Climate Change

EVPP 111 Lecture

Dr. Largen

Climate change in earth’s past

Climate change is neither new nor unusual

earth’s average surface temperature and climate have been changing throughout world’s 4.7 billion year history

sometimes gradually
over hundreds of millions of years
sometimes fairly quickly
over a few decades

Climate change in earth’s past

Climate change is neither new nor unusual

past temperature changes are estimated based on analysis of

plankton and isotopes in ocean sediments
ice cores from ancient glaciers
temperature measurements at different depths of earth’s crust
pollen from lake bottoms and bogs
tree rings
historical records
temperature measurements since 1860

Climate change in earth’s past

Climate change is neither new nor unusual

estimated average global temperature of atmosphere near earth’s surface has changed during 4 time scales in the past

900,000 years
22,000 years
1,000 years
140 years

Climate change in earth’s past

climate change during 4 time scales in the past

900,000 years

during this period, average global temperature has undergone prolonged periods of
global cooling

thick glacial ice covering much of earth’s surface for about 100,000 years

global warming

warmer, interglacial period lasting 10,000-12,5000 years, during which time most ice melts
we’ve been in such a period for past 10,000 years

with fluctuations in the range of +4 to -4 degree change

Climate change in earth’s past

climate change during 4 time scales in the past

22,000 years

end of ice age and increase in temperature to relatively stable plateau
with fluctuations in the range of +1 to -1 degree change

Climate change in earth’s past

climate change during 4 time scales in the past

1,000 years

with fluctuations in the range of +.5 to -.5 degree change

Climate change in earth’s past

climate change during 4 time scales in the past

140 years

with fluctuations in the range of <+.5 to <-.5 degree change from year to year
but with an upward trend during past 20 years

Climate change in earth’s past

Evidence of global warming

20th century was hottest century in past 1,000 years

since 1861, when atmospheric temperature record keeping began

average global temperature on troposphere near earth’s surface
has risen 0.6 degrees C

with most of that increase taking place since 1946

the 1990s was warmest decade on record
1998 warmest year since record keeping began in 1861

Climate change in earth’s past

Evidence of global warming

increased temperatures, melting ice caps, floating ice at earth’s poles

average global sea level rise of 10-15 cm in past 100 years

shrinking of some glaciers on tops of mountains in Alps, Andes, Himalayas, northern Cascades of Washington

northward migration of some warm-climate fish and trees

earlier spring arrival and later autumn frosts in some parts of world

more frequent occurrences of unusual weather patterns, such as droughts, warm spells, storms

Possible effects of a warmer world

A warmer global climate could have a number of harmful and beneficial effects

depending on where one lives

can look at these effects in several ways

by impact/resources

by region

Possible effects of a warmer world

Effects of a warmer global climate by resources/impact

weather extremes and shifts

forests

agriculture

sea levels and coastal areas

biodiversity

water resources

human population

human health

Possible effects of a warmer world - by impact/resource

weather extremes and shifts

prolonged heat waves and droughts

largest temperature increases will take place at poles

each one degree C increase in temperature will shift mid-latitude climate belts

increased flooding

an increase in frequency and intensity of storms

Possible effects of a warmer world - by impact/resource

weather extremes and shifts

prolonged heat waves and droughts

deserts will expand and droughts will grow more severe

especially in Africa and Asia

warmer soil, especially at higher latitudes, will speed up plant decomposition
and release more CO2

Possible effects of a warmer world - by impact/resource

weather extremes and shifts

largest temperature increases will take place at the poles

causing more melting of ice caps, resulting in
decrease in earth’s ability to reflect incoming sunlight (albedo)
amplify global warming
reduce amount of tundra available to Arctic animals (and migratory visitors)
cause declines in populations of some penguin species in Antarctic

Possible effects of a warmer world - by impact/resource

weather extremes and shifts

for each 1 degree C rise in earth’s average temperature

climate belts in mid-latitude regions would shift
toward earth’s poles by 100-150 km or upwards 150 m in altitude, causing

changes in areas where crops can be grown
changes in make-up and locations of forests

