Hold onto that root beer can: The world needs it. The Earth's 51/2 billion people aren't replenishing their resources; we must move from a throw-away society to a recycling one.
That's the conclusion reached by a Washington-based global-issues think tank, the Worldwatch Institute, in a just-published analysis by senior researcher William U. Chandler. Some findings:
* Throwing away an aluminum beverage can wastes as much energy as pouring out such a can half-filled with gasoline.
* World waste-paper consumption has increased 140 percent since 1965, with Japan recovering 45 percent and the United States only 26 percent. But the US leads the world in exporting bulk waste paper.
* Nine American states have now enacted beverage-container deposit laws: Americans now recycle 54 percent of the cans they use and the trend is growing; the latest states are Massachusetts, Delaware, and New York.
* Junked automobiles are an asset: Those recycled in the US account for 4 percent of the world's annual steel production.
* The US recovers 35 percent of its scrap steel, but the Soviet Union only 17 percent - perhaps due to its ''complicated and highly centralized control of materials.''
* There is a dynamic world trade in scrap paper and aluminum. Iron and steel is big and getting bigger; but instead of encouraging this, some countries are holding it back with protectionist laws.
* The still-wasteful US last year threw away more recyclable aluminum in discarded beverage cans than the continent of Africa produced.
Recycling, it turns out, dates all the way back to Prometheus: His younger brother Epimetheus, according to the Greek myth, had the job of allocating all the earth's resources to various species. But he was so recklessly extravagant at first in handing them out that he ran out of supplies before he came to man, precipitating the first energy crisis.
Prometheus stepped in by stealing fire from the sun. Where's Prometheus now? William U. Chandler, in the new study for Worldwatch Institute, puts it more practically: He says a lot of people don't recognize recycling's necessity.
''Many nations continue to mask the growing necessity of capturing recycling's benefits,'' he writes. ''They subsidize energy use with price controls, production tax incentives, and the uncontrolled environmental cost of producing and using energy in materials processing.''
The author says, ''The scarcity economy is here to stay. The full cost of energy-intensive materials is not accurately represented in their prices, and the incentive to reduce these costs is diminished. . . . Export barriers have been erected specifically to reduce the price of metal scrap, a measure that reduces the incentive to collect scrap and makes it less available as a substitute for primary materials. Countries performing best in recycling have avoided these pitfalls.''
Mr. Chandler is shocked at the sight of all those daily newspapers piling up for the trash collector, and says they ought to be recycled. But he is not blaming Epimetheus. Chandler insists that materials recycling is coming, like it or not.
Look at what happened in Sweden: It suffered from 400,000 abandoned car junks littering the countryside. Now a 1976 law requires disposal to scrap dealers. And a Norway law requires a $100 deposit on new cars with a refundable $50 when the battered old thing is turned in at the end of its ride.
Recycling is beginning and is world-wide. For example, says the study, deposits are now required on all beverage containers sold in Sweden, Denmark, Norway, the Netherlands, and several provinces in Canada.