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• I have narrated many of the slides in the notes
section of this powerpoint. Please feel free to
use this information for educational purposes.
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Motivation: Why talk about this?
• This issue is not going away.
• Understanding the science helps us
realize what role we play in the solutions
to the issue.
Understanding your Audience
What do Adult Americans Think?
Proportion of the U.S. Adult Population in 2009 …
Random sample size n=2,129 people
For full report go to: http://www.americanprogress.org/issues/2009/05/6americas.html
Understanding your Audience
What do Climate Scientists Think?
Are humans responsible for observed warming?
What factors have the effect of
changing the Earth’s climate?
•
•
•
•
Land
Ocean
Sun-Earth
Atmosphere
What can change climate?
Changes in Land and Ocean
Circulation
The Milankovitch Cycle
Precession
26,000 years
Eccentricity
100,000-413,000 years
Tilt
41,000 years
The Milankovitch cycle, which has
caused ice ages and warm periods in
the past, is not causing the current
changes we observe.
What can change Earth’s Climate?
The Sun-Earth relationship
1750-1950: .2°F of warming
occurred due to 1% increase in
solar output during this period
1950-1970: slightly less output from
the sun, led to slight cooling
Energy coming from the Sun (1979-2007)
(measured at the top of the Earth’s Atmosphere)
Amount of sunlight
(Watts/meter2)
Monthly solar data
Average solar data
1980 1982 1984 1986 1988
1990 1992 1994 1996 1998 2000 2002 2004 2006
Source: NOAA
Data Show:
• Solar output approximately steady
• Sunlight is not causing the current climate change
What can change Earth’s Climate?
What can change Earth’s Climate?
Greenhouse Gases
What can change climate?
Greenhouse gases main factors
• Amount and rate
of emissions
released
• Effectiveness of
heat trapping
• Residence time in
the atmosphere
What can change climate?
Human caused (anthropogenic) greenhouse gases
Why focus on
CO2?
Amount of CO2
in the
atmospherehighest in
800,000 years
Historical rate:
30 ppm/1000
years
Current Rate:
30 ppm/last 17
years
What data do climate scientists use?
ground
observations
satellite
observations
balloon
data
continental
ice sheet
retreat
polar ice cap
retreat
mtn. glacier
retreat
sea surface
temps
permafrost
melt
ice cores
boreholes
coral reef
cores
cave data
tree rings
Warming
ocean
sediment
cores
biological
data
Rob Gillies slide modified, puzzle images from COMET
How do we know?
How do we know?
The data …
2008
1988 2000
Looking at the graph, what can you conclude about 2008 temperatures?
a)
2008 was the coolest year since 2000
b)
2008 was warmer than any year before 1988
c)
Global warming has ended, global cooling is occurring
d)
Temperatures in 2008 are consistent with global warming
e)
Two years of temperature data are enough to make statements about
global warming
Looking at the graph, what can you conclude about 2008 temperatures?
a)
2008 was the coolest year since 2000
b)
2008 was warmer than any year before 1988
c)
Global warming has ended, global cooling is occurring
d)
Temperatures in 2008 are consistent with global warming
e)
Two years of temperature data are enough to make statements about
global warming
Global average temperature
changes in 2008
Temperature differences
• Temperatures
around the
globe are not
uniform
• One area does
not give us the
whole picture
• One time does
not give us the
whole picture
Image Courtesy: Dr. David Chapman
Temperature Difference (°C)
compared to the year 2000
Why should we care?
• Only a few degrees means:
– National Security Threatened
– Health Impacts
– Negative Effects on Economics
– Hotter Summers/Warmer Winters
– Drought and Floods
– Sea-Level Rise
– Extreme Weather
– Ocean Ecosystems Stressed
– Regional Impacts
Why should we care?
Only a few degrees?
