What is the greenhouse effect?

What is the worst thing that could happen due to the greenhouse effect?

• I know that the greenhouse effect causes the temperature of the earth to increase due to an increased amount of gasses in the atmosphere. However, I want to know why this is such a bad thing, because most websites aimed at reducing carboon footprints aren't very persuasive; they just tell people how to reduce their carboon footprint. Could it have a serious adverse effect on our farming industries? What would happen if the ice caps in the northern hemisphere were to melt?

• Answer:

  this is a complex question because the earths climate cycles dramatically anyway. For example there was a well documented mini-ice age in the middle ages in Europe when the level of CO2 in the atmosphere was normal.. The main problem with a climate shift is that things change. This can be positive or negative. eg.. one species of penguin that breeds on ice flows at the poles is reducing greatly in numbers, however at the same time another species that is more land based is increasing in numbers. While there are dire predictions of doom from a high CO2 level, it should be remembered that the main source of CO2 is oil. Oil is the residue of huge forests that once covered the earth. At that time, the earth was very different, in fact there were forests where there are deserts and oceans now. Much more of the land surface was habitable. Ironically, the burning of the oil is reverting the earth to a condition where tundra's and other frozen parts have plant growth now. In fact the very phrase "greenhouse" gives a good idea of what the earth would be like when warmer. Generally a garden greenhouse means a huge increase in food production. On the negative side, there may be increased wind velocity at the equator with stronger cyclone activity. The predictions are many, but the main problem is still change. It costs money to make changes. In the end climate change will cost money. The time frame is quite long with modeling of climate change however, so these changes can be absorbed over time as long as governments act appropriately. So far they seem to be acting appropriately