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Sources of Feed back
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Water vapor
Clouds
Ice albedo
Arctic methane release
Reduced carbon dioxide
absorption in the oceans
• Negative
– Lapse rate
Negative feedback
• Lapse Rate
• Increased heating means increased IR
emission
• Global warming reduces the rate of
Temperature decrease with height, which
means more long wavelength radiation will be
emitted by the upper atmosphere
• This will weaken the greenhouse effect
Positive feedback
• Water vapor
– Warming increases the amount of water vapor in the atmosphere,
which increases the warming since water vapor is also a greenhouse
gas
• Clouds
– Act as a blanket, reflect IR radiation downward toward the surface
• Ice albedo
– Melting ice reveals land and water, both reflect less light than icemore warmth is absorbed increasing warming
• Arctic methane release
– Warming releases sources of carbon dioxide
• Reduce carbon dioxide absorption in oceans
– Warm waters favor the growth of plankton rather than diatomsdiatoms are more efficient carbon dioxide absorbers
Global dimming
• An effect that has been counteracting some of
global warming from about 1960 forward
• Aerosols produced by volcanoes and
pollutants such as sulfur dioxide reflect
incoming sunlight
• Soot –suspended in the atmosphere, it can
absorb solar radiation and heat the
atmosphere, but cool the surface
What are we seeing:
• Besides the increases in Temperature:
– World’s glaciers are melting
– Arctic sea ice is reducing in both extent ( 9% reduction in area per
decade) and thickness (15-40% in thickness in the last 30 years)
– Ocean levels are rising-both due to melting of Antarctic ice and
thermal expansion of sea water
– Longer growing seasons
– Thawing of permafrost in Alaska
– Coral reef bleaching-whitening of reefs due to increased temperature
– Earlier plant flowering
– Earlier bird arrivals
– Shifting of animal ranges poleward
– More frequent EL Nino-warming of the Pacific ocean surface
temperatures-causes changes in local weather patterns
Global warming-the debate
• The fact that the Earth is warming is not a
matter of debate, the evidence is clear
• The fact that global carbon dioxide levels have
increased is also clear
• The debate centers around how much of it is
caused by human involvement vs a natural
cycle
• Think about it in terms of the steps in the
scientific method:
Global warming in the context of the
scientific method
• Observations-Earth’s temperature is warming
• Hypothesis-due to a man-made increase in green house
gases
• Testing the hypothesis-many scientists hold different views
and interpret data differently, but the consensus is that it is
due to increases in greenhouse gasses from man made
sources.
• Until the data is incontrovertible, there will always be
naysayers. That’s ok, they keep us honest and push the
method forward-as long as they are within the realm of the
scientific method
• Lots of examples like this in modern science (evolution, big
bang, cosmological interpretations of galaxy redshifts)
Dissenting opinions
• American Association of Petroleum Geologists was the
last scientific body to acknowledge human influence on
climate change
• Individual scientists fall into 5 categories:
– Believe global warming is not occurring or has ceased
– Believe accuracy of IPCC climate projections is
questionable
– Believe global warming is primarily caused by natural
processes
– Believe cause of global warming is unknown
– Believe global warming will benefit human society
• In the end, only time will tell.
Prognosis
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How do we know what is going to happen?
We don’t , but it can be predicted
We call these global climate models
Based on physics (fluid dynamics and radiative
transfer, for eg.)
• Different models consider different effects, have
different inputs and give a range of results
• Model validity is verified by using them to predict
past and current climate conditions
• No, they are not perfect
Projections
Prognosis
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Sea level rise of up to 1 foot
Reductions in ozone layer
More intense, less frequent hurricanes
Ocean ph and oxygen level reduced
Spread of diseases including malaria, Lyme
disease, cholera and bubonic plague
• Extinctions of plant an animal species
• Population growth due to less deaths from cold
weather
• Changes in rainfall patterns
What are we doing about it
• Kyoto Protocol
– International environmental treaty to achieve stabilization of
greenhouse gas concentrations in the atmosphere at a level that
would prevent man-made interference with the climate
• establishes legally binding commitments for the reduction of four
greenhouse gases (carbon dioxide, methane, nitrous oxide, sulphur
hexafluoride), and two groups of gases (hydrofluorocarbons and
perfluorocarbons) produced by (industrialized) nations,
• general commitments for all member countries.
• Did not impose limitations on developing countries (such as China)
• initially adopted for use on 11 December 1997 in Kyoto, Japan
• entered into force on 16 February 2005.
• Signed but not ratified by the US
Kyoto
• industrialized countries agreed to reduce their
collective GHG emissions by 5.2% compared
to the year 1990.
• National limitations range from 8% reductions
for the European Union and some others to
7% for the United States, 6% for Japan, and
0% for Russia.
• The treaty permitted GHG emission increases
of 8% for Australia and 10% for Iceland.
US position
• US signed in 1998, but this was symbolic-treaty is not binding until ratified.
– Yet the US is the largest per capita emitter of carbon dioxide
• Prior to Kyoto, (though with a knowledge of what it said) the US Senate
passed a resolution that stated “stated the sense of the Senate was that
the United States should not be a signatory to any protocol that did not
include binding targets and timetables for developing nations as well as
industrialized nations or "would result in serious harm to the economy of
the United States””
• Main concern is the economic losses associated with instituting the caps
on carbon emission
• Neither the Clinton nor Bush administration submitted the treaty for
ratification
• Obama Administration’s position is that the treaty is about to end, there is
no point in ratifying it (it has a little less than 3 years left)
• States and cities have adopted initiatives to cap carbon emissions on their
own, based at least in part on Kyoto.
