NC
Total precipitation from Hurricane Fran, 1996 (my freshman year)
After Grad School
 Grad school at Princeton (applied math)
 Postdoc (2 yrs) at University of Chicago
 Professor at UW starting 2007
 Research primarily on large-scale atmospheric
responses to global warming
 I love teaching!
Especially at the undergraduate and introductory level
I’ve taught Climate Dynamics, Fundamentals of Climate
Change, Modeling the Atmosphere, Atmospheric Motions,
Geophysical Fluid Dynamics, Atmospheric Waves and
Instabilities, etc
Active in creating YouTube videos about atmospheric science
with our outreach group
Teaching Assistants
Two TAs in this class
Lexie Goldberger 
Studies how fire emissions
impact atmospheric
 Isabel McCoy
Studies how low clouds impact the
radiative budget of the earth
Goals of the Class
 We’re going to learn about:
 The science behind global warming
 How to critically evaluate what you hear about climate and
global warming
 Related issues such as energy alternatives and international
agreements on climate
Class Outline
 Weeks 1-2: Overview and global warming science
 Weeks 3-5: Principles of climate and impacts of
climate change
Week 6: Climate records, long ago and recent past
Week 7: Climate modeling and future projections
Week 8: The debate & solutions
Week 9: Technological solutions
Week 10: Political solutions
Required Textbook
 The Thinking Person’s Guide to Climate Change by
Bob Henson
Me and Bob Henson at NCAR
Required Course Materials
 “Clickers” for in-class questions and activities
 Turning Technologies ResponseCard RF
 AwemoreUW has clickers for rent for $8 per quarter
 We’ll start clicker questions on
Tuesday, so have a clicker by then!
 Comprehensive final: 25%
 Quizzes (2): 30%
 Homework: 25%
 In-class activities: 20%
“Quiz” Sections
 Actually for discussion, review, and problem solving
 In class activities for points
 Go to your registered section only (there’s only room
for 30 students in some classrooms)
 Bring your laptop this week if you have one!
Course Webpage
Check it often! It’ll have all reading assignments, links
to the HW, slides from lectures, etc
 Online using canvas (link will be posted on the
class website once the first assignment is ready)
Also slides from quiz sections are on canvas
You’ll get a walkthrough of canvas during sections this week
 OK to discuss problems with classmates, but turn in
your own answers
Clicker Questions
 One point for each right answer or survey question
 Half a point for wrong answers
 Grading will be in two week blocks:
 I’ll set a goal every two weeks for the number of points you
need for full credit
 Get the target score to get full credit
 Use only your own clicker
Other Ground Rules
 Respect!
 This can be a politically charged topic: respect your neighbor’s
 No talking, texting, e-mail, etc
 We’ll take a 10 minute break each class period
 @DarganF
 I’ll occasionally tweet links to materials presented in class,
places to go for more info about the lectures, relevant news
articles, my thoughts about the topics covered, etc
 Useful for you? Maybe, maybe not…
 A basic summary of the science of global warming
 Reading assignment for the summary:
Henson pp. 3-26, “Climate Change: A Primer”
 FAQ about climate change
Also for next class:
Henson pp. 27-40, “The Greenhouse Effect”
The Atmosphere From Space
Weather versus Climate
 Weather varies from one day to the next
 Climate: averages of the weather over a longer period of
 Example:
You put on clothes for the weather…
Should I pack an umbrella?
You buy clothes for the climate…
Going where the climate suits my clothes – lyrics from Lonesome
Road Blues (traditional, e.g., Henry Whitter, 1924)
 Both weather and climate can be predicted with some
Weather vs. Climate
 Weather is like your mood…
 Climate is like your personality…
Weather vs Climate in Western N. America
 Weather is the individual storms
 Climate is the fact
that all of them hit
western WA!
Animation of cloud thickness
from a climate model
What Factors Influence Climate?
 Sunshine
 And relatedly, latitude
 Topography/mountains
 Proximity to oceans and large lakes
 Ocean currents
 Presence of trees/vegetation
 Etc.
The atmosphere from space…
90% of the mass of the atmosphere is within 16 km (10 miles)
of the surface
Proportionally, the atmosphere is half as thin as seams on a
It’s remarkably thin…
A thin atmosphere means we can change
atmospheric composition
We Modify the Composition of the Atmosphere
 Carbon dioxide (CO2) has been measured at Mauna
Loa, Hawaii since 1958
“Keeling curve”: first measured
by David Keeling in March ’58
Over 25% increase since the
first measurement
Human induced:
Due to fossil fuel burning
(90%) and deforestation (10%)
Let’s Look Way Back to 450,000 Years
 We’re at 400
ppm now
Natural variation over
Ice Age Cycles:
180-280 ppm
Current rate of increase
is 100-1000 times
faster than nature can
change CO2
Img src: Global Warming Art
CO2 is a Greenhouse Gas
 Greenhouse gases slow heat loss to space
 Has been known for a long time (J. Fourier in 1824)
This is why it’s
The Sun heats the Earth.
