The thing is, you and I are no more qualified to speculate on the future than someone from 100 years ago would be qualified to speculate on the Internet. However I can say one thing: if we even make a fraction of the progress in the next 100 years compared to the progress in the last, I don’t think we have anything to worry about when it comes to energy or transportation.
I'd say we are.
We don't expect the speed of light to change for example. Whereas people in the 1800s didn't have any such hard limit (e.g. based on Newtonian theory).
We also have the benefit of hindsight, and can see the rate of technical development (and e.g. that the low hanging fruit were on the late 19th century, increasing on early 20th century, and dropping down after the later half of the 20th century.
>However I can say one thing: if we even make a fraction of the progress in the next 100 years compared to the progress in the last, I don’t think we have anything to worry about when it comes to energy or transportation.
Compared to the progress in the last 100 years, or the last 50 years? Because already the progress in the last 50 years is laughable compared to the progress up until 1970 or so.
E.g. we had electricity, nuclear energy, combustion engine, radio, tv, film, digital imaging, lasers, microwaves, satellites, internet, computers, airplanes, transistors, rockets, radars, and tons of other fundamentals already available by 1960s -- not so much huge progress later on aside from evolutionary stuff.
(Well, we did have the slinky)
shouldn't the internet be considered the greatest achievement yet?
When was the last time a new technology reached commercial success?
Besides we're not talking about mere products here, but core technologies, e.g. inventions. The steam engine, the combustion engine, electricity, the telephone, laser, microwave, satellites, and so on, weren't mere "applications of other technologies" and even less so a mere incremental bump in the way modern internet vs 60s/70s internet is.
Our immediate environment aside from Earth is the vastness of the solar system, in planets totally unsuitable to support us, and with extreme costs to even get us to the nearest one, and with vast expanses of space and radiation to go through to get to the next.
We got humans to the closest rock for a few years, on a huge cost and effort, and with big risks (and some casualties), based on the competition of 2 superpowers. Since then, not only we haven't established any "base", but we haven't even been there for 48+ years (almost half a century)...
And even if by a very slim chance (which people who view technological progress as some kind of boundless Paolo Coelio fairy tale take for granted) we manage to do something in those planets, the next step (some earth like habitable planet elsewhere) is extremely more challenging, and speed of light limits would apply (of course people who view technological progress as some kind of boundless Paolo Coelio fairy tale bypass them with exotic contraptions that have us riding wormholes and what have you...).
And that's if war and climate mayhem doesn't have us concentrate all our efforts here...
Some food for though: don't concentrate on the pedantic details, but the high level arguments:
http://www.antipope.org/charlie/blog-static/2009/11/the_myth...
http://www.antipope.org/charlie/blog-static/2007/06/the_high...