Reasons for opposition
• Global socialism-a scheme to transfer wealth
to third world countries and or slow the
growth of the worlds industrialized
democracies
• Doesn’t go far enough to curb GHG emissions
• Costs outweigh benefits
• Using a single base year (1990) may result in
inequities in the caps
Next step-beyond Kyoto
• Meeting in Copenhagen in December 2009
• The Copenhagen Accord was drafted by the US, China, India, Brazil
and South Africa on December 18, and judged a "meaningful
agreement" by the United States government.
• It was "taken note of", but not "adopted", in a debate of all the
participating countries the next day, and it was not passed
unanimously.
• The document recognized that climate change is one of the greatest
challenges of the present day and that actions should be taken to
keep any temperature increases to below 2°C.
• The document is not legally binding and does not contain any
legally binding commitments for reducing CO2 emissions.
• Many countries and non-governmental organizations were opposed
to this agreement, but, as of January 4, 2010, 138 countries have
signed the agreement.
Cap and Trade
• An environmental policy that caps emissions while giving source
flexibility in how they comply with those caps-uses economic
incentives to get compliance
• A limit or cap on the amount of a pollutant that can be emitted is
set. Companies or other groups are issued emission permits and are
required to hold an equivalent number of allowances (or credits)
which represent the right to emit a specific amount. The total
amount of allowances and credits cannot exceed the cap, limiting
total emissions to that level. Companies that need to increase their
emission allowance must buy credits from those who pollute less
called a trade. In effect, the buyer is paying a charge for polluting,
while the seller is being rewarded for having reduced emissions by
more than was needed. Thus, in theory, those who can reduce
emissions most cheaply will do so, achieving the pollution reduction
at the lowest cost to society.
• Allowed under Kyoto for nations to sell their credits.
American Clean Energy and Security
Act
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Also known as the Waxman-Markey Act
Proposes a cap and trade system for Greenhouse Gas emissions
Requires electric utilities to meet 20% of their electricity demand through renewable energy sources and energy
efficiency by 2020.
Invests in new clean energy technologies and energy efficiency, including renewable energy, carbon capture and
sequestration, electric and other advanced technology vehicles, and basic scientific research and development.
Protects consumers from energy price increases. According to estimates from the Environmental Protection
Agency, the reductions in carbon pollution required by the legislation will cost American families less than a
postage stamp per day.
The bill requires a 17-percent emissions reduction from 2005 levels by 2020; this would reduce United States'
emissions by about 80 percent by 2050. Complementary measures in the legislation, such as investments in
preventing tropical deforestation, will achieve significant additional reductions in carbon emissions.
It includes a renewable electricity standard) requiring each electricity provider who supplies over 4 million MWh
to produce 20 percent of its electricity from renewable by 2020. There is a provision whereby 5% of this standard
can be met through energy efficiency savings, as well as an additional 3% with certification of the Governor of the
state in which the provider operates.
It provides for modernization of the electrical grid
It provides for expanded production of electric vehicles
It mandates significant increases in energy efficiency in buildings, home appliances, and electricity generation.
Climategate
• Also known as the Climate Research Unit e-mail
controversy
• Internet leak of thousands of emails and other
documents from the University of East Anglia's
Climatic Research Unit (CRU).
• emails and documents were obtained through
the hacking of a server.
• hacker had filtered them using keywords,
including "Yamal", "tree rings", and "Phil Jones",
so that these names appear in many of the
documents
Climategate-what was stolen
• more than 1,000 emails, 2,000 documents, as well as
commented source code, pertaining to climate change
research covering a period from 1996 until 2009.
• The vast majority of the emails related to four
climatologists: Phil Jones, the head of the CRU; Michael
E. Mann of Pennsylvania State University (PSU), one of
the originators of the graph of temperature trends
dubbed the "hockey stick graph”; Tim Osborn, a
climate modeller; and Mike Hulme, director of the
Tyndall Centre for Climate Change Research.
• The four were either recipients or senders of all but 66
of the 1,073 emails,
Climategate-allegations
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Allegations that the hacked emails showed evidence that climate scientists manipulated data.
A few other commentators said that the evidence supported claims that dissenting scientific
papers had been suppressed.
The Wall Street Journal reported the emails revealed apparent efforts to ensure the IPCC include
their own views and exclude others and to withhold scientific data.
Reason reported that the CRU evidently plotted to remove journal editors with whom they
disagreed and suppress the publication of articles that they disliked.[
The ICO made a statement that the emails revealed that freedom of information requests were 'not
dealt with as they should have been under the legislation' but that they could not prosecute due to
statue of limitations.
Academics and climate change researchers said that nothing in the emails proved wrongdoing, and
dismissed the allegations.
Independent reviews by FactCheck and the Associated Press said that the emails did not affect
evidence that man made global warming is a real threat, and said that emails were being
misrepresented to support unfounded claims of scientific misconduct. They also concluded that
there were disturbing suggestions that scientists had avoided sharing scientific data with skeptical
critics.
Climategate-understanding the trick
• Many commentators quoted one email referring to a "trick" used in
Mann's graph to deal with the well-known tree ring divergence problem to
"hide the decline" that particular proxy showed for modern temperatures
after 1950, when measured temperatures were rising.
• These two phrases were taken out of context by climate change skeptics
including Senator Jim Inhofe and former Governor of Alaska Sarah Palin as
though they referred to a decline in measured global temperatures, even
though they were written when temperatures were at a record high.
• In their inquiry into allegations of research misconduct, Penn State
reviewers found ”the so-called 'trick' was nothing more than a statistical
method used to bring two or more different kinds of data sets together in
a legitimate fashion by a technique that has been reviewed by a broad
array of peers in the field.
• The Parliament of the United Kingdom select committee inquiry
concluded that "[Trick] appears to be a colloquialism for a "neat" method
of handling data," and "[hide the decline] was a shorthand for the practice
of discarding data known to be erroneous”.