Greenhouse gases cause the Earth to be a lot
warmer than if there was no atmosphere:
58o F (32o C) warmer
The natural greenhouse effect
Joseph Fourier
The Earth is Warming
 More CO2 -> warmer atmosphere (eventually)
 Has it been getting warmer?
It’s warmed about
0.8o C (1.5o F) in
the last 130 years
1o F
0.5o F
Especially rapid
warming since the
13 out of the top
14 hottest years
on record were the
-0.5 F last 13 years
Warming has happened almost everywhere.
Northern high latitudes have warmed the most.
Land has warmed more than ocean.
Source: IPCC AR5
Isn’t there controversy about this data?
 No, we’re confident about the thermometer data
 There has been discussion about tree ring
reconstructions (known as the “hockey stick”):
1o F
This is less certain,
and only represents the
Northern Hemisphere
0o F anyway (gray area
indicates uncertainty)
-1o F
We’ll discuss this and
other controversies
more later…
-2o F
What Else is Happening?
 Arctic sea ice is melting 
 The ocean is gaining heat 
 Sea level is rising
20 cm = 8 inches
Also glaciers are melting, humidity is
increasing, species are shifting, etc
Glacier retreat
We don’t have to go far to
see the retreat of mountain
White Chuck glaci
North Cascades
What’s Predicted for the Future?
 A fundamental uncertainty is future human
Will we reduce emissions, or will we burn fossil fuels more and
more rapidly?
How quickly will developing countries get rich, and will they use
the same dirty fuels as we have?
Future Temperature Rise Predictions
 Uncertainty both in human behavior (colors) and
climate feedbacks (shaded area around)
Climate models are saying “you ain’t seen nothin yet”
6o F
4o F
2o F
0o F
Business as usual would
mean 3-5.5o C (5.5-10o F)
more warming
“Utopia”: 0.5-1.5o C
(0.9-2.7o F) increase
Controversy About All This?
 No doubt about these things:
 The greenhouse effect
 That CO2 and other greenhouse gases are increasing due to man
 That temperatures are rising
 Skeptics tend to argue for:
 “Negative feedbacks” that keep the temperature changes small
 Or that warming wouldn’t be such a bad thing
 Or about flaws in a particular study
 Be wary:
 Much of “the debate” (on both sides) is not very scientific
 Let’s sort out fact from fiction!
A Sampling of Future Topics
 “Paleoclimate”:
 Ice Ages and hot climates of the past like the Cretaceous
Ice sheet extent
Last Glacial Maximum
The Cretaceous Seaway
Volcanoes and Climate
 How the Earth cools after certain types of
Eruption of Mount Pinatubo in June 1991 and its effect on global temperatures
And Man-Made Volcanoes!
 “Geoengineering”: using technology to cool the Earth
 People are considering things like
 Putting volcanic-type particles into the stratosphere
 Space mirrors
 Cloud machines
 Fake trees
Right picture from Rolling Stone article “Can Dr. Evil Save the World?”
The Effect of Climate on Nature
 Cute animal pictures!!
Climate and the Rainforests
 The effect of burning tropical rainforests on climate
 And the effect of climate change on rainforests
Rainforests burning over
the Brazil-Bolivia border
Satellite photo from NASA
Locations of fires marked
by (enhanced) red dots
Winners and Losers
 Who will benefit…
New shipping lanes
• And who will it hurt the most?
 Floods in Yemen, October 2008
And Droughts…
 Lake Chad
Alternative Energies & Fuels
 Pros and cons of wind, solar, nuclear, ethanol, etc
Science and Policy
 The ozone problem
 This was solved by the most efficient interaction between
science and policy to date
Discovery of the ozone hole led to a ban on all CFCs
Why is global warming so much more difficult from a policy perspective?
Very Exciting Time for Climate Science!
 One of the strongest El Niño events in history is
 Hottest year in human history
 Paris meeting: Nov-Dec 2015
Many are optimistic about the world making big progress on
reducing emissions
Let’s Get Started!
 First topic: the science of global climate
 What are the key factors that determine the
temperature of Earth?