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Using this powerpoint
• I have narrated many of the slides in the notes section of this powerpoint. Please feel free to use this information for educational purposes.
• Useful websites:• www.weatheroutreach.org• https://www.meted.ucar.edu/loginForm.php?
urlPath=broadcastmet/climate&go_back_to=http%253A%252F%252Fwww.meted.ucar.edu%252Fbroadcastmet%252Fclimate%252Fcontent%252Fsec06_01b.htm#
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.
Proportion of the U.S. Adult Population in 2009 …
What do Adult Americans Think?
For full report go to: http://www.americanprogress.org/issues/2009/05/6americas.html
Random sample size n=2,129 people
Understanding your Audience
What do Climate Scientists Think? Are humans responsible for observed warming?
Understanding your Audience
What factors have the effect of changing the Earth’s climate?
• Land
• Ocean
• Sun-Earth
• Atmosphere
Changes in Land and Ocean Circulation
What can change climate?
Precession26,000 years
Tilt 41,000 years
Eccentricity 100,000-413,000 years
The Milankovitch cycle, which has caused ice ages and warm periods in the past, is not causing the current changes we observe.
The Milankovitch Cycle
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
What can change Earth’s Climate?
Source: NOAA
Data Show:• Solar output approximately steady• Sunlight is not causing the current climate change
Am
ount
of
sunl
ight
(
Wat
ts/m
eter
2 )
1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006
Energy coming from the Sun (1979-2007) (measured at the top of the Earth’s Atmosphere)
Monthly solar data
Average solar data
What can change Earth’s Climate?
Greenhouse Gases
What can change Earth’s 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
What can change climate?
Why focus on CO2?
Amount of CO2
in the atmosphere- highest in 800,000 years
Historical rate: 30 ppm/1000 years
Current Rate: 30 ppm/last 17 years
satelliteobservations
balloondata
sea surfacetemps
permafrost melt
mtn. glacierretreat
polar ice capretreat
continentalice sheet
retreat
tree rings
coral reefcores
oceansediment
cores
ice cores
biological data
cave data
boreholes
How do we know? Rob Gillies slide modified, puzzle images from COMET
Warming
groundobservations
What data do climate scientists use?
The data …How do we know?
Looking at the graph, what can you conclude about 2008 temperatures?a) 2008 was the coolest year since 2000b) 2008 was warmer than any year before 1988c) Global warming has ended, global cooling is occurringd) Temperatures in 2008 are consistent with global warminge) Two years of temperature data are enough to make statements about
global warming
1988 2000
2008
Looking at the graph, what can you conclude about 2008 temperatures?a) 2008 was the coolest year since 2000b) 2008 was warmer than any year before 1988c) Global warming has ended, global cooling is occurringd) Temperatures in 2008 are consistent with global warminge) Two years of temperature data are enough to make statements about
global warming
Global average temperature changes in 2008
• Temperatures around the globe are not uniform
• One area does not give us the whole picture
• One time does not give us the whole pictureTemperature differences
Te
mp
era
ture
Diff
ere
nce
(°C
)co
mpa
red
to th
e y
ear
20
00
Image Courtesy: Dr. David Chapman
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
Only a few degrees?
• Last Ice Age: 7-13°F cooler
125,000 years ago: 1°F warmer, sea levels were 20ft higher
Why should we care?
Decreased water availability and increasing drought in mid-latitudes and semi-arid low latitudesIncreased damage from floods and stormsIncreasing fire risk Increased coastal flooding Up to 30% of species at increasing risk of extinction Significant extinctions
Energy Security/ Independence
Water
Increased water availability in moist tropics and high latitudes
Decreased water availability and increasing drought in mid-latitudes and semi-arid low latitudes
Hundreds of millions of people exposed to increased water stress
Food Productivity of all cereals decreases at low latitudes and in some other regions productivity decreases
Complex, localized negative impacts on subsistence farmers and fishers Tendencies for cereal productivity
to decrease in low latitudes and increase at mid-to high latitudes
Coasts
Increased damage from floods and stormsAbout 30% of global
Millions more people could
coastal wetlands lost
experience coastal flooding each year
Health
Increasing burden from malnutrition, diarrheal, cardio-respiratory and infectious diseasesIncreased morbidity and mortality from heat waves, floods, and droughtsChanged distribution of some disease vectors
Substantial burden on health services
Figure Modified from the IPCC Report SPM.2. Impacts will vary by extent of adaptation, rate of temperature change, and socio-economic pathway.
