I think Sustainability is one of those concepts/words which started out as a noble idea.

Who would disagree with conserving resources, re-using resources and making sure we consume less of those resources for which we have no way to renew the supply.

These are common sense.

Unfortunately the word has been purloined by greenies to mean extensive government control of just about anything they don't like.

"Sustainability" is merely a slogan, and usually means very little once you scratch the surface. It can mean whatever the author wants.

Some examples: The sun will run out of hydrogen in a few billion years. It is not sustainable, but many would take the line that it will continue for so long that we can assume it is.
On a daily basis, some would say that solar power is "sustainable". I would say that it is sustainable until sunset.

Our use of fossil fuels is described by some as not sustainable. I would say that what they mean is that it will run out soon, or sooner than the sun at least. It's the peak-oil argument. We may well be consuming fossil fuels faster than they are being replenished, but some consider new techniques to be making currently extractable reserves larger.

Some proponents of geothermal energy appear to believe it is sustainable but it is only as sustainable as the nuclear decays of radioactive elements in the earth. This heat is only produced slowly. Geothermal projects are extracting heat that built up over geological time scales, just like fossil fuels formed over geological time scales. Where extracted, this heat is being consumed faster than it is replenished, just like fossil fuels. It is not sustainable.

We have to be careful of not abandoning the good intention behind these things because of the current-day ham-fisted implementation of them. It's easy in the middle of the debate to start rubbishing the very idea of sustainability, renewable energy, etc. as if they were permanently discredited concepts. They are not.

It is prudent and ethical to avoid being profligate with the finite resources we have, just because it's a damn good idea.

At some point in the future we will have the technology to create whatever we want out of the pure (virtually) infinite sources of atomic energy, but we're some way away from that at the moment, so while we still reply on chemical energy it's wise to be careful with it.

Just because they're stupid doesn't mean the clock isn't right twice a day. The sign of a superior argument is the ability to concede the small truths there are in the opposing argument.

We don't have infinite resources... yet. but as the need arises we will exploit new ways of generating resources or using existing resources in a better way, So yes, I'm in agreement with the general thesis that in the long term we don't have to worry too much about resources because we are a resourceful species and will find ways of overcoming any hurdles.

but...

in the short/medium term, we will run up against shortages of things as supply outstrips current technology. Whilst these shortages are in one way useful and necessary to provoke technological advances to ameliorate them, there is a bit of lag in the system when such shortages can cause economic hardship. Whilst we are developing technologies to move away from chemical energy sources, it makes sense to use what we have sensibly.

TBYJ,
I'm one of those old fashioned people who think that the price mechanism of (relatively) free markets is the best way to match supply and demand, produce innovation, and plan for the future. It is sudden shocks to the system, such as that experienced in the 1970's due to OPEC's oil embargo as a result of war between Israel and Arab nations, that cause economic dislocation. Gradually declining fossil fuel reserves is manageable without state intervention. (Other than to prevent industry cartels and price fixing. But existing anti-trust laws were put in place to do just that).

By contrast, the green approach is dirigiste. They think money is not a good enough measure of anything (though they certainly seem to like it flowing into their bank accounts just as much as anybody else). They proclaim they have a better calculus. This usually involves everybody giving up free choice and doing as they are told by environmentalists who claim to know better but, curiously, generally didn't want to study science, mathematics or economics at school or beyond.

It reminds me of my fathers business trips to Russia when I was a child. He came back with a tale that car owners in Moscow removed their wind-screen wipers and took them into their buildings/homes when they parked their cars. The reason given being that bureaucratic calculations decided that every car made needed only one set of windscreen wipers. So someone who needed replacements would have to steal them from a parked car. That is the world the greens would drag us towards.

"Sustainability" means giving money to things that will sustain the green's need for money.

Sustainability is/was a term used to sneak the concept of 'Green' into Government and Local Government mindsets.Those employed as 'Sustainability Officers' will have terrific Green Credentials, and may even wear appropriate badges to prove it.

Any project or scheme led by, or supported by, a Sustainability Officer, will therefore require a disproportinate amount of financial support, with no quantifiable financial benefit to anyone, apart from the paid professional experts who say passionately, that the benefits will be felt by everyone, long after the professional experts have moved on to supporting the next waste of public money.

Anything can be made sustainable, with sufficient community support. Community support actually means taxpayers, and every Sustainability Officer has been told that taxpayers always have unlimited funds. Sustainabilty Officers may seem very nice, but know nothing about sums, particularly sums involving other people's money.

Any scheme with a strong emphasis on sustainability, in official reports which may include Press Releases, should be treated with the same contempt, that will be shown to anybody asking simple questions about the same scheme's real economics. In this way, offence and disappointment can be minmised for all concerned.

As the earth is warmed by the sun and the sun will eventually disappear (via its various development phases) the earth will die.

It/we are not sustainable.

That's a fair summary, Dung. Saves me having to use the T word.

Dung, I'm afraid the earth (if it's still there) will be consumed in the death-throes of the sun, which will expand to take in a size larger than the orbits of the inner planets. Earth won't be swallowed in this expansion (its orbit will actually get farther away) but it will get caught in the tidal forces of the sun's outer atmosphere at that point, which will strip the crust off and basically vaporise the planet, which will become part of the sun.

If we're still around then, and are feeling a bit sad about this, I'm sure we can remove the earth to a nearby museum system, where we keep all the planets of our ancient history in perpetuity. Or perhaps we'd have already moved it to a slightly more salubrious area of the galaxy long before the sun starts to misbehave.

The fact that the earth has a finite lifespan measured in the billions of years does not mean that the idea of sustainability is moot. it's a clever technical point, but a bit nit-picky, and makes us look a bit silly. We, as a species, can only be concerned about the next couple of centuries, and that is the timespan over which sustainability is a concept. The fact that everything will end billions of years from now doesn't mean we don'[t have to be careful about what we have in the next few centuries.