[rbanffy]

I am not sure an economic collapse (although we more or less dodged that bullet last year the shooting continues) would not drag a big part of mankind into abject poverty.

We are seriously looking into a billion people having to move because of lack of water, and a huge disruption on coastal communities - and a huge people displacement because of that. We also have to contemplate a diminishing energy budget per person. And all that in the next 90 years.

The future is a dangerous place, even if some pockets of it may look like The Jetsons.

[berntb]

Why would the world have a lower energy budget?

Solar cells are getting cheaper about as fast as Moore's law. Nuclear power (and if we're really lucky, fusion) can solve most problems.

As usual, the probably real danger for people is... other people.

[rbanffy]

Solar cells are promising, but they cannot solve this problem - at the very least, they can't generate power at night - we would have to rely on either an integrated planetary grid or a huge amount of batteries.

Nuclear has only that much fuel to use. Uranium is non-renewable.

And fusion is yet to prove it can provide enough energy. We need better reactors.

[berntb]

I originally argued against the statement that we will have a "lower energy budget" in 90 years.

In short, I am arguing about developments that will come home to roost in less than a decade -- and disprove your statements. Even if these developments take five times as long, you are still vertigo-inducing wrong...

You are arguing like some sort of inverse Kurzweil. :-)

>>Solar cells are promising

They will never help much where I live. But not many live here.

http://news.bbc.co.uk/2/hi/8386460.stm

People in the highly populated parts of Europe will literally need a reason to not put them on the house -- in just a few years. Then add 80 more years of tech development...

Consider how much energy you'll get from solar cells in a city's total roof area. 1 square meter under the equator is 1 kW. If every person have 10 square meters of solar cells, it should be enough for all energy use (below the polar circle).

(The same goes for energy storage, developed over 90 years.)

>>Uranium is non-renewable.

Check up on Thorium reactors (and also on more modern versions of normal reactors, which burns a larger fraction of the fuel).

Then add 90 more years of development...

There is lots of Uranium in the ground. Raise the prices and it will come up.

>>And fusion is yet to prove it can provide enough energy.

We will know about e.g. General Fusion, Polywell and TriAlpha in just a few years.

Realistically, I'd not give that large chance for the individual projects (10%? 20%?). But I'd be surprised if nothing like that comes along in 90 years. Just consider space based solar, with the next-next-next-next generation of super cheap launch systems.

[rbanffy]

I originally argued against the statement that we will have a "lower energy budget" in 90 years.

Given increasing population, how much more energy do you expect to be able to use? While true we may be able to increase our energy usage, I doubt most of mankind will be able to use as much as we do.

Also, do you realize how much effort (and energy expenditure) would it be to manufacture 10 square meters for every human being alive? Count 10 billion people - that's 100 billion square meters, not counting replacing damaged solar cells.

Nuclear fission is also a point that could be much improved, but it is pretty much a dead end unless we discover some new laws of physics. Nuclear facilities are horrendously expensive to build and to safely manage. There are safer designs, but how much safe is safe in a world you have to guard nuclear fuel (and waste) and keep if from people who are willing to blow themselves up?

As for fusion, you could add the chances of success if they were completely different approaches, but they are not. Also, giving them even a 10% chance of success is very optimistic.

There is no reason to panic, but there is reason to proceed carefully and think through what we are doing and what we are going to do.

[berntb]

>>Also, do you realize how much effort (and energy expenditure) would it be to manufacture 10 square meters for every human being alive?

Please think before writing.

Even today, much less energy is used making solar cells than they create... For material, the latest thin film is not a heavy weight per square meter... (also a hint, we're not running out of silicon for glass...).

In fact, this would take very little resources compared to what a person need to live.

If you want to make a coherent point, you'd note that my "energy budget" didn't include transportation or industry.

We can apply all the clean energy sources we will have in twenty years, for that.

Note that I'm just arguing known sources in one-two decades, assuming the remaining decades are without developments! And you can't answer even that.

Let us assume space based solar in twenty years... 90? I can't even guess.

http://www.npr.org/templates/story/story.php?storyId=1215313...

Did you have any counter arguments against Thorium reactors? Or you're silent because you lack arguments?

>>100 billion square meters [is a lot of area, sic]

You must be unique on this site to never have thought about how many square meters go into a square km. :-)

10 km X 10 km == 100 million square meters. Enough to give 10 square meter to 10 million people, a BIG city. Go check a map, that area is less than the area of the roofs of such a city...

(Most people will live in cities, it seems.)

Enough of the pre-high school math lesson...

>>As for fusion, you could add the chances of success if they were completely different approaches, but they are not.

I don't think you know what you're talking about.

Please explain how a known success/failure of one of the three projects I mentioned would influence the likelihood of the others? I can honestly not see how you could argue that.

I am sorry, but I wonder if you're a troll. I can't be bothered with the rest.