Possible effects of a warmer world - by impact/resource

weather extremes and shifts

an increase in frequency and intensity of

hurricanes
typhoons
tornadoes
violent storms

Possible effects of a warmer world - by impact/resource

forests

changes in forest composition and locations

disappearance of some forests

increased fires from drying

loss of habitat and wildlife species

Possible effects of a warmer world - by impact/resource

forests

tree species whose seeds are spread by wind

may not be able to migrate fast enough to keep up with climate shifts and would die out

existing forest trees may be more susceptible to fire and disease

Possible effects of a warmer world - by impact/resource

Agriculture

shifts in food-growing regions

changes in crop yields

increased irrigation demands

increased pests, crop diseases, and weeds in warmer areas

Possible effects of a warmer world - by impact/resource

Agriculture

shifts in food-growing regions

previously warm areas may become too cool for some or all crops
previously cool areas may become warm enough to support agriculture
previously dry areas may become wet
previously wet areas may become dry

Possible effects of a warmer world - by impact/resource

Agriculture

changes in crop yields

as temperature and precipitation levels in some areas move outside the optimal ranges for crops

Possible effects of a warmer world - by impact/resource

Agriculture

increased irrigation demands

as precipitation levels in some areas go from sufficient to support crops to insufficient to support crops

Possible effects of a warmer world - by impact/resource

Agriculture

increased pests, crop diseases, and weeds in warmer areas

all organisms have optimum temperature and moisture ranges

in some areas, increases in temperature and precipitation will create optimum growing conditions for pests, diseases, weeds

Possible effects of a warmer world - by impact/resource

Sea levels and coastal areas

rising sea levels

flooding of low-lying islands and coastal cities

flooding of coastal estuaries, wetlands, coral reefs

beach erosion

disruption of coastal fisheries

contamination of coastal aquifers with salt water

Possible effects of a warmer world - by impact/resource

Sea levels and coastal areas

global sea levels will rise

mainly because water expands slightly when heated
due to melting of land-based ice-sheets, if that happens

Possible effects of a warmer world - by impact/resource

Sea levels and coastal areas

large-scale melting of floating polar sea ice will not raise global seas levels

just as an ice cube in a glass of water does not raise the water level when it melts
but it will further contribute to global warming because sea ice helps cool earth by reflecting 80% of the sunlight it receives back into space
whereas the darker ocean without the ice would become a heat collector and absorb 80% of its input of sunlight

Possible effects of a warmer world - by impact/resource

Sea levels and coastal areas

in 2001 IPCC (Intergovernmental Panel on Climate Change) report, climate scientists projected

a rise in sea level of 9-88 cm (4-35in) during the 21st century
an increase at the upper end of the projection would

threaten estuaries
cause beach erosion
flood coastal regions
flood agricultural lowlands
submerge low lying islands

Possible effects of a warmer world - by impact/resource

Sea levels and coastal areas

2001 IPCC projects that a sea level increase at upper end of projection would

threaten estuaries

cause beach erosion

flood coastal regions

flood agricultural lowlands

contaminate freshwater coastal aquifers

submerge lowlying islands

Possible effects of a warmer world - by impact/resource

Sea levels and coastal areas

2001 IPCC projects that a sea level increase at upper end of projection would

threaten

one half of world’s

coastal estuaries
wetlands (1/3 of those in US)
coral reefs

causing a disruption in marine fisheries

Possible effects of a warmer world - by impact/resource

Sea levels and coastal areas

2001 IPCC projects that a sea level increase at upper end of projection would

cause sever beach erosion
especially along the east coast of the US
flood coastal regions
putting an estimated 200 million people living in 30 of the world’s largest coastal cities directly at risk

Possible effects of a warmer world - by impact/resource

Sea levels and coastal areas

2001 IPCC projects that a sea level increase at upper end of projection would

flood agricultural lowlands and deltas

in parts of Bangladesh, India and China

where much of the world’s rice is grown

contaminate freshwater coastal aquifers

with saltwater

submerge low lying islands

in the Pacific and Carribbean

Possible effects of a warmer world - by impact/resource

Biodiversity

extinction of some plant and animal species

loss of habitats

disruption of aquatic life

Possible effects of a warmer world - by impact/resource

Water resources

changes in water supply

decreased water quality

increased drought

increased flooding

Possible effects of a warmer world - by impact/resource

Human population

increased deaths

more environmental refugees

increased migration

Possible effects of a warmer world - by impact/resource

Human health

increased deaths from heat and disease

disruption of food and water supplies

spread of tropical diseases to temperate areas

increased respiratory disease

increased water pollution from coastal flooding

Possible effects of a warmer world - by region

2001 IPCC report projects major changes in different regions of the world during this century

Africa
Asia
Europe
Latin America
North America
Polar areas
small island states

Possible effects of a warmer world - by region

Africa

decreased grain yields

less water available

much higher temperatures in some countries

increased desertification

rising sea levels

Egypt at Nile delta, Dakar on west coast, in Nigeria at Niger delta, in Beira and Durban along southeastern African coast

