Transcript Lectures Chap 11-13 - Saint Leo University Faculty

Chapter 11
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Climate forcings: changes in some parts of
the Earth’s energy budget that affects the
temperature of the Earth
Look at the past, (models are changing to
agree with the experimental data for past
climate)
Predict the future
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Land and sea (different heat capacities)
temperatures are recorded separately
“Urban heat island effect” cities are warmer by
about 5 °C from sunlight absorbed by
pavement (sensible heat), the heat is emitted
at night
“Countryside” sunlight hits land, water
evaporates and contains latent heat, latent
heat releases as water condenses
Removing urban
temperatures from the
models has only a small
effect, the result – the planet
is still warming
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Records changed in 1942
<1942, a wood or canvas bucket provided
some cooling, and were thrown at various
depths.
>1942 the SST was measured in the engine
room as cooling water entered the engine
room.
The sea surface temperature agrees with the
land, the Earth’s surface is warming
The agreement between the
land and the sea
temperatures warming are
based on thousands of
locations globally, and not
by “cherry picking” only
selected areas.
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Measures oxygen molecules in the rotational
mode, they emit microwave radiation, which
is a longer and lower energy wave than
infrared.
Temperature estimates from satellites used to
disagree with the thermometer reading on
the ground, but this was caused by errors in
data processing that have now been fixed
Is this a problem?
Measurements are made from a series
of satellites
 They are all calibrated against each
other
 Raw data is corrected for things like
changes in the orbit of the satellite
 Satellites are ideal for global
“snapshots”
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 Glaciers
are melting, and they
are routinely monitored and
measured
 Another confirmation that the
Earth is warming
Climate forcings are different factors
that can change the climate
 The comparison is the effect on the
Earth’s energy budget (W/m2)
 The radiative forcing in W/m2 allows
us to compare the causes of climate
change on a roughly equal footing
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state variable is W/m2
 These changes include:
◦ Solar variability
◦ Greenhouse gasses
◦ Anthropogenic aerosols
◦ Volcanic particulate emissions to
the atmosphere
The energy imbalance immediately after the
change happened, but before the climate
responds to the change
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Chapter 4 – the climate sensitivity
benchmark was the CO2 doubling, ΔT2X
Earths temperature rises in proportion the
number of CO2 doublings, the estimate is
3°C
Chapter 11 – the climate sensitivity
parameter relates the equilibrium warming to
the radiative forcing
ΔTR ~ 0.75 / W/m2
~ 1.5 W / m2
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Have the climate forcings changed with time?
Solar intensity:
Measured by satellite
No atmospheric interference
Data collection since 1975
The sun has an eleven year sunspot cycle
<1975, observations in the sunspot cycle for about
400 years
◦ Also measured in ice cores, checking the ratio of
cosmogenic isotopes Be-10, and C-14
◦ Weaker sun, less cosmic ray deflection, more
isotopes
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 Maunder
Minimum, 1650 – 1700
 A period of no sunspots
 Coldest period in Europe in the
last 1000 years
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If the eruption is strong enough, it can send
particulate into the stratosphere and cool the
planet for several years
Mt. Pinatubo in the Philippines erupted in
1991
1900 – 1950, the temperature rose
1950 – 1970, the temperature declined
1970 – present time, the temperature is
rising
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Intergovernmental panel on climate change,
had their meeting in Warsaw last month
The 2007 assessment report:
19 models were run twice using the same
scenarios
They were run with human contributions, and
they were run without human contributions
With human contribution, the model
simulates the temperature increase since
1970
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The smoking gun for global warming is the
rise in temperature since 1970
The models can’t reproduce the
temperature change that has been
measured without considering the human
contribution of greenhouse gasses to the
atmosphere
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There would have to be some other way to
explain the recent warming since 1970
There would have to be a reason to throw
out the greenhouse effect theory – or –
explain why increasing CO2 would not block
outgoing IR energy by absorbing the IR in
its vibrational energy mode
No thermometers for most of the
period, must be determined by proxy
measurement
 Look at the thickness of annual tree
ring layers in the wood
 Bore holes for surface temperature
proxy measurements
 Condition of ice sheets and mountain
glaciers
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There was a warm period from 800 –
1200, called the Medieval Climate
Anomaly
 There was a cold period from 1350 –
1800, called the Little Ice Age
 The Little Ice Age corresponded to the
Maunder Minimum, a period of no
sunspots
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Last Glacial Maximum was 18,000 years ago
Continents were covered in massive ice
sheets
There was a polar amplification, high
latitudes felt more of an effect than the
tropics
The atmosphere had less CO2 and CH4
Ice, ice sheets, sea ice and snow changed
Earth’s albedo
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55 million years ago, Paleocene, Eocene
Thermal Maximum
The ratio of C-12 / C-13 in deep ocean
CaCO3 sediments indicated that there was a
sizeable release of C to the atmosphere or
the ocean
The early release is an analogy to the fossil
fuel CO2 release
As with the Last Glacial Maximum, it will be
many thousands of years for temperatures to
recover to their natural baseline values after
a sizeable CO2 release
But what is the natural baseline
temperature value?