0°F 1.8°F 3.6°F 5.4°F 7.2°F 9°F
Key Impacts as a function of Increasing Global Average Temperature Change
Global mean annual temperature change relative to 1980-1999
Ecosystems
Significant extinctions around the globe
Up to 30% of species at increasing risk of extinction
Increased coral bleaching Most corals bleached Widespread coral mortalityIncreasing species range shifts
Increasing wildfire risk
Decreased water availability and increasing drought in mid-latitudes and semi-arid low latitudesIncreased damage from floods and stormsIncreasing fire risk Increased coastal flooding Up to 30% of species at increasing risk of extinction Significant extinctions
Energy Security/ Independence
Water
Increased water availability in moist tropics and high latitudes
Decreased water availability and increasing drought in mid-latitudes and semi-arid low latitudes
Hundreds of millions of people exposed to increased water stress
Food Productivity of all cereals decreases at low latitudes and in some other regions productivity decreases
Complex, localized negative impacts on subsistence farmers and fishers Tendencies for cereal productivity
to decrease in low latitudes and increase at mid-to high latitudes
Coasts
Increased damage from floods and stormsAbout 30% of global
Millions more people could
coastal wetlands lost
experience coastal flooding each year
Health
Increasing burden from malnutrition, diarrheal, cardio-respiratory and infectious diseasesIncreased morbidity and mortality from heat waves, floods, and droughtsChanged distribution of some disease vectors
Substantial burden on health services
0°F 1.8°F 3.6°F 5.4°F 7.2°F 9°F
Ecosystems
Significant extinctions around the globe
Up to 30% of species at increasing risk of extinction
Increased coral bleaching Most corals bleached Widespread coral mortalityIncreasing species range shifts
Increasing wildfire risk
1.8°F
stabilization
2×CO2
2.5×CO2
3×CO2 Up to 9.72°F
Warming by 2090-2099 relative to 1980-1999 for non-mitigation scenarios (Modified figure: SPM7 IPCC Report 2007)
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 SupplyWhy should we care?
Climate Change and National Security
“National Security and the Threat of Climate Change” 2007, CAN
Corporation
“Global Climate Change: National Security Implications” 2008, U.S. Army War College
“National Intelligence Assessment on the National Security Implications
of Global Climate Change to 2030” 2008, Deputy Director of National
Intelligence for Analysis
Why should we care?
Human health-heat waves more frequent and intense
Why should we care?
During heat waves death rate increases by 6%
Good news in the winter
• Warmer winters – less flu
Why should we care?
Milder temperatures = expanded range for many disease carriers
Why should we care?
Dengue hemorrhagiic fever first appeared in U.S.: 2005 – tropical borne disease
Experts worry that malaria could reappear
Air Pollution Worsens
Why should we care?
Higher humidity and warmer temperatures leads to more ozone and particulate matter forming and lasting longer
Air Pollution Worsens
• 1,000 more air-pollution-related deaths per year for every 1.8°F increase.
Why should we care?
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
• Last decade was 2°F warmer than the 100 year average
• Snow surveys show no clear long-term (80 year) trend in
mountain snowpack
• There is no clear linkage between recent global warming and precipitation within the basin of the Great Salt Lake
Utah Temperature (°F) 1895-2006
45
46
47
48
49
50
51
52
1895
1905
1915
1925
1935
1945
1955
1965
1975
1985
1995
2005
Line: 10 year running meanSource: National Climatic Data Center
Utah Temperature (°F) 1895-2006
45
46
47
48
49
50
51
52
1895
1905
1915
1925
1935
1945
1955
1965
1975
1985
1995
2005
Line: 10 year running meanSource: National Climatic Data Center
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 projections
• Mid and high latitudes wetter
• Most of subtropics drier
• Utah in the transition zone
Utah Snowpack and RunoffDecline 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 non-climatic 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/main3380176.shtml?source=search_story
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