Austin's zero-waste program got me thinking about this one. I'm not sure the answer is as obvious as people think it is.
Recycling newspapers clearly uses less energy than making newsprint from virgin pulp. A lot less energy -- perhaps 40% less. If all we had to worry about was the energy involved, the equation would be simple to solve.
But we also have to account for the carbon absorbed by trees.
Most people think saving trees is the main advantage of recycling newspapers. But people are worried about the wrong trees. The trees that matter aren't the ones that are cut down, they're the ones that aren't planted.
A lot of the trees that are cut down for pulp are specifically grown to be cut down. Tree farm owners expect a return on their investment in the land; they aren't in the business of providing free carbon absorption. If they don't get a good enough return on the timber, some of them will switch to a different use.
Take Landowner Larry. Larry's just clear-cut 500 acres for pulpwood, and he's trying to decide what to do with his land. Larry ordinarily would replant his 500 acres with saplings then sit back and wait 40 years for another big payday (or sell to someone willing to wait for the payday). But Larry's noticed the BIG PUSH to recycle newsprint; the experts predict demand will be cut by, say, 40% in 40 years. Larry's worried about that. Forty years is a long time to wait for a big payday when the payday might not be so big.
Larry's land just happens to be good for farming, too. Corn especially. Larry can read the newspaper, and knows the government is pushing a loony policy to encourage American farmers to plow under as much land as possible for biofuels. Billions of gallons of ethanol per year, or something like that. Larry decides he's better off renting his land to farmers. They can make a bunch of money growing ethanol, which means he can get a better return than he expects from growing timber. (We can also imagine Larry instead selling to a developer, who will grow houses and roads and strip malls.)
Our carbon emissions have taken a double whammy. We've lost 500 acres of carbon-sucking saplings and we've replaced them with 500 acres of carbon-spewing farmland (or suburbs). Sure, our push to recycle newspaper has saved some trees in the short term, but with the likely consequence that timberland will be converted to farmland or housing. (I know that some timberland can't be put to alternative uses -- for example, land deep in the middle of a national forest -- but we're hypothesizing a timberland owner who is on the bubble.)
I'm not sure how to calculate recycling's net carbon benefit once lost timberland is taken into account. For starters, it's hard to tell how much timberland will really be taken out of production; a 10% decrease in the price of timber (caused by slackening demand) does not necessarily mean a 10% decrease in the amount of timberland under cultivation. In other words, I don't know the price elasticity of the supply of timberland. I do know, though, that the price elasticity will rise as the value of farmland rises. Simply put, our government is doing all it can to incentivize timberland owners to convert their land to farmland. Some landowners will respond to the incentives, and will do so even more quickly if they expect the long-term demand for their trees to slacken.
Since I don't know how much timberland we will lose by depressing the demand for trees, I don't know whether we will emit more or less carbon by recycling most of our newsprint. It is possible that recycling saves so much energy we can ignore trees. But that's not obviously true -- one acre of trees can absorb as much as four tons of carbon per year, which is a lot of carbon. And that's before we've taken into account the extra carbon generated by the alternative use of the land.
Note also that as energy becomes greener, recycled newsprint's carbon advantage over virgin newsprint will shrink. Considering the (likely) declining benefit and the growing appeal of alternative uses for timberland such as farmland, our optimal long-term carbon strategy may be to induce an increase in the demand for timber.
This isn't to knock Austin's zero-waste program. Newspapers take up a lot more landfill space than plastic bags. As long as the city's cost of recycling newsprint is less than the cost of buying landfill space for newsprint, then the city ought to move toward a zero-waste program. The carbon calculation looks intractable, though. Too intractable for the city to be confident that recycling newprint will do anything for global warming in the long run.
