Dan,
Here are some boring replies (perhaps rather obvious) to your three points:
Is the Earth warming a few degrees bad? Except for those living a foot above sea level, the answer is uncertain at best. Will it help or harm coral reefs? Will it help or hurt fish? Will it increase saltwater marshes, is that good? Will it shrink some desserts, enlarge others? Will winters be milder, will hurricanes be stronger, will less hurricaines reach shore? Will crops grow better? When small segments of the enviorment are considered some iffy predictions can be made. How this would balance out over the entire ecosystem is a mixed bag at best and wether there is an overall benifit or detriment is purely dependent on the priorities of the one doing the judging.
An enormous amount of work has been done on known consequences of warming. Hurricanes will be stronger, more frequent - don't live in Florida. Ice melt & water expansion will raise sea level by 10m or so. Not a big deal but extraordinarily expensive for the many countries whose capital cities are near the water line. And mass-migration from those in low-lying coastal area. Climate will change, extreme events become more common. Insurance will go up.
As for the rest - no-one knows. Also no-one knows whether a large perturbation will take climate from is quasi-stationary goldilocks state of last few thousand years and propel it via positive feedback to a new (probably, given history, less pleasant) regime.
But if you were perched high on top of a complex structure known to be unstable would you choose to keep your movements small?
Fad science- the press reports sensationist predictions of the 'polar ice completely (pratically completly) melting next year'. Didn't happen. Were there any public retractions- apologies by those alarmists? Serious scientists are certainly trying to make sense of an extreamly complex world, but puplic claimes presented as absolute certainity while the reality is of MUCH less certainity, serves no one other than those who seek to gain profit from the predictions.
Well I dislike uninformed popular headlines as much as you. But if you condemn science because it is the subject of such you will not have much science left to hold to (including Polywell!).
The issue about uncertainty is dealt with, at length, in a working group of the IPCC. It is not easy for scientists to communicate with politicians. If your best estimate is that something is 90% likely to happen how do you express that? The wrong words and they say "the scientsists don't know, we will wait till they do".
The issue about AGW being validated or invalidated by a few hot or cold years is ironic. the climatologists know all too well how chaotic variations on time scales of years and decades make short-term climate prediction impossible. The AGW science rests on models validated at many levels (cross-validated wherever possible) using histric data over geological timescales as well as more recent time series. The issue of whether these models are skillful or not must, to any thinking person, obviously be very complex. And not done justice by partial reporting on blogs with a political agenda. How do you lead a politician (or the readers of this site, even) through that. Do I need to emulate Simon and say you must have an IQ of >140 to understand it? If so, what do we do with all those who cannot.
Will the Earth warm up, will another Ice Age come, will a killer asteroid hit the Earth? There is high confidence that all of these will happen, possibly many times. Eventially, the Earth will be essetially destroyed by the Sun, and given enough time it could eventualy (befor the Sun fries the Earth)be desimated (life at least- the rocks won't care) by a nearby supernova explosion. The question is what can or should we do about it?
The hysteria about global warming, and the seeming refusel to admit uncertainity, combined with the dire predictions of catrastophy for all is what annoys me. But, despite the annoyiance, it seems that this is how humans gets things done. At least in some countries, along with the excesses, there have been real benifits in terms of water pollution, air pollution, erosion, deforestation, etc, etc.
earth warm up - already happenned, how fast it continues will have big effect on our children.
ice age come - possibly not for millions of years, if we move to new higher temperature regime. But sudden instabilities have characterised earth climate history other than last 10K years, and we seem determined to destory the current quasi-equilibrium so who can tell?
killer asteroid hit the earth? Probabilities well understood and expected time to strike is v long (100K years + I think). Though it depends on what you define as killer. So this is a very small risk to our children (or their children).
Finally - on refusal to admit uncertainty - it is rather the reverse. The one thing we are certian of is that putting masive quantities of fossilised carbon in the atmosphere puts us into an unprecedented (in terms of speed of change) regime. Earth has not been like this for milions of years, at which time climate was quite different. And it (the CO2) is not easy to reverse. So there is lots of uncertainty. While lives are uncertain, we do not normally gamble on quite such a global scale. Previous environmental catastrophes (history is littered with them) have been geographically local. Civilisation has continued, somewhere.
This one is truly global.