One of the impacts is increased humidity and heat retention in the atmosphere (warmer air holds more water, water holds heat well), with that higher humidity an

One of the impacts is increased humidity and heat retention in the atmosphere (warmer air holds more water, water holds heat well), with that higher humidity and energy level translating into more severe storms. At this point I'd be very leery of purchasing anything in areas traditionally considered to be in "100 year flood plains" because those hundred years were measured over very different climate conditions and these days it seems like those 1% floods have become more like 10% floods. One way of visualizing the impact of warming is by thinking of it like a speaker system. If you turn up the volume (adding more energy), does the average position of the speaker cone itself change much? Or is it just the extremes that change? Part of the concern with climate change is similar to that - the baseline temperature is changing upwards in amounts that don't sound that scary (really, what's the big deal about a degree or two?), but what's really going to do the most immediately noticeable damage is going to be the increased dynamic range which may include temporary instances of extreme cold (e.g. Siberia right now) or extreme heat. Another concern though it breaks the analogy a bit, is whether there's a point at which a peak is such that it causes a permanent change to the whole system. In a speaker analogy, that's a blown speaker (torn cone, coil separation, etc.). In climate change/global warming, that may be thawing methane clathrates undersea (methane locked in the crystalline lattice of ice) or other underground methane reservoirs (e.g. in permafrost) thawing and injecting a temporary massive amount of methane into the atmosphere similar to what happens with CO2 in exploding lakes (which accumulate CO2 as carbonic acid until some event triggers a mass release). That shock of methane will be temporary since methane breaks down relatively quickly, but it's also a very potent greenhouse gas and even a geologically-quick few years of ongoing release may trigger massive changes in a relatively short time - changes that won't go backwards even after the methane degrades, and changes that will trigger massive political instability while they're going on. Another possible tipping point might be Greenland's ice sheets - melt on them has been accellerating in recent years, and while the sheet is generally more than a mile thick and would take a long time to melt, it doesn't have to all melt to be a problem. In fact, if it all melted, the average sea level change around the world would be somewhere around 20 feet. (edit: By the way, my reference to a methane "shock" was deliberate - if that happens, the impact may be disturbingly similar to the effect of a chlorine "pool shock" that kills off things in the pool then reverts back to a normal chlorine level as the chlorine breaks down into harmless forms.)