I find the debate of nuclear energy and global warming a pertinent one, but one that misses some of the bigger questions (what, you ask, could be bigger than global warming?).

Some might laugh at it as "funny science", but I refer here to peak oil. Estimates I've seen put global peak oil at any time between 2000 and 2035 (we may have already hit it, but won't know until later). From that point on production will decline and prices will rise, supply will outright fail to meet demand at some point on the other side of the peak.

The question then, is what can we do if we take petroleum and natural gas out of the picture in terms of maintaining our current lifestyles? (We may argue over when oil & gas will become unviable, but not whether they will as they are finite resources that we are consuming at an alarming rate. Assuming we could even maintain our current level of consumption BP data suggests we'd drain every known drop of petrol within 40 years - of course the last half of those drops gets harder to get, and prices go up, making it unviable for things like commuting and producing garden gnomes in China to sell in the US)

The only outright replacement for oil/gas is nuclear/hydrogen. There is no hydrogen economy without nuclear, because nothing can meet the energy needs to produce hydrogen on the scale we would need to continue uninterrupted besides nuclear.

Of course we then invest $$$$ in nuclear, only to find out that... guess what? Uranium is a limited, non-renewable resource as well. There may be enough in the ground for 100 years, 200years, or maybe even more. The question is, are we willing to build the 400 nuclear power plants necessary to meet current consumption, and the hydrogen infrastructure associated with hydrogen economies, as a "transition" strategy?

The intelligent response to our fuel crisis is to restructure everything we know about modern life, and stop our outrageously wasteful consumption patterns. Local production for local consumption. Conservation tactics in everything from architecture to cooking to how we plan our communities.

I know nobody has the fortitude to do this, sadly. No politician (Jimmy Carter aside) is up to the task of telling people they will no longer be able to drive their cars and will need to return to rail.

My hope is that petroleum becomes unviable in time to prevent a climate change catastrophe. The question of nuclear I hope will be solved by the immediacy of peak oil. If the crisis ensues in time, there will not be the possibility of building 400 (or 10,000, or whatever is needed) nuclear plants before the effects are felt and economies restructure themselves.

Peak oil theory is not strictly relevant to the debate on electricity, although it clearly is appropriate to any broader energy discussion. Some of the claims of peak oil theorists, in particular regarding mature fields in Saudi Arabia, have been effectively rebutted by oil producers, but it is certainly likely that oil production will hit a plateau within the next 20 years or so: world production is now about 85m b/d, and it is difficult to see sustained output over more that 100m b/d based on known or likely reserves.

When it comes to electricity generation, there is no suggestion of "peak coal" being a constraint, and the prospects for sustained increases in gas production are better than those for oil.

However, if we put all these factors together--doubts about oil capacity, serious concerns about the effects of using more gas and coal, and awareness of the dangers and limits of nuclear power--the conclusion that we must make radical changes to the whole pattern of our energy consumption is persuasive.

The problem with peak oil is estimating the time it will occur, but that it WILL indeed occur should not be an issue. If it happens in 1 year or 20 years, it makes no serious difference other than in the amount of time we have to plan our transition strategy. My understanding is that the US Geological Survey in 2000 estimated global oil p90 reserves at 2 trillion barrels, p50 reserves make it something like 2.7 trillion (the equivalent of discovering another ghwar field). we know from publicly available data that we've used ~1 trillion barrels. That puts us right on the cusp of peak oil one way or another.

Nuclear is practically unavoidable. The combined energy production of solar/wind/hydro and even thermal depolymerization do not really come close to producing energy to meet our current consumption needs. We would need a serious reduction in energy use to rely on these and avoid coal/nuclear.

The problem with coal is strictly global warming. There is still enough coal out there to easily last us at current energy consumption rates for some 200 years or more. The problem is we can't afford to pump the air full of those carbon emissions without dealing with the 7 trillion dollar question of global warming. Now there is interest in "carbon sequestering" but it sounds to me like a lot of fantasizing. I've heard of developments in chimneys that improve emissions and efficiency, but I doubt they make coal viable enough as an energy source that wont kill us through GW.

Which leaves us with 2 options: vast reduction and rescaling, or nuclear.

The only reason I resist nuclear is because Uranium is a fossil fuel as well, and the amount of infrastructure needed to make a nuclear/hydrogen economy functional seems a bit foolish for something that's only a transition strategy. But then I doubt many care to think 100 or 200 years into the future.

The main question on my mind is how many nuclear plants are needed to meet our energy demand (which I would call the gap between what we can reasonably get from renewable sources and current consumption) and how quickly they can be built and integrated into a grid.

Technology wise, the R&D should be focused on how to handle the waste. I seem to recall reading something about a technique to crystallize or compress the waste, such that all the nuclear waste produced so far in the world could be kept in a facility the size of a school gymnasium. That again could be some fuzzy science, but if it was possible to solve the waste issue, then really its just a question of investing in it knowing that uranium will peak as well sometime in the future, and at that point we will be out of "gifts" from the earth to sustain us.

I find it interesting to see the media and governmental emphasis on Global Warming, Peak Oil and alternative fuel sources. In my opinion the underlying issue ( as mentioned above) is much larger. We live in a society where more is better and desired. and in the same breath we speak of sustainable development. Let's face it we have a finite resource potential (at least on this planet) and the earth has a finite capacity for our influence. Thus if we continue to proceed with the paradigm of growth we will face the consequences. Arguably we can slow down the effects, global warming for example, but without changing the paradigm no amount of science or engineering is going to prevent the inevitable. I suspect that in fact as more third world countries industrialize (China and India for example)the rate of Natures response to our influence with increase exponentially.

rohall - the peak oil issue really goes hand in hand with consumption/demand. Peak oil tells you that we are going to run out of fuel, and studies show that the only serious replacement is nuclear (which can be used to separate hydrogen from water as well), but nuclear runs on uranium - also a fossil fuel, so ultimately we just can't go on as we are. The energy is just not there for us to keep living as we do.

In "Out of Gas" by David Goodstein (http://en.wikipedia.org/wiki/David_Goodstein), professer of physics and applied physics at Caltech, he has some interesting figures:

"known reserves [of uraniam] are estimated to be enough to supply all of Earth's energy needs - at the current rate of energy consumption - for a period of only 5 to 25 years. That estimate ignores the growing world demand for power, as well as the Hubbert's peak effect, which is just as valid for uranium as for oil." (106)

Now we're not looking at nuclear to supply 100% of the world's needs. Renewable sources will contribute, especially hydroelectric which I believe provides something like 25% of energy in the US? Don't have the figure handy. But lets say Nuclear needs to pick up about 50% of the energy we consume... its still 10-50 years at best based on current reserves.

Unfortunately estimating uranium reserves is a fuzzy exercise, not as well refined even as estimating oil and gas reserves, so we could be off by a lot. Maybe there's a lot more uranium out there than we currently know about, which would extend the life of nuclear power. I would wager however that it would take a very exceptional set of circumstances for uranium reserves to meet even half of our energy needs for more than a century.

Which returns me to the original dillemma - do we really want to invest time, energy, and capital in building a nuclear/hydrogen economy knowing right now that its lifespan will only be 50-100 years, at which point we will be out of freebies from the earth, unless we turn to coal (which people probably would, forgetting by then about the global warming threat of 2000-2010).