What is the greenhouse effect and how is it related to global climate change?

the greenhouse effect is a phoenomenon that tends to affect those areas with high rate of air pollution. main responsibles of this circumstance are the exhausts’ emissions of hydrocarbons fueled combustion engines, which are rich in CO2. They constitute the “smog” (when mixed with fog and haze <smog = SMoke + fOG>) and the “greenhouse gases" (when mixed with volatile fine particles - such as the PM12). these gases have the characteristics of being quite "heavy", so they hardly tend to disperse in normal weather conditions and they surround and enclose the area they belong to up to the atmosphere, in a "bubble". such “bubble” is the virtual “greenhouse” from which the gases take name. in fact, the Sun's UV rays (the hottest and most hazardous, that are no longer filtered because of the ozone depletion) can trepass the outer side of the "greenhouse's roof" they constitute, and resch the Earth's crust.. but because of the "index of refraction", a physical characteristics of the greenhouse gases, the UV rays then keep "bouncing" between the ground and the "inner roof" causing the other outspoken phenomenon of the "global warming", an increase of the average temperatures of the different areas of the earth, which is able to modify the climate itself of such zones... and all the terrible consequences the future generations will have to face. it's clear I'm quite sensitive about the matter therefore I allow myself adding a small warning: they year 2020 will be the "point of no return", when the global average temperature will increase of 2°C. you think it's an insignificant change? then next time you're in a car with A/C, try to increase or decrease of that amount the thermostat, and experience the huge difference they can make. Imagine at global level what could happen. CHANGE YOUR HABITS NOW AND CHOSE ENVIRONMENTAL RESPECTFUL BEHAVIOURS/PRODUCTS/COMPANIES. It's the only way to guarantee a decent future to our grandchildren. "the earth is not our parents' present, but something we are borrowing from our grandchildren"