1) You could easily get it. Other people here have been plotting it. If you asked nicely, I'm sure they'd tell you where to find it.
2) a) If I collected 12,000 points by measuring the Arctic extent every 15 minutes from April through July, I would get a very nice trend forecasting a melt-out some time in about November. Would this be accurate? No, because it would not be grounded in physics. The Earth has a yearly cycle which means that naively forecasting a trend is not necessarily a good predictor of the future. There may or may not be cycles in average yearly extent: there are _certainly_ physical factors which you are ignoring that will alter the shape of the trendline for average yearly extent.
2) b) As previously stated, there are many different trendlines you could fit to your 12,000 points, with completely different results. Why have you chosen exponential (or was it quadratic) ahead of Gompertz, say?
3+4) No it isn't, for reasons we're trying to explain to you.
5) Finally something we can agree on!
6) No, you can't. Well, you can say it, but that doesn't make you right, or even plausible.
7) Being revoltingly patronising doesn't exactly help your cause. We all know what an average is.