Yikes.
The chart below is from a TED talk by Dr. Paul MacCready, a few years ago. It really ought to be a wakeup call to anybody who looks at it.
I can't quote the data source(s) he used, but considering his pedigree and credentials, I feel fairly safe in assuming that he got the numbers right.
You see... Dr. MacCready had a PhD in Aeronautical Engineering. He was the guy who designed the Gossamer Condor (first human-powered aircraft), the Gossamer Albatross (First human-powered aircraft to fly the English Channel), and the Gossamer Penguin (First solar powered aircraft). In 2007, his Helios design - with a longer wingspan than a 747, and powered only by sunlight - climbed to a record 96,863 feet. That's higher than any atmospheric aircraft had ever sustained level flight before. That's two MILES higher than the SR-71 can fly, and the SR-71burns jet fuel at the astonishing rate of around 150 gallons PER MINUTE.
Full Bio Here: http://www.avinc.com/about/dr_maccready/bio/
So, what scares me is... this is probably accurate. If current trends hold, around 2050 I figure that it's us, cows, chickens, and robotic cockroaches. Now, to be fair, one can't simply assume that the curves are going to hold the projected paths - hence the question marks. But I sure don't see a lot of effective resistance detering them from doing so.
(Click once for larger, then again for full size.)
