Not to put to fine a point on it but the future has some challenge in it.

There are several things to try to get a grip on:

1. Global Warming
2. Peak Oil
3. [un]Limited Growth

Where do you want to begin?  Global warming is a good place to start.  There is a rising consensus that burning fossil fuels is a significant contributor to global warming.  I know there are folks who are unconvinced but I have looked at a number of arguments and have noticed a repeating theme among nay sayers:  they just disagree but fail to engage in factual discussion.  They just disagree.  If you are willing to look you can find both sides of the discussion.  I've noticed that they who affirm global warming also respond to the nay sayers in thoughtful detailed ways.  I particularly like the argument that says that people who stand to make money are the ones pushing global warming.  Who stands to win if global warming was not a fact?  Curious.

But here's the deal.  Most (like 50%) of the population lives within 50 miles of the sea.  If we melt the polar ice the sea will rise 200 feet.  So unless we stop global warming (another problem) the sea is going to cover a lot of dry land in the next 100 years.  Yes, it will take a while - but then we reduced the sea ice in 2007 on the North pole by 1/3 from the previous year.  Change can be rapid(keep in mind that the North pole ice pack floats and melting it does not raise sea levels).  Greenland ice, Iceland ice, and antarctic ice is not floating - it rests on dry land.  When it melts sea levels go up.  So thats what to be watching.  If we loose ice in those places - move higher.  Thats the point I'd like to make here - in the U.S. a rising sea will force relocation of 150 million people.  Think about it.  All the coastal cities, all the tidewater cities, and largely anything on the piedmont will be flooded.  Richmond, Virgina, where I grew up is about 250 feet above sea level and located on the fall line.  It'll become a coastal city.  I ask you, where will the resources come from to build housing for 150 million people?  Where will the energy come from?

Speaking of global warming - did you know that carbon dioxide levels in the atmosphere are higher now that in 700 million years?  Did you know that the changing wind patterns over the tropics of Capricorn and cancer are stirring the oceans and the oceans are not absorbing carbon dioxide as fast as they once did?  That last bit means atmospheric carbon dioxide is rising faster than in the past so warming is accelerating along with it.  How long will it take for carbon dioxide to "fall" out of the atmosphere?  How long did it take to lay down the plant matter in coal and oil and natural gas and seal them in the ground for a couple million years so we can dig them up and burn them?  It didn't happen overnight and thats the answer.  Its not going to happen quickly if at all.  Sure, plants take up carbon and bind it up in the plant structure.  When the plant dies it rots and gives up the carbon again as carbon dioxide.  Even if we all went out and planted trees like the mad men we are the reduction in carbon dioxide would be temporary.  In about 100 years the plants would die and begin to release the carbon back into the  atmosphere.  So - left to its own devices, the carbon dioxide we put in the air is, in human terms and in all of human experience, permanently there.

Maybe we can introduce a process that ties up carbon in some form like limestone so it can't easily get back into the air.  Fascinating idea.  Its Probably the single largest coordinated human activity since the building of the great pyramid at Giza.  Or - maybe the Three Rivers Dam.  So the scale is huge.  Not only do we need to capture existing airborne carbon dioxide but we also need to continue capturing it at the same rate that we are injecting it into the atmosphere.  Where are we going to get the resources necessary to capture and fix the carbon dioxide and where are we going to get the energy needed to do and continue doing it?

Basically we can deal with global warming if we have enough resources and enough energy.  But do we have enough energy?

We get energy from several sources but by far the largest source is from fossil fuels.  These include coal, natural gas, and petroleum.  Uranium, used in fission reactions, is not a fossil fuel so don't be getting wrapped around the axle there.  Our best estimates, go ahead, search the web for how much petroleum, natural gas, and coal are left in the ground, will have us running out of coal in 200 years (at the current rate of usage), oil in 40 years and natural gas in about 50 years.  Keep in mind that "running out" means reaching the point of exhausting the resource - there isn't any more.  But on the way to that point the resource will become increasingly rare.  The paradigm of supply and demand will be in play viscioiusly long before we reach the exhaustion point.  Now there are a lot of interesting technologies - like liquefaction and gasification of coal that can be usefull.  But the bottom line is pretty much the same.  You can switch your dependencies from one fossil fuel resource to another as each in turn becomes scarce and too expensive for you but you still exhaust them.  Then what?

While you are thinking about that think about this:  India and China have developing economies that are consuming resources faster and faster.   They will be our competition for the remaining resources.  So even if we use less, what we don't use will still be used.  As we find natural gas is too useful to generate electricity with because we have so many homes to heat, electric power will switch to coal.  We have 200 years of coal, right?  No. We have 200 years of coal if we don't increase the rate at which we dig it out of the ground.  If we switch to coal generation we will increase the rate of digging and shorten the amount of time left for the use of coal.