• Last Ice Age: 7-13°F
cooler
125,000 years ago: 1°F
warmer, sea levels were
20ft higher
Key Impacts as a function of Increasing Global Average Temperature Change
0°F
Global mean annual temperature change relative to 1980-1999
1.8°F
3.6°F
5.4°F
7.2°F
9°F
Increased water availability in moist tropics and high latitudes
Water
Decreased water availability and increasing drought in mid-latitudes and semi-arid low latitudes
Hundreds of millions of people exposed to increased water stress
Up to 30% of species at increasing risk of extinction
Increasing wildfire risk
Ecosystems
Food
Coasts
Health
Energy
Security/
Independence
Increased coral bleaching Most corals bleached
Increasing species range shifts
Significant extinctions
around the globe
Widespread coral mortality
Complex, localized negative impacts on subsistence farmers and fishers
Tendencies for cereal productivity
Productivity of all cereals decreases at
to decrease in low latitudes and
low latitudes and in some other
increase at mid-to high latitudes
regions productivity decreases
Increased damage from floods and storms
About 30% of global
coastal wetlands lost
Millions more people could
experience coastal flooding each year
Increasing burden from malnutrition, diarrheal, cardio-respiratory and infectious diseases
Increased morbidity and mortality from heat waves, floods, and droughts
Changed distribution of some disease vectors
Substantial burden on health services
Decreased water availability and increasing drought in mid-latitudes and semi-arid low latitudes
Increased damage from floods and storms
Increasing fire risk
Increased coastal flooding
Up to 30% of species at increasing risk of extinction
Significant extinctions
Figure Modified from the IPCC Report SPM.2. Impacts will vary by extent of adaptation, rate of temperature change, and
socio-economic pathway.
Warming by 2090-2099 relative to 1980-1999 for non-mitigation scenarios (Modified figure: SPM7 IPCC Report 2007)
2×CO2
stabilization
2.5×CO2
3×CO2
0°F
Water
1.8°F
1.8°F
3.6°F
5.4°F
Increased water availability in moist tropics and high latitudes
Up to 9.72°F
7.2°F
9°F
Decreased water availability and increasing drought in mid-latitudes and semi-arid low latitudes
Hundreds of millions of people exposed to increased water stress
Up to 30% of species at increasing risk of extinction
Increasing wildfire risk
Ecosystems
Food
Coasts
Health
Energy
Security/
Independence
Increased coral bleaching Most corals bleached
Increasing species range shifts
Significant extinctions
around the globe
Widespread coral mortality
Complex, localized negative impacts on subsistence farmers and fishers
Tendencies for cereal productivity
Productivity of all cereals decreases at
to decrease in low latitudes and
low latitudes and in some other
increase at mid-to high latitudes
regions productivity decreases
Increased damage from floods and storms
About 30% of global
coastal wetlands lost
Millions more people could
experience coastal flooding each year
Increasing burden from malnutrition, diarrheal, cardio-respiratory and infectious diseases
Increased morbidity and mortality from heat waves, floods, and droughts
Changed distribution of some disease vectors
Substantial burden on health services
Decreased water availability and increasing drought in mid-latitudes and semi-arid low latitudes
Increased damage from floods and storms
Increasing fire risk
Increased coastal flooding
Up to 30% of species at increasing risk of extinction
Significant extinctions
Why should we care?
Your bills
• Heating and Cooling
– $$$ Hotter summers
– $ Warmer Winters
• Water Bills
– $$$ Drought and
Floods
• Cost of food
– $$$ Sea Level Rise
– $$$ Crop failures
Why should we care?
Our Bills
• $$$ Extreme Weather
• $$$ National Security
• $$$ Tourism
Why should we care?
Crops and Climate
• USDA predicts faster growth in grain/oil
seed crops, but more prone to failure if
precipitation decreases.
Why should we care?
Crops and climate
• Earlier plant growth increases vulnerability
to spring cold spells
• April 2007 frost cost: $ 2 Billion in
agricultural losses
Why should we care?
Food Supply
hy should we care?
Climate Change and National
Security
Why should we care?
