I read previously seen estimates in excess of 1 trillion barrels of reserve. The scientific american article states that there is about 649 billion barrels of known "cheap pumpable" oil reserves. However consumption is extremely high, check out this site:

Canadian & International Oil Forecasts

Look for the table under the heading Forcasts ---> Midterm Projections ---> Consumption ---> Petroleum(Oil) ---> World Total, 2005-2020 (million barrels per day)

You will find that worldwide consumption is around 50 million barrels per day, or 18.25 billion barrels per year. So the known oil reserves of 649 billion barrels should last 36 years, right? But notice that consumption is increasing. If you plot this increasing trend with a straight line graph you will find that the oil will run out much sooner, perhaps as early as 2025. But like I said the dynamic is much more: Canada will run out in 2 years, and most countries will also run out in the next 15 years. By 2010 more than 50% of world oil will come from OPEC countries, and by 2015 Saudi Arabia will be the world's largest source of crude.

If we go with the solar concentrator scheme to produce methanol as a substitute we will need at least 1356 square miles of parabolic troughs. To put this area in perspective here is land area for the city of Toronto:

Statistics
Area: 3,646 square miles [9,443.1 square kilometers]
Population: 4,263,757
Time Zone: Eastern Standard Time, five hours behind Greenwich Mean Time
Province: Ontario

There is plenty of room for this sort of infrastructure in my opinion.