Similar thinking applies to oil.  Its very useful stuff.  The primary thing about oil is that it has a high energy density and its a liquid.  So its easy to refine and use.  A perfect fuel.  Unfortunately, we have very recently crossed a production peak in oil.  Since 2006, when production peaked world wide, the amount of oil produced each year began to decline.  It will continue to decline at an accelerating rate until it is exhausted.  Why has production peaked?  We are pretty good lookers when it comes to oil.  We have the technology and, since the oil crisis of the 70s, we have used that technology to find more oils.   We have been successful.  But we have also increased the use of oil to the point that consumption of oil exceeds the rate that we are finding it.  And, of course, oil fields do not produce oil at a constant rate.  As they age the rate of production tails off.  So older existing fields are producing less and less.  The rising price of oil makes it profitable to keep applying ever more expensive technologies to extract the last little bit of oil from old wells - but its not like you turned on a gusher.  The Russian oil fields that were in decline, were aided by the introduction of new technology that scavenged more oil from the old fields.  But the increase in production did not last and has begun to tail off again.

So - is there oil? Yes.  Is it unlimited in quantity?  No.    Is it going to be cheap?  No.  There is lots of oil tied up in Brazil and Colorado in shale and in Canada in tar sands.  It is now profitable for the Canadians to mine the oil from the tar sands.  Mind you, its not very efficient and takes a lot of heat and steam to get the oil out.  But it does produce more oil that it takes to extract the oil from the tar sand.  Is it cheap?  No.  But thats the way of the future.

Now, about global warming....  Where did you say the energy was going to come from to harvest the resources that we are going to use to rebuild the cities of the piedmont on the higher ground so we can relocate the 150 million folk flooded from their homes?  Who's got the money it will take to pay for that?  And what about binding up all that carbon dioxide into something more solid?  Where's the energy coming from to do that?

Ethenol - don't get me started.  Look at it this way, the amount of ethenol you can make is related to the amount of plant matter you can ferment.  The amount of plant matter you can ferment is related to the amount of plants you can grow.  The amount of plants you can grow is related to the amount of energy the plants can get from the sun and convert to plant matter.  The sun delivers about 100W per sq ft.  How much energy do you need? Whats the conversion rate of sunlight per sq ft to liter of ethenol produced?  How much land do you need to get that much ethenol?  Are you gonna want to eat something while you drive that SUV full of E85?

All right.  Hydrogen.  Good point.  Burning hydrogen sounds great to me.  Hydrogen and oxygen in - heat and water out.  Perfect.  We have thought about this for the last 30 years.  Transporting hydrogen is a little tricky because the molecule is so small. It seeps into metal pipelines and makes the steel brittle.  But that might be over come.  The other thing, unlike natural gas, hydrogen rises when released.  Natural gas is heavy and settles.  So a gas leak tends to hide its natural gas in the basement where when it lights it blows up the house.  Hydrogen hides in the attic so it probably will sneak out through mushroom vents and soffets.  Look at the Hindenberg.  Who burned to death in that accident?  No one.  The hydrogen rose and was  displaced by heavier air and burned up - not on the ground.  Neat!

So let me ask one little question or two.  Where does hydrogen come from?  Every time I see someone pushing hydrogen I see pictures of the sea.  What are they trying to say?  First, though, where does hydrogen come from?  Today it comes from natural gas.  They feed natural gas into a reaction chamber with steam and heat and produce hydrogen.  In this common form, its a fossil fuel right?  Did I mention that natural gas production will peak in 2020?  I didn't?  My bad.  Well there you go.  How do you feel about hydrogen now?  Should we be gassing up our SUVs with hydrogen to save the planet?  Well maybe.  Is there another source of hydrogen?  Remember the images of the sea?  Whats the sea water made of?  Yes - thats right.  Water is made of oxygen and hydrogen.  Thats why they show pictures of the sea and the "unlimited" supply of hydrogen. So - sweet.  We can take the hydrogen from sea water.

Wait!  How do you do that?  How do you get hydrogen from sea water?  There are several ways you can do it.  Electrolysis is one way.  Beaming microwaves through appropriately doped water will do it too.  But once again - where are you going to get the energy to rip the hydrogen away from the oxygen in the water?  Look at this (cause this is important).  There is no free lunch.  Just cause you want it to happened does not mean it will.  In this case generating electricity, which is key to getting the hydrogen from water,  obeys the rules of thermodynamics.  The process of making electricity is less that 50% efficient.  The part that does not become electricity is lost to the atmosphere as heat.  Yes, heat that abets global warming.  You know what else?  The process of separating hydrogen from the oxygen in water is also less than 50% efficient and it too gives off heat.  And you know what that means.  Well, that means that the process of making the electricity to make the hydrogen we want is only about 25% efficient end-to-end.  For every 4 BTU of heat we push into the making of hydrogen we only get 1 BTU worth of hydrogen out.  The rest goes to heat the atmosphere.  So its very inefficient.  Besides, hydrogen is not the only product of the activity generating the hydrogen.  The other bit is oxygen.  Lots of oxygen.  There will be great clouds of highly reactive oxygen blowing out of the generating stations for hydrogen.  Thats not going to be good.  Oxygen tends to make things burn.

