Lets look at the facts with proven data or information.
Global Warm is a natural occurrence since the end of the Ice Age. Earth had several glacial periods and the cause is unknown. We are currently in an Ice Age that has progressively getting warmer. The last 50 years a large increase in Co2 levels has been measured. Some infer it's fossil fuel usage. I thinks it's related to massive growth population post WWII and human excessive usage and production of energy.
Based on ice core drilling in Vostok Antartica, CO2 levels flutates periodically the last 400,000 years and the earth's temperate seems to correlate with this. Earths temp seems to vary 10-12C. I don't know where they got that temperature number but the CO2 is measurable. Another gas, Methane, is also highly correlated to earth temperature.
http://www.daycreek.com/dc/images/1999.pdf
- Use of fossil fuels create dust, smog, fine particulates, and CO2 and other green house gases. Greenhouse gases can lead to an increase in temperature of the earth.
Related info - Dust levels seem to increase and corresponds with a dramatic drop in temp, then a gradual rise in Co2 and temp. Possible cause - meteor/ asteroid impact, volcanic activity, nuclear war, or aliens sprinkle fairy dust in the air. What is known CO2 and Temps are correlated
- Glaciers have been receding at an alarming pace in the last 25 years. Result is higher ocean water levels and smaller ice sheets.
-CO2 and Methane reservoirs gas can be trapped in ice waters and lakes in Siberia and Greenland that can have been cover by ice shelf for thousands of years. Melting ice can release this. Lake Nyos in Africa is an example of stored CO2 in a large water body reservoir from surround volcanic moutains.
Interesting Fact - Glaciers covered in black pollution are disappearing faster than uncovered ones. The black layer causes them to absorb more heat in the summer and melt faster. In the EU, they are using sheets and blankets to cover glaciers and preserve them for tourists.
Interesting Fact- Alaska had it's warmest measure summer heat wave.
- Ozone is smaller but that doesn't matter, the Ozone is important in reducing UV rays. The primary cause in thinning the Ozone was aerosols with CFC and HCFC discover by two Nobel Prize winning chemist at UCI. The Montrol Protocol eliminated the use of CFC like R-12 in air conditioners and industrial use by the 90s and now HCFC like R-22. UV rays could increase temperature of the earth but the primary worry was skin cancer. It's still a conspiracy that it was business related and pushed by Dupont to corner the market and use their new copyrighted and company developed refrigerants.