1. Climate = the average range of weather conditions (usually defined using roughly 30 years or more of observations) for any region. Each location (e.g. wherever you live) has typical February temperatures, for example. The common phrase for distinguishing climate from weather is "Climate is what you expect, weather is what you get." The typical February temperatures might range between -20 and 40 degrees (Fahrenheit) with a mean temperature of say 23. Any given day might be 10, -15, 30 or any other temperature, however.
2. Climate change = changes in the average weather conditions such that either or both the mean temperature or the expected range of temperatures is altered. Precipitation ranges and averages change too.
3. Climate has changed all throughout Earth's history. Over many thousands of years the planet cycles between cold periods (ice ages) and warm periods similar to now (interglacials). However, the concern now is that the entire planet is experiencing a change in its average climate conditions that is increasingly warmer. Note, while the average temperature is definitely increasing, this doesn't mean that every location is experiencing the same amount of warming.
4. The polemic surrounds the reason why the planet is warming. If the sun were getting brighter, for example it would warm the planet. The sun is not getting brighter, however, so that cannot be the cause. Anthropogenic Global Climate Change just means that we are causing the changes. This occurs through our release of greenhouse gases (primarily Carbon dioxide) through activities like burning fossil fuels (oil, coal, natural gas).
5. Greenhouse gases are just gases that are transparent to sunlight but that are not transparent to longer wavelength heat radiation. The effect is like having an increasingly heavy blanket over the planet. Energy (heat) comes in as sunlight but takes longer to escape much like a coat keeps your heat from escaping your body as fast during a cold winter's day.
6. The problem is that the greenhouse gas effect builds every year and we cannot stop it (no way to take the extra blanket/coat off). Naturally, things would recover but will take hundreds to thousands of years after we stop our fossil fuel emissions. Even if we stopped all emissions today, the planet would warm for at least 200 years.
7. It is a huge problem because of both the magnitude of the change and the speed with which it is occurring. If we stay on the 'Business as usual' path of increasing emissions we will warm the planet by 5-6 C (9-11 F) by the end of the century. That doesn't sound too big but when we are talking about changes for the entire planet it is an immense amount of energy. This is the same average change in temperature as we have experienced from the depths of the last ice age until today. Normally those changes would take a few thousand years to occur, we are managing it in one hundred years.
8. All life on Earth depends upon the climate. Everything is where it is now because it is adapted to the typical climate of that location. We are currently causing climate changes that will force all life to adjust to new conditions but it is not adapted to changes that occur this quickly so no one knows exactly what will occur but estimates are that up to half of all species may not make it (extinction).
9. All of recorded human history since the advent of agriculture and writing has occurred within a narrow temperature band. The difference between the Medieval Warm Period and the Little Ice Age was only 1 C different across the planet (average temperature). We are currently headed into warmer global temperatures than any human or even humanoid has experienced.
10. We are literally changing the planet and all of human society will have to adapt (or die), just like every other species.
If you or anyone else wants to learn more come on over to the Definitive Global Climate Change thread
http://www.peakprosperity.com/forum/def ... 1#comments . All are welcome (skeptics too!) to engage on civil discussion and ask questions that are general or specific in nature.