Possible effects of a warmer world - by region

Asia

much higher temperatures in much of the continent

increased drought in some areas

increased floods in some areas

decreased food production

soil degradation

decreased food supply

rises in sea level and more intense tropical cyclones in coastal areas

such as Jakarta, Hong Kong,Tokyo, Shanghai, Bangkok
that could displace tens of millions of people

Possible effects of a warmer world - by region

Europe

moderate temperature increases in northern Europe

resulting increased agricultural productivity

increased drought in southern Europe

increased flooding in some coastal areas

such as Venice, Hamburg, St. Petersburg, Lisbon

disappearance of ~50% of Alpine glaciers

Possible effects of a warmer world - by region

Latin America

increased drought in some areas

increased flood in some coastal areas

such as Montevideo and Buenos Aires

lower yields of some key crops in many areas

such as Mexico and northeastern Brazil

Possible effects of a warmer world - by region

North America

much higher temperatures in Canada

increased food production in some areas of US

as a result of moderate warming

decreased crop yields in "bread baskets"

US Great Plains
Canada’s prairies

faster and earlier snowmelt in the Rockies

increasing spring flooding
making summers drier
increasing wildfires

Possible effects of a warmer world - by region

North America

increased sea level, coastal erosion, flooding, and greater risk of severe storms

especially along the Atlantic Coast

a 2000 report by US Global Climate Change Research Program projects

average temeprature in US is likely to increase by 3-5 degrees C (5-9 degrees F) by 2100

Possible effects of a warmer world - by region

Polar areas

very large temperature increases

increased ice melting which can

change climate patterns by altering global ocean circulation patterns
raise global sea levels

Possible effects of a warmer world - by region

Small island states

greatly increased coastal erosion

disappearance of some low lying islands as a result of sea level rise

Seychelles, Comoros, Tonga, American Somoa, Micronesia, Palau, Marshall Islands

Solutions: Dealing with the threat of climate change

What are our options?

there are four schools of thought

do nothing

do more research before acting

act now to reduce risks

act now as part of a "no regrets" strategy

Solutions: Dealing with the threat of climate change

Do nothing

~a dozen "expert" scientists contend that climate change from human activities is not a threat

a few popular press commentators and writers even claim global warming is a "hoax"

Solutions: Dealing with the threat of climate change

Do more research before acting

a second group of scientists and economists point to the considerable uncertainty about climate change and its effects

they call for more research before making such far-reaching economic and political decisions as

phasing out fossil fuels
sharply reducing deforestation

Solutions: Dealing with the threat of climate change

Act now to reduce risks from climate change

a third group of scientists and economists urge us to adopt a precautionary strategy

they believe the safest course is to take informed preventative action

before there is overwhelming scientific knowledge that would fully justify action

Solutions: Dealing with the threat of climate change

Act now to reduce risks from climate change

in 1997, more than 2500 scientists from a variety of disciplines signed

a "Scientists’ Statement on Global Climate Disruption" that concluded
"We endorse those [IPCC] reports and observe that further accumulation of greenhouse gases commits the earth irreversibly to further global climatic change and consequent ecological, economic and social disruption. The risks associated with such changes justify preventive action through reductions in emissions of greenhouse gases."

Solutions: Dealing with the threat of climate change

Act now to reduce risks from climate change

also in 1997, more than 2700 economists, led by 8 Nobel laureates, declared

"As economists, we believe that global climate change carries with it significant environmental, economic, social, and geopolitical risks and that preventive steps are justified."

Solutions: Dealing with the threat of climate change

Act now as part of a no regrets strategy

scientists and economists supporting this approach believe we such take key actions needed to slow atmospheric warming even is it is not a serious threat because

such actions lead to other important environmental, health, and economic benefits
for example, reductions in the combustion of fossil fuels will lead to reduction in air pollution that
harms and kills people
lowers food and timber productivity
decreases biodiversity

