Sources of Feed back Positive Negative 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 Clouds Ice albedo Arctic methane release 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 ice-more 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 diatoms-diatoms 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 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 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 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.