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MET 112
MET 112 Global Climate Change: Lecture 10
Climate Change Impacts: Present
and Future
Outline:
Dr. Eugene Cordero
 Fingerprints of climate change
 Future impacts
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Climate Change Impacts
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 What signals would we expect from a warmer world?
– Higher average temperature
– Higher maximum temperatures
– Higher minimum temperatures
– More precipitation
– Higher sea level
 What ‘evidence’ do we have for changes in the 20th
century?
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Fingerprints and harbingers of climate
change
 FINGERPRINTS: Direct manifestations of a
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widespread and long-term trend toward warmer
global temperatures
–
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Heat waves and periods of unusually warm weather
Ocean warming, sea-level rise and coastal flooding
Glaciers melting
Arctic and Antarctic warming
Increases in sea level
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Fingerprints and harbingers of climate
change
 HARBINGERS: Events that foreshadow the types
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of impacts likely to become more frequent and
widespread with continued warming.
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Spreading disease (i.e. mosquito carrying)
Earlier spring arrival
Plant and animal range shifts and population changes
Coral reef bleaching
Downpours, heavy snowfalls, and flooding
Droughts and fires
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Impacts over the last 100 years
Fingerprints of climate change
Indicators
of Climate
Change
Ocean warming
Stratosphere cooling
Troposphere warming
Temperature trends
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 Troposphere (0 - ~ 10km)
 Stratosphere (10 – 50 km)

Surface temperatures are warming – (Certain)

Middle troposphere is also warming (Very likely)
– Early satellite data showed some cooling, but now that
seemed to be due to instrument error.

Upper atmosphere is cooling (Certain)
– Why cooling?
More energy trapped in troposphere.
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Water vapor feedback

Recall how the water vapor feedback works
– Increase in temp
– Increase evaporation
– Increase in water vapor in atmosphere
 Water vapor is a greenhouse gas
– Increase in greenhouse effect
– Further warming (positive feedback)

Current models suggest that the water vapor feedback is
responsible for about the same amount of warming as
warming from increases in CO2.

The importance of this feedback is still being investigated.
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Global mean surface temperatures have
increased
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The Land and Oceans have both warmed
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Precipitation patterns have changed
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Svalbard,
Norway (79N)
`
Arctic
Sea Level rise
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 Increased risk of floods, potentially displacing tens
of millions of people due to
– sea level rise and heavy rainfall events
 Bangladesh is projected to lose about 17% of its
land area with a sea level rise of one meter –
– very difficult to adapt due to lack of adaptive
capacity
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Recent Sea Level Changes
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Branching coral
Brain coral
Increase in coral bleaching events: due to warmer ocean
temperatures
http://www.climatehotmap.org/
Extreme Weather Events are Projected to Increase
Projected changes during the 21st
century
Examples of impacts
• Higher maximum temperatures; • Increased mortality in old people
more hot days and heatwaves
in urban areas
over nearly all land areas (very • Damage to crops
likely)
• Heat stress on livestock
• Higher minimum temperatures; • Extended range of pests and
fewer cold days frost days and
diseases
cold spells over nearly all land • Loss of some crop/fruit
areas (very likely)
slides, mudslides, damage to
• more intense precipitation events • Land
property and increased insurance
over many areas (very likely)
costs
• increased summer drying over • Reduced rangeland productivity,
most mid-latitude continental
increased wildfires, decreased
interiors and associated risk of
hydropower
drought (likely)
• increase in tropical cyclone peak • Damage to various ecological and
socioeconomic systems
wind intensity, mean and peak
precipitation intensities (likely)
Future impacts due to
climate change
More adverse than beneficial impacts on biological and
socioeconomic systems are projected
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As a result of warming, plant species
would be expected to migrate
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North in the Southern Hemisphere
North in the Northern Hemisphere
South in the Northern Hemisphere
South in the Southern Hemisphere
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Where would you expect to see the
strongest evidence of climate change?
Tropical latitudes
Midlatitude deserts
Midlatitude oceans
High latitudes
High altitude mountains
54%
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14%
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If ice melt was to stop even though average
temperatures continue to warm, how would
sea level respond
1. Sea level would continue to rise 79%
2. Sea level would reach an equilibrium
3. Sea level would decrease
16%
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Impacts on water and agriculture
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 Water availability
– Increase in some in some water-scarce regions,
– Decrease in many water scarce regions
– Globally, fresh water become more scarce
 Increased agricultural productivity in some midlatitude regions; reduction in the tropics and subtropics
– Overall impact is negative
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Effect on human health
 Reduced winter mortality in
– mid- and high-latitudes
 Increased incidence of heat stress mortality
– Tropics and midlatitudes
 Increased incidence diseases in the tropics and
sub-tropics
– such as malaria and
– water-borne diseases such as cholera,
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Developing countries are the most vulnerable to
climate change
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 Impacts are worse –
– already more flood and drought prone
– large share of the economy is in climate sensitive
sectors
 Lower capacity to adapt
– because of a lack of financial and technological
capacity
 Climate change is likely to impact disproportionately
upon the poorest countries and the poorest persons
within countries,
 Net market sector effects are expected to be negative
in most developing countries
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Climate change and California
Average Temperature:
Winter Summer –
1. Coastal cities:
2. Human health:
3. Water resources:
4. Agriculture:
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Report Issued in 2004
 Sections include:
– Climate
projections
– Sea levels
– Extreme heat
– Health impacts
– Water resource
– Agriculture and
vegetation
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Climate change and California
Average Temperature:
Winter - warmer winters - snowpack declines
by 70-90% by 2090
Summer – warmer summers (5-15F by 2090)
1. Coastal cities: coastal erosion by sea level
rise.
2. Human health: Urban air pollution/heat
extremes impact most vulnerable
3. Water resources: Total water, but early runoff
from Sierras costly to adapt.
4. Agriculture: Major challenge to various crops
industries.
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Weather-related economic damages have
increased
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2020s
2050s
2080s
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