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The past few years have been warmer than
the thermometer records of the past 140
years and warmer than reconstructed records
over the past 1,000 years
Climate change is driven by natural and
human-induced changes in radiative forcing,
including volcanic eruptions, solar variability,
greenhouse gases, and human released
aerosols.
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Models cannot explain the rise in global
temperatures since about 1970 without
including anthropogenic forcing. This is the
smoking gun for a human impact on climate.
Chapter 12
Drought and
storms, and sea
level, not just the
warming
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IPCC
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Climate Central
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GRACE – Gravity Recovery and Climate
Experiment (March 2002, failed in 2011)
NASA's gravity field satellite mission GRACE
has provided nine years worth of data about
changes in Earth's gravity field. The analysis
of the data from the two satellites on the
mission was published in the Nature
Geoscience Journal, which looks at the
melting of our Earth's ice sheets.
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ICESat – Ice, Cloud and Land Evaluation Satellite
(January 12, 2003, 3rd laser failed 2010)
ICESat, part of NASA's Earth Observing System,
was a satellite mission for measuring ice sheet
mass balance, cloud and aerosol heights, as well
as land topography and vegetation
characteristics. Wikipedia
After seven years in orbit and 18 laseroperations campaigns, the ICESat's science
mission ended due to the failure of its primary
instrument. http://nsidc.org/data/icesat/
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Warmer temperatures are not going to be
the most important thing to affect people.
There will be more impact from:
◦ Drought
◦ Storms
◦ Regional rather than global effects
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Temperature rise from 1 – 6 °C
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Big range, why the uncertainty? Two reasons:
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1. What is the temperature response to
additional CO2?
2. How much CO2 will be released?
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Changes in rainfall patterns and amounts
Changes in a few degrees changes the
landscape
Comparison to the last ice-age, global
temperatures were 5-6 ° cooler – huge
impact!
Europe and North America were covered in
huge ice sheets
Pollen data shows huge changes in vegetation
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Changing climate caused the demise of two
classical civilizations
The Mayan and the Anasazi civilizations
collapsed in several stages that correlated
with strong, decades long droughts.
 High
latitudes are warming faster
 Permafrost melts, collapsing the
soil
 Houses and trees tilt
 Lakes disappear
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1995 Chicago
1999 Mid Atlantic area
Europe 2003 (France) 100 year event?
Happened again in 2006
2010 Russia
2011 Texas
2012 “summer in March” in the US Midwest
Many more, causing very high heat related
morality rates
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CDC document on heat events
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Heat is the most lethal type of weather
phenomenon
High mortality
Psychological stress (higher crime rates)
Power outages
Wildfires
Physical damage
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Softening pavement
Buckling railroad tracks
Burst water lines
Power transformers detonating
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Changing climate rearranges weather
patterns and water supplies that are difficult
to forecast
Hadley circulation – expected to increase in a
warmer climate, intensifying rainfall at the
equator and causing further drying in the
desert regions.
Projection for monsoons in South China and
India to become stronger and stormier
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Droughts driven by a change in the water
pattern are expected to increase, particularly
in:
◦ American Southwest
◦ Mediterranean
◦ Australia
The loss of plants amplifies the drought and
also makes it harder to break out of a drought.
The carrying capacity of the land depends on
rainfall.
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But not uniformly!
The tropical cyclones are predicted to be
stronger and more frequent
The storm seasons have not validated this
prediction
In fact, the hurricane season that ended last
weekend was the mildest storm season since
1982 
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Rising sea level – the change is slow,
and seas will continue to rise for
centuries, for two reasons:
1. Thermal expansion of water
(0.5-2.0 m)
2. Melting ice on land, glaciers and ice
sheets
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Floating ice, sea ice, and ice shelves do not
increase sea level when it melts because the
ice already displaces its own weight in water
Archimedes Principle – when floating ice
melts, its water exactly fills the hole that the
ice had previously occupied.
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The ice sheets in Greenland and Antarctica
are the slow giants contributing to the rise in
sea level.
