When will the oil run out?

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So when will the oil run out? There were several questions like this - I rolled them into one big answer for archival purposes.

Why doesn't America use it's own oil resources?

According to the Wikipedia articles: 'Texas' and 'Oil reserves': The known petroleum deposits of Texas are about 8 billion barrels, which makes up approximately one-third of the known U. S. supply. Texas has 4.6 billion barrels of proven crude oil reserves. ('known' means you know it's there, 'proven' means that you know you can pump it out) - so out of a world reserve of perhaps ('proven') 1.2 trillion barrels ('known') 4.8 trillion. So Texas accounts for about a half to a tenth of of one percent depending on how optimistic you are. The article on 'California' doesn't quote figures - but I imagine it's less - but if Texas' supply is one third of the total for the USA, then with all of the states put together, there is 24 billion (known) and 14 billion (proven). The world is using oil at a rate of 84 million barrels per day of which the USA consumes about 20 million per day (and produces only 8 million). So, from this we may deduce that if oil imports ceased tomorrow then all of the USA reserves put together might maybe keep the country running for two years before running dry using 'proven' numbers or close to four years if we could exploit all of the oil shales and other inefficient sources. However, that's not going to happen because nobody in their right mind would put in all of that investment into enough plant capacity to pump at that rate if it's only going to operate for a couple of years then run dry. At 14 billion barrels, the US reserves are a drop in the bucket compared to: Abu Dhabi (92 billion), Iran (132 billion), Iraq (115 billion), Kuwait (99 billion), Saudi Arabia (259 billion), Venezuela (78 billion).

But these days, we shouldn't be concerned about running out of oil - the problem is what we'll have done to the atmosphere long before we run out.

If the USA just used the reserves within their own borders, could we get rid of this terrible dependence on foreign oil?

The answer is flat out "NO!" - not unless the US could halve consumption every year from now until eternity. If we agree that there are two years worth of reserves at present consumption rates then here is the 'never running out' model: Year one, consume half of the reserves - but then halve our consumption(!). Year two, half as much oil left - but with half the consumption rate, that's still 2 years worth...and so on, halving consumption and halving the reserves every year - forever). But there is no imaginable way to do that...this year, replace every single 20mpg car with a 40mpg hybrid...next year...um...we don't have 80mpg cars so halve the number of miles driven(!!)...and the next year...um...no clue. So the US is stuck with foreign oil dependancy forever - which is clearly problematic when you look at the list of names of countries with substantial oil reserves and the current political situation.

But suppose you treat this as a global problem then with (say) 1.2 trillion barrels left in the ground, but with 80 million barrels per day being consumed. We have about a 500 year world-wide supply at present consumption rates. So to avoid running out, we'd only have to halve consumption every 250 years - which is easily do-able. However, I doubt any reasonable atmospheric scientist would agree that we could continue to burn oil at the present rate for even 20 years - let alone 250. Even if those figures are inflated by a factor of 4 (which I doubt because the numbers were higher than that before the OPEC reserves rule came into being). If we had only 300 billion barrels in the ground, we'd still have ~60 years to halve our oil consumption - which is still vastly too long to save the planet from global warming. That's why we have to be more concerned about the atmosphere than with running out.

Will the world run out?

Following on from the calculations from the previous question - the answer is that if we were to carry on consuming it at the present rate, it would run out in about 500 to 600 years. However, if we actually did that, the CO2 levels in the atmosphere would be far beyond "mere" global warming problems - they'd be at a point where humans (and most animals) couldn't breathe. However, the assumption that we'll carry on using it at present levels is flawed. I don't think that running out is a practical proposition. Even if we somehow managed to 'sequester' the CO2, we would only have to halve our consumption every 250 years in order to make the stuff last forever. Another issue is that these numbers for oil reserves are always accompanied by a caveat that says "economically retrievable" - in other words, the only things the oil companies care about is the stuff they can dig up for less than they can sell it for. There are reserves of stuff like "oil shale" that contain a lot of oil - but which are so expensive to dig up and refine that it's not worth doing it. If the oil were ever seriously likely to run out, then the price would go through the roof and suddenly oil shale (or whatever) would be worth exploiting and our reserves would increase (although the price would still be astronomical by today's standards). However, we must stress that with what we know about global warming, it's all completely irrelevent. We must not ever come even close to running out - because even a tenth of that amount of oil - when converted to CO2 - would kill the planet.

The world's oil reserves are 5.7x1022J, and annual oil consumption in 2005 was 1.8x1020J, so this gives a ratio of reserves to consumption of over 300 years.

Can we sequester CO2?

Wikipedia's article on Carbon capture and storage explains that what we're likely to have will remove 80 to 90% of the CO2 from the gasses and consume 10% to 40% more energy. But the biggest problem is what you do with the stuff once you've captured it. Sequestering it into limestone requires 180% more energy - so that isn't going to fly.

If you try to sequester the CO2 without chemically converting it to something else then you've still got to find a place to store millions of tons of something that's a gas at normal temperatures and pressures. That's no easy task. You can't store it underground or underwater because there isn't enough space at normal temperatures and pressures (If you burn a cubic meter of oil or coal - you get a LOT more than a cubic meter of CO2 as a result! So pumping it into disused coal mines and oil wells isn't going to work for very long.)

If you compress the CO2 so it takes up less space (eg storing it as dry ice), then that requires either very high pressure storage or very low temperatures. Either of those technologies will require yet more energy - and worse still, will be vulnerable to long term corrosion and other damage - so you're just building up more trouble for the future.

There is talk of dissolving the stuff into saline aquifers or deep oceans - but those are not permenant solutions (eventually, the CO2 would get out again) and the resulting carbonic acids would likely do untold amounts of damage to the environment. Dealing with radioactive waste from a nuclear power plant is EASY by comparison because so little material is involved. So, no, we aren't going to be doing this if we want to save the planet. We have to cut down our consumption (probably the easiest thing to do in the short term) and switch rapidly over to nuclear and (where possible) wind/solar/tidal power until we figure out how to make fusion reactors that actually work.