How Humans Impact Earth’s Radiation Balance
Global Warming
Ozone Layer Destruction
Greenhouse Gases (like carbon dioxide) are like a rechargeable battery for heat
Global Warming: A Preview in Classroom Resource Movies
What are greenhouse gases?
Always ask in climatic change: What has happened in the past?
Always ask in climatic change: What has happened in the past?
Eocene Warmth
Eocene Arctic was ice free …
Ice Age Fluctuations: Never above 300 ppm (parts per million)
Classroom Resources
CO2 helped warm Ice Age Earth
Warming continued as civilizations flourished in the Holocene (last
10,000 years), then cooled with the sun in the Little Ice Age
Warm Periods in the Holocene were wetter in Monsoon Asia
Big Questions over Trends and whether natural or human caused
Classroom Resource:Why is theStarting point 100 years ago? Industrial revolution? or After Little Ice Age?
Graphs starting point
Change from
Little Ice Age and
lower Solar
Output?
Story is complicated by type of radiation
1365.0
1365.5
1366.0
1366.5
1367.0
1367.5
1368.0
1368.5
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Irra
dia
nc
e
TotalTotal UltravioletUltraviolet VisibleVisible InfraredInfrared0.00.0
0.10.1
0.20.2
0.30.3
0.40.4
0.50.5
0.60.6
0.70.7
Wild cards: organic & inorganic aerosols
(dust, pollution) cooling
influence
So what happens if coal pollution is reduced?
Will we get complacent in the next century, causing massive trouble in 50 years?
Predictions Vary
How much of the warming is due to “urban heat island”?
Where are the thermometers?
Rural Kitt Peak
Urban growthPhoenix
Always the problem: sorting out cause (GHG, Solar, Urban) from
the effect (warming in some places)
Satellite Record: least bias• Red line (used to be no evidence of
warming)
• Blue & Green (lower and middle troposphere) – warming is evident, but is it natural or us?
Potential Impacts: There will be Winners and Losers, just VERY hard to predict with models (good to try, just nobody really believes them)
Winner: Plant Productivity
Plants Plants love love
elevated elevated COCO22
Winner: longer northern growing seasons for wheat
Winner: India avoids drought from Cool Earth
Long Record
Warm
Earth
Favors
Wetter
Asian
Monsoon
Winner: More
Tropical Rain
Loser: the Arctic (Classroom Resource Movie)
Loser: close to shore
Compilation and Analysis in Science – October 2005Read scale:centimeters
So why show Florida under water?
Real Evidence: Not sure if big ice sheets are melting
Stakes are high for
low-lying places
Agriculture: Predictions of Losers in Lower Latitudes
Other possible effects (written by those favoring a need for quick action)
““... climate models give no consistent indication ... climate models give no consistent indication whether tropical storms will increase or decrease in whether tropical storms will increase or decrease in frequency or intensity as climate changes; neither frequency or intensity as climate changes; neither is there any evidence that this has occurred over is there any evidence that this has occurred over
the past few decades.”the past few decades.” IPCC, IPCC, 1990 (p. xxv)1990 (p. xxv)
““Changes globally in tropical and extra-tropical storm Changes globally in tropical and extra-tropical storm intensity and frequency are dominated by inter-intensity and frequency are dominated by inter-decadal and multi-decadal variations, with no decadal and multi-decadal variations, with no
significant trends evident over the 20significant trends evident over the 20thth century.” century.”IPCC,IPCC, 2001, p. 5 2001, p. 5
More Hurricanes?
“Multi-decadal variability and the quality of the tropical cyclone records prior to routine satellite observations in about 1970 complicate the detection of long-term trends in tropical cyclone activity. There is no clear trend in the
annual numbers of tropical cyclones.”IPCC,IPCC, 2007, p. 6 2007, p. 6
““Overall, there is no evidence Overall, there is no evidence that extreme weather events, that extreme weather events,
or climate variability, has or climate variability, has increased in a global sense, increased in a global sense,
through the 20through the 20thth century, century, although data and analyses are although data and analyses are poor and not poor and not comprehensive.”.”
Houghton et al., 1996,Houghton et al., 1996, IPCC, IPCC, p. 173p. 173
"We are becoming more "We are becoming more vulnerable to natural disasters vulnerable to natural disasters
because of trends of our because of trends of our society rather than those of society rather than those of
nature. In other words, we are nature. In other words, we are placing more property in placing more property in
harm's way."harm's way."
van der Vink et al., 1998,van der Vink et al., 1998, EOS, EOS, p. 537p. 537
Extreme chance:Reduce
Gulf Stream
Not Not tomorrow!tomorrow!
What to do?
• Set policies by governments?• Make personal choices (my choice is to
hang laundry on the line, ride my bike, use evaporative cooler) save money, while reducing my contribution to GHG
• Ask China and other societies not to industrialize? China generates more GHG than USA!
• Great setting for classroom lessons
Classroom Resource
Extreme Solution
It all comes
down to
Keeping
Earth’s
radiation in
balance
Time Special Report
Understand Understand difference difference
between science between science & media spin& media spin
Human Impact on Radiation BalanceIgnored by the Media: Ozone Crisis
Why media ignores? Fear of chemistry?
Or not understand completely different problems?
Positive Feedback Started Buildup
Ozone Still Made in Lower
Latitudes
Classroom Resource
First question: has Earth’s biosphere survived past reduction in ozone?
Classroom Resource
Fear is damage by UV radiation
What’s the crisis? We add more chlorine to the stratosphere
Classroom Resources
Polar Stratospheric Clouds Key
Classroom Resource
Creates Antarctic Ozone Hole
Classroom Resources
Keeps getting worse
Arctic less problematic because warmer (less polar stratospheric clouds) – except in cold years
We add other ozone-destroying agents
Politics & predictions ignore legal and illegal cheating
Imagery seen in this presentation is courtesy of Ron Dorn and other ASU colleagues, students and colleagues in other academic departments, individual illustrations in scholarly journals such as Science and Nature, scholarly societies such as the Association of American Geographers, city,state governments, other countries government websites and U.S. government agencies such as NASA, USGS, NRCS, Library of Congress, U.S. Fish and Wildlife Service USAID and NOAA.