Human health-heat waves
more frequent and intense
During heat waves death rate increases by 6%
Why should we care?
Good news in the winter
• Warmer winters – less flu
Why should we care?
Milder temperatures = expanded
range for many disease carriers
Dengue hemorrhagiic fever first
appeared in U.S.: 2005 – tropical
borne disease
Experts worry that malaria could
reappear
Why should we care?
Air Pollution Worsens
Higher humidity
and warmer
temperatures leads
to more ozone and
particulate matter
forming and lasting
longer
Why should we care?
Air Pollution Worsens
• 1,000 more airpollution-related
deaths per year for
every 1.8°F
increase.
Western US Climate Change
• Most of the western US is
warming faster than the
global average
• Other climate trends across
most of the Western US in
the past 50 years include
– Longer frost-free growing
season
– Earlier and warmer spring
– Earlier flower blooms and leaf
out for several plant species
– Earlier spring snowmelt and
runoff
– Greater fraction of spring
precipitation falling as rain
instead of snow
Utah Climate Change
Utah Temperature (°F) 1895-2006
52
50
49
48
47
46
• There is no clear linkage between recent global
warming and precipitation within the basin of the
Great Salt Lake
2005
1995
1985
1975
1965
1955
1945
1935
• Snow surveys show no
clear long-term (80 year) trend in
mountain snowpack
1925
1915
1895
45
Line: 10 year running mean
Source: National Climatic Data Center
1905
• Last decade was 2°F
warmer than the 100
year average
51
Projected Temperature Change
• Greater warming
– In the Arctic
– Over land than ocean
– In winter than summer
• It is likely that Utah will warm more than the
global average
• Projected warming for Utah (2.5xCO2 scenario)
is 8°F by 2100
– Comparable to the present difference in annual mean
temperature between Park City (44°F) and Salt Lake
City (52°F)
Projected Precipitation Changes
• Less confidence in
precipitation
• Mid and high
latitudes wetter
• Most of subtropics drier
• Utah in the transition zone
projections
Utah Snowpack and Runoff
Decline in Utah’s mountain snowpack
and associated changes to spring
runoff
• Expected trends
– Reduced natural snowpack and snowfall
for the winter recreation industry in the
early and late winter
– Earlier and less intense spring runoff for
reservoir recharge
– Increased demand for agricultural and
residential irrigation
– Warming of lakes and rivers with impacts
such as increased algal abundance and
upstream shifts of fish habitat
Utah Water Supplies and Drought
• It is more likely than not that water
supplies in Utah and the Colorado
River Basin will decline during the
21st century
– More definitive projections not possible
at the present time
• The threat of severe and prolonged
drought far worse than observed in
the 20th century is real and ongoing
– Megadroughts have occurred in the past
Utah Agriculture
• Based solely on climate
change, per-acre crop yields
in Utah will likely increase on
irrigated fields provided
– Water remains available for
irrigation
– Temperatures do not increase
beyond crop tolerance levels
http://www.uacd.org/districts/north_cache/programs/programs.htm
• Pasture yields and livestock forage will likely
decline on non-irrigated fields
Other Utah Impacts
• Great Salt Lake: Declines in
mountain snowpack will likely
lead to lower average lake levels
and increased average salinity
unless average winter
precipitation increases
dramatically
• Human Health: Increased
ground-level ozone
concentrations and associated
cardio-respiratory disease if nonclimatic factors (e.g., emissions)
do not change
• Wildfire: In isolation, expected
climate change is likely to
contribute to drier conditions and
increased wildfire intensity
• http://www.cbsnews.com/stories/
2007/10/18/60minutes/main3380
Other Global Climate Trends
• Mean sea level rose 7 inches in the
20th century
• Shrinkage of mountain glaciers, ice
caps, and the Greenland ice sheet
responsible for 35-40% of the rise
since 1993
• Little or no long term trend in the
average number of tropical cyclones
per year
• Increasing financial losses from
hurricanes due to the ever-growing
concentration of population and
development in coastal regions