Our Changing Atmosphere The Earth’s surface temperature has risen by about 1 deg. F. in the past century Strong evidence suggests that warming is attributable to human activities

Greenhouse Effect Energy from the sun drives the earth’s climate Greenhouse effect maintains livable temperature Problems arise when concentrations increase

http://www.teachersdomain.org/asset/phy03_vid_greenhouse2/ http://www.teachersdomain.org/asset/phy03_vid_co2/ co2 experiment

Our Changing Atmosphere Humans are emitting more greenhouse gases into the atmosphere Cars, trucks, home and business heating/cooling, and power factories(40%) are responsible for about 98% of US carbon dioxide emissions … leads to “Enhanced” Greenhouse Effect…

Since the industrial revolution, greenhouse gases have increased by: Carbon Dioxide 30% Methane 100% Nitrous Oxide 15%

Our Changing Climate Global mean surface temperatures have increased 0.5-1.0 deg F since late 19th century The 20th century’s 10 warmest years have occurred in the last 15 years of the century

420,000 years of Ice core data … support the link between CO2 and Temperature

So what happens to the Earth? Climate is a complex conundrum, with many inter-related factors… Thus we use computer models to make predictions: Rise in sea levels (due to volumetric expansion of warmer water V=VoβΔT, and the melting of land ice in Greenland, Antarctica, glaciers

So what happens to the Earth? Weather changes (difficult to predict): equatorial regions get hotter, Northern hemisphere gets wetter,

Industrialized World… Is 33% of world’s population Uses 80% of world’s total energy

You and I (in the USA): Are 5% of worlds’ population Use 33% of worlds’ total energy

Compared to India: is 15% of world’s population Uses 1% of worlds’ total energy

Compared to India: USA uses more energy just for air conditioning than… India uses for ALL of their energy purposes (5 times more people)

Who’s most responsible? Emissions per American have increased about 3.4% between 1990 and 1997 Most of these emissions, about 82%, are from burning fossil fuels to generate electricity and power our cars Remaining emissions are from methane from wastes in our landfills, raising livestock, natural gas pipelines, and coal

International Effort 1988: IPCC formed (Intergovernmental Panel on Climate Change) Its role is to openly and objectively assess the latest scientific, technical and socio-economic literature produced worldwide relevant to the understanding of the risk of human-induced climate change, to provide the decision-makers and others interested in climate change with an objective source of information about climate change on a comprehensive, objective, open and transparent basis 1992-2007: Kyoto Protocol Treaty(ratifying countries committed to reduce greenhouse gases to 5% below 1990 levels by 2012. 177 countries ratified… not US, Australia)

International Effort 2005 APPCDC (Asia-Pacific Partnership on Clean Development and Climate)… non-treaty agreement amongst the 6 countries that account for 50% of gg emissions… to develop and share technology to reduce global warming Australia, Canada, India, Japan, the People's Republic of China, South Korea, and the United States

Use less energy (and use renewables) Capture CO2 (plant trees!) “average citizens can make valuable contributions by making small lifestyle changes without waiting for governments to act”: Use less energy (and use renewables) ↑ efficiency of electric power production Heat homes with excess power station heat,use hybrid/electric vehicles, Capture CO2 (plant trees!)

What Is Known For Certain Uncertainties What Is Known For Certain Human activities are changing the composition of the atmosphere Carbon Dioxide, Methane, and Nitrous Oxide have increased as a result of human activities Greenhouse gases trap heat in the earth’s atmosphere and tend to warm the planet The key greenhouse gases emitted by human activities remain in the atmosphere for decades to centuries A warming trend of about 1 deg. F has been recorded since the late 19th century

What Is Likely, But Not Certain Uncertainties What Is Likely, But Not Certain What extent has the human-induced accumulation of greenhouse gases are responsible for the global warming trend For instance, scientific understanding of other factors are not know, such as natural climatic variations, changes in the sun’s energy, and the cooling effects of pollutant aerosols is incomplete

What Are The Big Unknowns Uncertainties What Are The Big Unknowns Projecting the impacts to Health, agriculture, water resources, forests, wildlife and coastal areas in regional areas is very difficult Large–scale areas are more suited to global warming computer models Links to Global Warming and El Nino

What Are the Big Unknowns Contd… Uncertainties What Are the Big Unknowns Contd… How much warming will occur? How fast will this warming occur? What are the potential adverse and beneficial effects? These uncertainties will be with us for some time, perhaps decades

Summary There are many unknowns to global warming There are some things that are known however The science points to continued warming Nothing is certain