The greenhouse effect is the idea that that average temperature of the earth is increasing due to human activity, or more specifically, due to the release of gasses that trap the energy of the sun inside the earths atmosphere. Live Science links to a NASA website that says as much. http://www.livescience.com/37743-greenhouse-effect.html
What does this mean for humanity? The answer is not really clear. We can deduce that all the ice caps would melt eventually, causing the shoreline’s to raise a few hundred feet.. But since there is enough habitable land to sustain the people who would be affected after all the ice has melted, I can’t hold the view that it is really a cause for concern. Additionally, the temperature of the earth will rise meaning that the places that are hot will get hotter and the places that are cold will get warmer.. Still though, I don’t see why this is a problem. Species have adapted to their environments for hundreds of millennia and we can assume that they will continue to do so.. So the only option left is a worst case scenario in which the planet becomes so hot that it is unlivable. At this point, the damage is already done though.. The amount of industrial reduction needed to avoid this catastrophe would effectively return us to the stone age, and cost an incalculable amount of money. Realistically, it would be better for us to prepare for Global Warming than to keep harping on about trying to avoid what is seemingly inevitable.