Solutions: Dealing with the threat of climate change

Those who favor doing nothing or waiting before acting point out that

there is a 50% chance we are overestimating the impact of rising greenhouse gases

those who favor acting now point out that

there is a 50% chance that we are underestimating the impact of greenhouse gases

Reducing the threat of climate change from human activities

A variety of solutions have been presented, falling into two main categories

prevention

cleanup

Reducing the threat of climate change from human activities

Prevention

cut fossil fuel use, especially coal

shift from coal and oil to natural gas

transfer energy efficiency and renewable energy technologies to developing countries

improve energy efficiency

shift to renewable energy resources

reduce deforestation

use more sustainable agriculture

slow population growth

Reducing the threat of climate change from human activities

Prevention

gradually implementing "prevention" solutions over next 20-30 years could simultaneously reduce threats from from

global warming
air pollution
deforestation
biodiversity loss

Reducing the threat of climate change from human activities

Cleanup

remove CO₂ from smokestacks and vehicle emissions

store (sequester) CO₂ by planting trees

sequester CO₂ underground

sequester CO₂ in soil

sequester CO₂ in the deep ocean

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions over the course of a decade through the implementation of a variety of regulatory actions

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

phasing out government subsidies for coal and oil

which amount to
app. $300 billion/year globally
app. $20 billion/year in US

retain subsidies for natural gas

which emits only about 50% CO2 per unit of energy as does coal
this would help ease the transition period (of 40-50 years) to alternative energy sources (increased energy efficiency, use of renewable energy)

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

increasing emphasis of reducing methane (CH4) emissions

methane absorbs and releases about 20 times as much heat per molecule as CO2

emissions reduction strategies include

capturing and burning methane gas released by landfills

reducing leaks from tanks, pipelines, other natural gas handling facilities

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

agreeing to global and national limits on GHG emissions and

encouraging industries and countries to meet these limits by selling and trading GHG emission permits in the marketplace
for example

a coal-burning power plant in Ohio could earn credits to allow some CO2 emissions by financing a CO2-removing tree planting project in Oregon or Costa Rica

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

allocating emissions equally on a per capita basis throughout the world

for example, each American on average would be allowed the same emissions as the average Indian

currently, the average American produces 25 times more CO2 than the average Indian

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

phasing in

output-based carbon taxes on each unit of CO2 emitted by fossil fuels
input-based energy taxes on each unit of fossil fuel that is burned

Costa Rica has enacted a 15% carbon tax and uses 1/3 of the revenues to finance tree-planting projects by farmers

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

greatly increase subsidies for energy-efficiency and renewable energy technologies

to help speed the shift to these alternatives

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

have each country agree to improve energy efficiency by a specified amount (such as 2-5%) each year until global emissions of GHGs have been cut by at least 50%

progress toward each country’s goal could be measured by calculating the annual change in its use of carbon fuel divided by its gross domestic product

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

fund the transfer of energy efficiency and renewable energy technologies from developed countries to developing countries

increasing the existing tax on each international currency transaction by 1/4 cent could finance this transfer by generating revenues of $200-$300 billion each year, funding projects such as
fuel-cell factories in South Africa
wind farms in India
solar-powered hydrogen farms in the sunny Middle East

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

increasing the use of nuclear power

it produces only about 1/6 as much CO2 per unit of electricity generated as coal

opposed by many because

danger os large scale radiation release
high cost, even with large subsidies
issues related to handling and storing radioactive waste

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

using regulation and subsidies to

reduce deforestation
increase use of sustainable agriculture

Using government regulation to reduce greenhouse gas emissions

Governments could significantly reduce CO₂ emissions

establish national policies and fund international efforts to slow population growth

if we cut GHG emissions in 1/2 but the population doubles, we’re back where we started

How can we remove CO2 from the atmosphere

Scientists are evaluating several ways to remove CO2 from atmosphere or smokestacks and store ( or sequester) it in

immature trees

plants that store it in the soil

deep underground reservoirs

deep ocean

How can we remove CO2 from the atmosphere

Possible ways to remove CO2

plant trees

over an area the size of Australia
however, such a global reforestation project would require every person in the world to plant and tend to about 1000 trees each year

and would offset only about 3 years of our current CO2 emissions from burning fossil fuels

How can we remove CO2 from the atmosphere

Possible ways to remove CO2

collect CO2 from smokestacks and

pump it deep underground into unmineable coal seams and abandoned oil fields

injecting it into the deep ocean

would require costly investment in materials, transportation, infrastructure

could upset global carbon cycle

could harm sea life in some way

current methods only remove about 30% of CO2 from smokestacks any way

How can we remove CO2 from the atmosphere

Can technofixes save us? Some proposals

adding iron to ocean to stimulate growth of marine algae

whose photosynthesis would sequester carbon

but it would return to atmosphere short time later

unfurling gigantic soil-surfaced sun mirrors in space or on about 50,000 orbiting satelittes to reduce solar input

releasing trillions of reflective balloons filled with helium

injecting sunlight reflecting sulfate particles or firing sulfur dioxide cannonballs into the stratosphere