Together they could raise sea level by 70 m
70 m = 230 feet
The elevation of St. Leo is 167 feet
Sea level could rise as high as a mid-rise, 14
story hotel on Miami Beach
Florida’s highest elevation is 345 feet
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Ice shelves collapse abruptly, no way to add
this into the models
In 2002, Larsen Ice Shelf took a few months
for an area the size of Rhode Island to
collapse into ice bergs
When the ice collapses, or melts, the land
usually rises! The weight of the ice is gone
and the crust lifts slightly higher in elevation
IPCC forecast for 0.5-1.0 m increase is totally
unrealistic
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Occasionally there is a flip-flop of climate
Change occurs over a few years, but may last
for centuries
Presently, the Holocene Period, the climate
has been stable for the last 10,000 years
20,000 – 80,000 years ago there were 1,000
year temperature swings called DansgaardOeschger Events
Sudden warming of 10-15°C in a few years
followed by gradual cooling
Most intense in the high Northern latitudes
The land surface depends on the local
climate
 Includes temperature, precipitation,
and the human footprint (agriculture,
decorative lawns, and pavement)
 Insects move easily; trees do not
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The Arctic, polar bear habitat may be
restricted to the northern parts of Greenland
The tropical oceans, coral reefs are
particularly sensitive to pollution in runoff
and changes in temperature
Corals respond to stress by “coral bleaching”
Symbiotic algae are ejected, and coral reefs
soon die
The climate change will amplify
the extinction trends by
demanding that natural
ecosystems get up and move,
just when they are restricted by
human land use and least able
to do so.
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Changes in water availability
Melting mountain glaciers and snowpack are
a summertime source of drinking water in:
Himalayas, for India, Pakistan, Uzbekistan
Andes, for Lima, La Pas, Quito
North America, in the Pacific Northwest
The growers may have to change
crops to meet the changing conditions
 Presently, the world food production
is greater that consumption – can it
continue?
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There is a concern about tropical diseases
spreading with the warmer climate
Impacts will be stronger in the tropics and
developing nations where there is less wealth
to buffer setbacks from the weather and less
infrastructure to deal with the aftermath.
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Climate models that simulate the past predict
huge climate changes in the future, relative to
what civilized humanity has ever seen before.
Drought is one of the most dangerous
aspects of climate change, as continental
interiors warm and dry out, despite a global
increase in the amount of rainfall overall.
Extreme weather events are already getting
stronger and this trend is expected to
continue.
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Sea level will continue to rise for centuries
from thermal expansion and melting land ice.
Chapter 13
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Tragedy of the Commons, the moral is that
everyone would be better off if they cooperated!
A cost that is not paid by the decision maker
is called an external cost.
The cost of climate change is not only paid by
people who are responsible but by everyone,
soon, and far into the future.
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A regulatory agency allocates permits for
emission of climate forcing agents such as
CO2
The total number of permits they issue is a
lower overall rate of emission
If a company has lower emissions than the
permit allows, it can sell its allocation as
carbon offsets
Companies already exist whose function is to
sell carbon offsets, using the money to find
ways of cutting carbon dioxide emissions
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Carbon tax and cap and trade accomplish the
same things in the end
The tax specifies the price and allows the
market to choose the emission, whereas the
cap and trade sets emissions and lets the
market choose the price
Local issues, easy to solve
Regional issues tend to be us vs. them
Global warming is the most global of issues
and the most complicated type to solve
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1988, agencies of the U.N. formed the IPCC
Their role is to assess “the scientific,
technical and socio-economic information
relevant to understanding the scientific
basis of risk of human-induced climate
change, its potential impacts and options
for adaptation and mitigation.”
Purpose is to publish reports summarizing
the scientific literature
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WGI – deals with the scientific basis for the
climate change forecast
WGII – deals with the impacts of climate
change on the natural and human world
WGIII – assess options for limiting
greenhouse gas emissions or otherwise
avoiding climate change
Consist of chapters and various levels of
summaries
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1990, the first IPPC report was that it was not yet
possible to detect human-induced global
warming (models left out human induced
aerosols and changes in solar intensity)
1995, the second report fixed the models, and
issued the now famous statement that “the
balance of evidence suggests a discernable
human influence on global climate.”
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As a result, a 1997 meeting in Kyoto, Japan
drafted the Kyoto Protocol which attempted
to limit global CO2 emissions to about 6%
below 1990 emission levels by the year 2010
The treaty cam into force when countries
accounting for 55% of the emissions agreed
to the terms
U.S. withdrew under the Bush administration
in 2001
Russia agreed in 2005, putting the agreement
into force without the U.S.
