Transcript File - BSC Economics

Lecture 5: Understanding Climate Change
Fiction, Facts, Uncertainties, Challenges & Impacts
Shakeel Hayat
26th Oct 2011
[email protected]
Lecture Outline
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Introduction
What the unconvinced people are saying
Facts
Uncertainties
Challenges
Human impacts on climate change
Climate change impacts on humans & the environment
What can we do about it?
Concluding remarks
What the unconvinced people are saying…
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“Theory remains entirely unproved.”
“One-in-three chance … that experts are wrong.”
“Models are incapable of handling … water vapor.”
“If the weather folk can’t figure out what’s happening for the
rest of the week, how can they tell us what the climate will
be for the next 50 years?”
“Guess what? Antarctica’s getting colder, not warmer.”
“Global warming is still just a theory.”
Facts…
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Global mean temperature has been going up in the last 140
years.
The magnitude of this variability does not exceed natural
variability.
Concentration of carbon dioxide has been going up as well
as other greenhouse gases.
Climate change involves the entire “earth system” not just
the atmosphere.
Future projections face uncertainties in emission
production, modeling, and impacts.
Several thousand scientists from 40+ countries all over the
world have been involved in Ecosystem Assessment
Global Mean Temperature
(140 year record)
Global Climate System
Challenges
A. Nature of climate system
1.
Analysis must consider entire climate system and all of
humanity
2. Extensive natural climate variability
3.
Global connections for both climate forcing and climatic
response
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Uncertainties in outcomes involve uncertainties in many
components
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A small change in global means can translate to large changes
in local means/extremes
B. Needs for research
1.
Improve data – longer data, error analysis, more global coverage
2. Improve theory
3. Improve models
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Separating naturally-induced fluctuations from human effects
C. Nature of people
1. Implement controls on human impacts on the environment
2. World cooperation
3. Look at ourselves
Human Impacts on Climate Change
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Types of impacts
Focus on greenhouse gases – primarily CO2
Driving forces for the future
Basic scenarios
Scenario outcomes
Types of Human Impacts
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Increase in greenhouse gases
Change in surface conditions (e.g. albedo, wind, evaporation)
Change in clouds (e.g. contrails, pollutants, etc.)
Driving Forces for Future Human Impacts
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Population
Economy (income per capita and regional differences)
Technology
a. Energy production – fossil fuels and non-fossil fuels
b. Energy use efficiency
c. Land use
Energy structure: Coal – Oil/Gas – Renewable / Nuclear
Land use: Forests – Croplands & Energy Biomass -Other
(grasslands, etc.)
Agriculture
Climate Change Impacts on Humans & the
Environment
A. Terrestrial ecosystems
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Agriculture
2.
Forests
3.
Desert and desertification
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Hydrology and water resources
B. Ocean systems
1. Sea level
2. Coastal zones and marine ecosystems
C. Human “systems”
1. Settlements, energy and industry
2. Economic, insurance, and other financial services
3.
Human health
a. Vector borne diseases
b. Water-borne and food-borne diseases
c. Food supply
d. Air pollution
e. Ozone and ultraviolet radiation
D. Atmospheric systems
1. Weather
2. Storms
3. Floods and droughts
Water Availability Resources
Water availability in 2050
for the present climatic
conditions and for three
transient climate scenarios.
(m3 / year / person)
Sea Level Rise Impacts
Vector-Borne Disease Susceptibility
Human Responses to Climate Change
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Why should we care?
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Modify our own life style
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Mitigation and adaptation
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Modify national and global practice
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Influencing public policy
Why Should We Care?
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We don’t know exactly what will happen with global warming or what
the impacts will be. And where or when they will hit hardest.
But scientists have a pretty good general idea of what’s to come. They
tell us the possible impacts could be far-reaching and could cause
serious problems:
Sea level will continue to rise, eroding beaches and increasing the
damage from storms and leading to loss of wetland habitats. Some
island nations will disappear.
Increasing temperatures are likely to affect human health:
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Warmer temperatures mean mosquitoes will spread in areas that
were previously too cold for them to survive. Mosquitoes carry
infectious diseases like malaria and encephalitis.
Ground-level ozone pollution will likely worsen, increasing
respiratory diseases like asthma.
Deaths from heat waves will rise.
Some plants and animals may face extinction if habitat changes.
Changing weather patterns could affect agriculture. Northern states
could actually experience longer growing seasons. The U.S. Great
Plains could have frequent droughts.
Some forests may disappear, leading to extinction of wildlife species—
changes in biodiversity.
Economic effects: Billions of dollars in property damage from sea level
rise and worsening storms.
What Can We Do About Global Warming?
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There are simple steps each of us can take that will help reduce our emissions of
greenhouse gases. Just a few examples:
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Recycling saves the energy required to manufacture new
products.
Give your family car a day off by riding your bike, taking
the bus, or walking.
Plant trees – they absorb carbon dioxide.
Read and learn about global warming.
Save electricity by turning off the TV and lights when
you’re through with them.
Go solar – a solar system to provide hot water can
reduce your family’s carbon emissions by about 720
pounds a year.
Encourage others to take these simple actions.
Preserve forests – they act as carbon dioxide “sinks” –
in other words, they absorb carbon dioxide.
Develop renewable energy technologies to reduce
dependence on fossil fuels.
Use energy more efficiently. For example, the federal
government has a variety of voluntary partnership
programs with industry to reduce greenhouse gas
emissions by using energy more efficiently.
Concluding Remarks
1. Research activities continue to increase
a.
North-South Carbon Program
b.
Climate modeling enhancement
c.
Regional climate change studies
2. Government Plans
a.
Enhanced support for research
b.
Research technology to help in mitigation
(e.g. Hydrogen car)
3.
Still a long way to go.........................