How can we remove CO2 from the atmosphere

Most releastic approach

improve energy efficieny

shift to renewables

Climate Change:
El Nino-Southern Oscillation

El Nino

name originally coined in late 1800s by Peruvian fishermen as the name for a seasonal shift in the current pattern off the coast of Ecuador and Peru

that occurred around Chrsitmas time
thus El Nino (Spanish for "Christ child)
would replace the cold, nutrient rich water in which they usually fished with less productive, warm southward flowing water

slightly reducing the fish population and giving the fishermen some time off

Climate Change:
El Nino-Southern Oscillation

El Nino

now the name refers to a catastrophic version of that original annual event

part of a phenomenon known as El Nino-Southern Oscillation (ENSO)

a continual but irregular cycle of shifts in ocean and atmospheric conditions that affect the globe

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

normally, the Pacific Ocean is fanned by constantly blowing east-to-west trade winds

which push away from the coast the warm surface water along western coasts of Peru, Chile, Ecuador
allowing cold, nutrient-rich water from depths to well up (upwelling) into the place of the warm water that has been pushed away

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

warm water that was pushed away from the coast "piles" up in western portion f the Pacific Ocean
resulting in the waters of the western Pacific Ocean being several degrees warmer and about one meter higher than the waters in the eastern portion of the Pacific

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

if east-to-west trade winds slacken briefly

warm water begins to slosh back across the Pacific Ocean from west to east
ocean & atmosphere can conspire to ensure that it keeps happening
the warmer the eastern ocean gets, the warmer and lighter the air above it becomes

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

the warmer the eastern ocean gets, the warmer and lighter the air above it becomes

and, hence, the more similar to the air on the western side (of the ocean)
reducing difference in pressure across ocean
since a pressure difference is what makes the wind blow, a lack thereof causes the easterly trade winds to weaken
the continued reduction in winds allows warm water to continue its eastward advance

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

end result is to shift the weather systems of the western Pacific Ocean about 6000km eastward

tropical rainstorms that usually drench Indonesia and the Philippines are caused when seawater abutting these islands cause the air above it to rise, cool and condense into clouds
when the warm water moves east, so do the clouds, leaving previously rainy Indonesia and the Philippines in drought

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

ecological effects during an El Nino

in the waters of Peru and northern Chile
commercial fish stocks virtually disappear

the commercially valuable anchovy fisheries of Peru were essentially destroyed by the 1972 El Nino

plankton dropped to 1/20th of their normal abundance

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

ecological effects during an El Nino

weather effects are propagated across world’s weather systems
violent winter storms, accompanied by flooding, lash the coast of California
colder and wetter winters occur in Florida and along Gulf Coast
American midwest and the Mid-east experience heavier than usual rains

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

although effects of El Nino are clear, what triggers them is not

models suggest that the type of climate change that triggers El Nino is chaotic
wind and ocean currents return again and again to the same condition but never in a regular pattern

small nudges can send them off in many different directions

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

in the news, Washington Post, "Science Notebook, El Nino: The Sequel", 1/14/02

El Nino may appear this spring after a 5 year absence
prediction based on detection of warming over tropical Pacific Ocean
its return would likely cause
drier-than-normal fall in Pacific Northwest
wetter-than-normal winter in Gulf Coast and maybe California
warmer-than-normal in Great Plains

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

noteworthy El Ninos

1982 - 1983: 2100 deaths, $13 billion in damages

Austraila, already in midst of worst drought in a century, suffered losses that cost billions

wildfires, catastrophic agricultural & livestock losses

drought in sub-Saharan Africa

countries that were normally food-exporting had to turn to international community for help

southern Ecuador and northern Peru

app. 100 inches of rain fell in 6 month period

Climate Change:
El Nino-Southern Oscillation

El Nino-Southern Oscillation (ENSO)

noteworthy El Ninos

1997 - 1998:
California lashed by storms for months

1400 homes damaged or destroyed

Florida ravaged by series of tornadoes, killing 39
Panama Canal officials had to restrict shipping due to low water levels
Indonesia suffered forest and peat fires producing smoke that affected southeast Asia