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The agreement has no “teeth”
The rate of CO2 emission has grown rather
than decline
Kyoto Protocol due to expire in 2012
“Only two things are clear after the climate
meeting in Doha, Qatar: a weak Kyoto
Protocol will remain in place for a few more
years and more negotiations are needed”
http://www.scientificamerican.com/article.cfm?id=climateconference-renews-kyoto-protocol-but-looks-to-successor
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The Montreal Protocol on Substances that
Deplete the Ozone Layer was adopted in
1987 as an international treaty to eliminate
the production and consumption of ozonedepleting chemicals.(www.worldbank.org)
The agreement to limit CFC emission to the
atmosphere to save the ozone in the
stratosphere has done more to slow global
warming than the Kyoto Protocol
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The economy is much harder to forecast than
the weather, otherwise we would all be
wealthy
More and cheaper CO2 emission cuts are
possible in the next few decades from
improvement in energy efficiency that from
new alternative energy sources
Costs of avoiding climate change would be
comparable to the costs of deciding to go to
war - significant, but not prohibitive
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Goal of IPCC, “to prevent dangerous
anthropogenic interference with the climate
system” (lacks definition)
Accepted benchmark target is 2°C
Earth has been warmer – probably 400,000
years ago when the Earth resembled today, a
time called Stage 11 (look at fig.8-4)
>2°C isn’t really a danger limit, but
surpassing it makes the projected damages
go up rather drastically
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How fast is the climate going to change?
IPCC says that the warming should be slow
enough for ecosystems to adapt naturally,
with no threat to food production, and to
enable economic development to proceed in a
sustainable manner
In other words – the transition to a new climate
regime should be slow enough for natural and
human systems to adapt.
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The greatest short term solution is
conservation
Most of the cheapest solutions involve energy
efficiency rather than new energy sources.
Nuclear energy generates no carbon, and we
know it works, but the Uranium is in short
supply
Converting U to Pu, increasing the yield 50x
Downside, Pu is also a weapons-grade
radioactive element-not everyone wants
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Very clean alternative, and not so
unattractive!
They supply 7% of Denmark's power, and
0.3% of the global energy.
It’s growing by 30% a year, scaling up the
production by 50x would generate about
2 TW of energy.
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Solar thermal, lower tech, concentrate
sunlight with mirrors to heat water, generate
steam, turn a turbine and generate electricity
Photovoltaic uses semi-conductor
technology, it’s very expensive, but doable.
Generally, no one solution exists, it will need
to be a combined effort, or a new technology
that doesn’t exist yet.
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It’s very easy to produce hydrogen from
water, but it requires electricity
Hydrogen can be produced from the
gasification of coal – probably messy
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Requires a pressurized container
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Extremely flammable
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Most countries are not capturing carbon dioxide
emissions and storing them underground,
because the process is expensive.
A closed-loop system that injects CO2 into hot
brine brought to the surface from deep
underground could make CO2 storage
economical by providing geothermal energy and
methane for fuel. The CO2-laden brine would be
sent back down for permanent storage.
Calculations show that enough deep brine exists
along the U.S. Gulf Coast to store one sixth of
the country's CO2 emissions and to meet one
sixth of its demand for natural gas annually.
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When oceanographers add iron to the
Southern Ocean, the plankton bloom – they
are primary producers
The idea is that the plankton would grow, die,
and sink to the deep ocean, taking the carbon
with them
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Generate a haze in the stratosphere by
releasing sulfur of some other chemical
Aerosols cool the Earth by scattering sunlight
Putting particles in the stratosphere is that no
rain originates there, so the injected aerosols
would remain for several years
Shoot sulfur in canisters from large cannons
Or just put sulfur in jet fuel and let the air
traffic do the job
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Human-induced climate change is an example of
the tragedy of the commons. Economists refer to
climate change as an external cost, which can
cause the market to make poor decisions.
Economic forces also keep the market focused on
short-term profit and cost, disregarding costs
that come far in the future.
International negotiations under the auspices of
the United Nations have not made much progress
so far in actually reducing GHG emissions.
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The ultimate goal of negotiations is to
prevent “dangerous interference” with the
climate system. Danger, in this context,
might be benchmarked in terms of global
temperature, rate of warming, sea-level rise,
peak atmospheric CO2 concentration, or the
total amount of CO2 ever released.
The sooner we begin changing the energy
infrastructure, the cheaper it will be to avoid
dangerous climate change.