Presentation on theme: "Physics Behind Global Warming Stefan-Boltzmann Law total heat/energy emitted from a surface is proportional to the fourth power of its absolute temperature."— Presentation transcript:
Physics Behind Global Warming Stefan-Boltzmann Law total heat/energy emitted from a surface is proportional to the fourth power of its absolute temperature. (Applies to black bodies). Earth is receiving more energy than it is emitting. From Sun to Earth: Energy flux at the sun’s surface = 63 x 10^6 W/m^2 (LOTS OF ENERGY) Energy flux drops as it travels the square distance from the radiating body. = 1360 W/m^2. Converted into heat then radiated (electromagnetic waves).
Physics…Continued Clouds play a large role when determining how much solar radiation the earth will absorb. Cloud albedo ranges from 0 - 0.8 percent. Earth’s average albedo is 0.3 0.3 of the radiated heat is being reflected, while the other 0.7 is being absorbed. Incoming radiation flux < out going = increase in temperature. Eventually a radiation equilibrium / balance should be reached.
Physics Continued: Earths average temp is -18°C. The average temp we experience is 15°C --> Greenhouses. The many compositions that make up the atmosphere have different absorption levels. Water vapor & CO2 (most common greenhouse gases) = very absorptive. Radiation that earth emits cannot escape freely. Gases warm = emit heat upwards & downwards. Like a blanket. This causes the earth to warm & has many implications (rising sea level, etc). Ice = high albedo, keeps melting = very absorptive Earth. Oceans low albedo = warming = water vapor = vicious cycle. Argument: this is just a part of Earth’s natural cycle.
Biology (The aspects we see in everyday life): Earth’s Natural Cycles: Before man there have been constant cycles of warming and cooling periods. Every 100,000 years, the planet appears to be alternating between these two climates. Many believe that this justifies our present global heating It is apart of a natural cycle. Counter Argument: Humans have exaggerated this cycle.
Biology: Continued The CO2 in our Oceans Oceans store CO2 in the form of bicarbonate and carbonate compounds. Balloon Experiment Did we put CO2 in our atmosphere? The heating of Earth may be releasing CO2 from Earth’s oceans. 88 tons of CO2 is released from our oceans yearly.
Biology Continued Our Fault? Burning of fossil fuels and coal is the #1 way humans contribute to Earth’s CO2 level. Industrialization & New Technology Scientists believe in order to combat global warming, people must control the use of fossil fuels. Deforestation = less CO2 being converted into oxygen. Source of Greenhouse Gases.
Biology Continued The Effects of Global Warming Intimidates Our Ecosystems Effect 1: Disease Spreads When countries warm up, disease carrying insects migrate to the warmer regions. Scientists blame this for the persistence of Malaria. Effect 2: Strong Storms As the ocean's temperature rises, the probability of hurricanes rises. Effect 3: Polar Ice Caps Melt Ice Cube Lab Sea levels can rise by 230 feet if the ice caps melt Lower the salinity (saltiness) of the ocean waters. Oceans become uninhabitable to salt water fish. Ocean currents will also be knocked out of balance Effect 4: Coral reefs Due to warming of the oceans, many coral reefs have been destroyed. Coral reefs = major habitat for many marine species. Fish diversity has dropped significantly in many areas.
Chemistry Aspects of Climate Change Oceans surface water acidity has increased. As oceans continue to absorb CO2, pH level will drop. Glaciers are melting. pH experiment.
Man-made vs. Natural Natural Causes: Volcanic eruptions: emit CO2 Solar cycles and cosmic rays: responsible for more than 14%? Water vapor: Water vapor is produced as feedback of increased CO2 emissions. Man-made Causes: Driving your car air conditioning or heat Eating food that is out of season and shipped.
It is not Man-made: Water Vapor makes up most of Earth’s greenhouse gases. 99% natrual Humans only contribute by 0.001%
More Graphs Shows how the amount of other gases in small compared to the 95% of water vapor. The overall Co2 amount is 3.618%, and is not exaggerated like the 1 st graph.
It is not Natural: we cannot neglect the 65% of miscellaneous gases
Carbon Dioxide: 72% of gases produced in greenhouses are C02
Group Reflection: Conflicting Ideas Hard to keep Communication Far, time. Working on own vs Working together Hard Topic = Lack of Experiments