[rbanffy]

Thorium produced in breeder reactors are object of research for many decades, but very few (if any) commercial examples exist. I remember something out of India, but I am not quite sure. There has been some movement around them in China lately, IIRC, but it must be something on a tech demonstration level or we would all be hearing a lot about it. I believe that when someone pull this off, they will brag about it all over the media.

The General Fusion, TriAlpha and Polywell are all a bit far-fetched. GF's thingie has a couple practical problems, like, for instance, extracting tritium from their liquid lead-lithium mix. There are a lot of problems with liquid-metal heat exchange itself, specially on a scale like the one they propose. Radioactive liquid alkali metal exchangers elevate the NIMBY complains to a whole new level. I would give them a 1%. The TriAlpha approach requires higher temperatures than Hydrogen-Deuterium fusion. I would give it about 0.5% chance of success in the next 100 years. If the conditions the GF machine are to operate can be called extreme, I lack superlatives to name what happens inside a Tri Alpha device. As for Polywell... I am an optimist. I would give them a 5% chance. There are some issues on the geometry of the fields (they had some leaks in the "corners") but I expect them to improve steadily enough for sustained operation.

But we are not aiming at technology demonstrators running sustainable reactions. We are aiming at commercial production on megawatt-scale generators. It's not just rescaling your AutoCAD model, even if you don't consider your whole supply chain.

As for solar, you seriously propose replacing the roofs of every home in the planet with solar panels. I live in an apartment, on a 50's building that's not very tall. There are 40 people living in the same building that has about 200 m2 of roof. That's 4 square meters per person on a not very dense arrangement. It's one of the least dense blocks in my region. Most of my friends live on 1 square-meter of roof per person or less zones (taller, newer buildings). This math will hardly work out. As it is, we have a pretty green energy matrix - mostly hydro. Even our cars run on sugarcane ethanol, but, still, ethanol production takes up a lot of land that could be used to grow food and that may be needed for that if the climate goes south and agriculture takes a hit.

You are more optimistic than I am. Things change, but they change slowly. Unless there is a huge political drive behind this, I don't believe we will see much of it before it's too late.

We need politicians who can focus on periods longer than their terms. I am not sure where to find them.

[Gupie]

The real danger is that most of the world will become unsuitable for agriculture, e.g. the Sahara expanding to Southern Europe, the Mid-West becoming one great dust bowl.

[electromagnetic]

You're joking right? The majority of agriculture in the western world is produced directly because of the Gulf Streams warming effect, look at any agricultural output maps and you'll see North American and European production is squarely centred around where the gulf stream contacts the continent and increases local temperatures. As the global temperature increases vast amounts of land will be moved into the range of arable crops, specifically the two largest countries in the world (Canada and Russia) have very low percentages of arable land due to the vast amount of taiga, as temperatures increase the arable land will increase exponentially. These two countries could easily feed the world at present production densities. [Edit: Canada currently has less than 5% arable land, and presently only uses ~0.6% of all land for agriculture. Russia has about 7% arable land, but only uses ~0.1%. The prairies account for ~80% of Canada's agriculture land, and these very prairies are expected to grow exponentially as temperatures increase]

Incidentally your claim that the Sahara is expanding is quite frankly laughable, when all current evidence has been showing it is presently shrinking due to increased rainfall. Expectations are that if this trend continues it will turn into the 'Green Sahara' of 12,000 years ago. This would turn the Sahara into the biggest pasture land in the entire world . . . that's if you believe the global warming models being used.

[TomCobley]

The worse case is dire.:

"We have the example of the Palaeocene-Eocene Thermal Maximum event 55 million years ago. About the same amount of CO2 was put into the atmosphere as we are putting in and temperatures rocketed by about 5 °C over about 20,000 years. The world became largely desert. The polar regions were tropical and most life on the planet had the time to move north and survive." http://www.newscientist.com/article/mg20126921.500-one-last-...

http://en.wikipedia.org/wiki/Palaeocene-Eocene_Thermal_Maxim...

[rbanffy]

It would be, if the warming were even. Remember - as we increase the energy of the system, the _average_ temperature increases, but so does the range it's in. Cold will be colder, hot will be hotter, rainy will be rainier and windy will be windier.

It's not all roses.

[berntb]

I don't disagree with any of the above, but there is a small problem.

During the state transfer, the climate might change fast (there is some evidence for that happening before), which will (over a few years' time) make farming ... well, problematic.

It might be good for the world/humanity, but it sucks to get caught in the middle.

[electromagnetic]

I agree, the climate can potentially change fast (it could potentially change very slowly, we're guessing at a process we haven't been around for before) which is why the burden will be on governments to monitor changes in arable land and provide incentives for farmers to grow crops in the areas opening up rather than waiting for our existing farmland to become useless.

With proper care and planning we should be able to ride out even the fastest change of climate that nature can throw at us, however I started this sentence 'with proper care' which is certainly not a synonym for the government handling of industry.