So, for example, my back of the envelope calculation ( and please check me on this) is that if we were to replace the oil we use every day with hydrogen, we would need the entire output of the 90 odd electrical power generating nucular reactors supplying 25% of the U.S. power to do it.  Great!  All we have to do then is to build the power generating facilities to replace those reactors so we won't have to give up any electricity while we are converting over to use hydrogen.  This is going to be a big effort so there'll be plenty of jobs.  But we better start soon.  Historically we never licensed more than 9 reactors in a single year during the hey day of U.S. reactor construction and we have not build a power generating reactor since Seabrook 20 years ago.  It may take a decade or so for the first of a new breed of power reactors to come on line and by then, in 2018, natural gas will be nearing peak production.  If, on the other hand you want to continue using natural gas to heat your home, maybe we should start harder and faster (soon and more reactor construction).  Keep in mind, while you are planning your way to the future, that as fossil fuels run out that you may want to put in some electric base board heat - and that may take a few more reactors.

Now, before I move on, just focus, if you will, on heat.  All the oil we burn today becomes heat.  Heat to run our cars, heat to run our factories, heat to warm our toes.  But heat follows the laws of physics and in particular, entropy.  We are always increasing the entropy of the universe.  Along the way that heat contributes, ever so slightly, to global warming.  And what are we proposing to do?  We are proposing to use hydrogen to replace fossil fuels.  And how much more heat does it take to get the hydrogen?  Oh yeah!  We are going to release 4 times as much heat using hydrogen (counting its genration) to do the same work that we get from fossil fuels today.  Interesting approach.

Ok.  It looks like we have solved the hydrogen problem but for one or two details.  First, uranium.  Where are you going to get enough uranium with the rest of the world trying to follow your strategy?  Uranium too, is a limited resource.  Maybe breeder reactors will help.  We'll convert U235 to Plutonium and build reactors that run on Plutonium (the most lethal substance on the planet).  The other little question you have heard before. Its just "where are we going to find the energy and resources to build the reactors to produce the electricity to make the hydrogen"?  Seems to me that at a time when oil is becoming pricey we are at the same time saying we are going to use a lot of it to build the solution to the problem we got into by using it. Maybe we can do it.  Its not going to be cheap.  By the way - be sure to budget energy and funds to build the infrastructure to pipe all that hydrogen around the country and all the home furnaces that  will have to be re-tooled to use it.

Fusion - I like it.  Seems like the answer, finally.  But its not here yet and, I think its a generation away (or two).  All we have to do is preserve humanity long enough to get there.  Fusion and hydrogen.  Forget Giza!  These are the largest technical challenges to be undertaken by mankind.  Undertaken at a time of global warming, increasing population, shortages of everything except people.  If we had fusion today, I think we might be able to build our way into the future.  But we don't.  By the time we get fusion, if we get fusion, the resources we need to build the solution will have been consumed.   I can see it now. You and your dibble stick building fusion reactors.

But I don't think its as bleak as it looks.  Our ancestors came to this land with sails.  Wind power - air heated by the sun.  They lived.  They prospered. We can do that too.  We know so much more than they did.  We may have to live differently - conservatively.  We have to use our resources well, solar heating( actively and passively), solar voltaic, wind generators, husbanding our use of fossil fuels for use in the most important things and not waste energy.  We won't be able to fix global warming for the foreseeable future.  Some other generation will have to solve that problem.

And, I think, we won't be able to move forward with 6 billion people.  We are pretty close to or past the size of a population that we can maintain.  We depend on fossil fuels to sustain the population we have.  We have done nothing yet to mitigate our use of energy -not just fossil fuels.  Consider the following scenario.

Its 2007 and we have enough oil for our needs.  We make what from oil?  Plastics, medicines, tires, heat for manufacturing, fertilizer for farms and yards, we make diesel to run trucks and farm equipment and heating oil to heat our homes.  Next year, oil production will go down 3% just as it did this year.  Prices will go up for oil based products but here will be no shortage.  But in a couple years, the oil production will be down 10% from the peak and there won't be enough to go around.  The free market will help that a bit and people will use buses and carpools.  But every year the problem will get worse. In a decade oil production will be down 45%.  Somewhere in there you have to decide what are the important uses of oil and what are frivolous?  I think keeping farms running to feed us is important.  Heating oil is important.  SUV and jet fuel - not so important.  And what about construction and all those trucks it takes to move goods about?  Over the years the use of oil will have to be prioritized.  Thats going to change the way we live.  Once oil shortage begins to eat into the amount of land under cultivation, a grim future will emerge.  Those who can do victory gardens and the like, may survive.  But the green revolution, which revolutionized agriculture and depends so heavily on oil, will not survive.  And it will take many of us with it in its passing.

Its a brave new world.  We need to decide what to do as species pretty soon.  It may even be too late. But we don't know that so we need to start doing smart things.  Long term things. Today, not tomorrow, stop wasting energy.  Buy the species a little time.