It has become commonplace to assert that the days of newsprint are numbered – perhaps the days of newspapers themselves. Yale University’s library recently closed its newspaper reading room. Asked last week about the suggestion that The New York Times might print is last edition in 2015, publisher Arthur O. Sulzberger Jr. told an industry association in London, “We will stop printing the New York Times some time in the future, date TBD [to be determined].”  (Sulzberger’s office subsequently explained that he had been “joking.”)

The future of newsprint, though, is no joking matter. Consider, for instance, the likely impact of global warming on the news business.

A hotter climate means bigger cities and more trees. The UN predicts that 60 percent of the world’s population will live in cities by 2030, up from 47 percent in 2000 and 30 percent in 1950. Bigger cities mean more mass transit and shorter lines of distribution of paper editions to those who willing to pay. Better rates of community penetration would make for higher advertising rates.

More trees will mean, among other things, cheaper paper. As The Economist pointed out last week, forests have a new economic basis, for they are often the cheapest way to tackle the problem of removing carbon from the atmosphere.

But, you say,  nobody wants paper editions, at whatever price? Think again.

Cities are on my mind because I have been reading Climatopolis: How Our Cities Will Thrive in the Hotter Future, by Matthew Kahn. It is a short, accessible, engaging book of a sort that can be either good or bad, depending on the knowledgeability of the author. Climatopolis, as it happens, is very good. Kahn, an economist at the University of California at Los Angeles and a protégé of Gary Becker (of the University of Chicago), has extensive experience in carbon policy and a solid grounding in climate science.

There’s not the slightest doubt in Kahn’s mind that global warming is underway and that it is essentially irreversible. On the expected response to it, he distinguishes between the views of behavioral and neoclassical economists.  Behavioral economists, he says, “have a fundamentally pessimistic view of humans as lazy and myopic and unwilling to sacrifice for their long-term good.” In contrast, he says, “neoclassical economists view people as forward-looking and willing to make choices today in response to anticipated threats.”

I’m not certain that the distinction is nearly as simple as that.  And I doubt that Kahn is entirely correct when he writes, “We’re not all on board one big ship that we can save through one big collective decision. Instead we’ll be ‘saved’ by a multitude of self-interested people armed only with their wits and access to capitalist markets.”  I have a hunch that social choice and collective action are going to turn out to be pretty important, too. (He doesn’t mention, for example, the 1987 Montreal Protocol aimed at limiting substances that deplete the ozone layer.)   But I am with Kahn completely when he notes the evidence of global warming is compelling.

Ecologists have devoted their careers to examining the geographical distributions of where different creatures live and documenting the ‘coincidental patterns’ showing that many creatures have been on the move, seeking out more hospitable climate conditions in a hotter world. I have taken it for granted that humans are next.

Newspapers are on my mind, too, and not just because I expect them to referee the ongoing debate. I have read a couple of good books about them, too, recently, War at The Wall Street Journal: Inside the Struggle to Control an American Business Empire, by Sarah Ellison; and Morning Miracle: Inside The Washington Post, A Great Newspaper Fights For Its Life, by Dave Kindred.  Each writer is a veteran staff reporter of the paper in question, and each has delivered a wonderful specimen of the reporter’s art.

But each project is essentially backward-looking.  Neither reporter has much in the way of sources on the continuing debate about newpapers’ future. When a writer for the Columbia Journalism Review turned up at The Washington Post recently, eager to rehash the old days, editor Marcus Brauchli correctly reminded him – twice, for emphasis — that the golden age of newspapers was “an era that has been amply described.”

The fate of the cities is relevant to the producers of news because cities are the units around which newspapers and their coverage are organized and will continue to be. Even national newspapers are city-based (in Manhattan in the case of the Times and the WSJ, in Washington, DC, in the case of USA Today (though its offices are in suburban McLean, Virginia). The Washington Post has national importance, but it is essentially a metropolitan newspaper – by far the healthiest of a class that includes the Los Angeles Times, the Chicago Tribune, the Philadelphia Inquirer, the Baltimore Sun and The Boston Globe. Newsdealers have long distinguished between fancy papers, able to charge a premium (usually double), and the local ones.  The distinction persists.

What reason is there to think that significant numbers of city-dwellers will continue to prefer the paper product to web pages, computer directories or iPad display? Sheer utility is one reason. Broadsheets are easier to read, at least in some times and places: the breafast table, the office desk. (On a recent shuttle flight to Washington, almost nobody was reading papers in the morning; perhaps a third of the passengers were reading newpapers or doing puzzles on the way home.) Nobody knows how today’s kids will adapt, after today’s enthusiasm for being in the van of history has passed. But the relevant question is, in any event, not how they get their news in college, but what they read after they get their first good job.

Bulk is another consideration.  There’s nothing that says newspapers have to be at their golden-age strength to deliver the goods. In Kindred’s book, Bob Woodward notes that in the glory days of its Watergate coverage, the Post’s newsroom staff was 350 persons, not the 900 of a few years ago.

True, Facebook has interposed yet another layer of interactive media between the reader and his daily life.  Social media, like intentional search, will attract advertising, a large fraction of which used to flow by default to print. For precisely that reason, though, daily newspapers will offer a respite to those who find it useful: a thoughtful and well-ordered budget of new information, finite in its demands on the reader, comprehensive in some degree, portable, shareable, and durable in a way that pixels aren’t.

In fact, the single dimension in which publishers have the greatest freedom to maneuver in the face of the computer onslaught is in the size of the package they deliver to readers, and therefore its price:  62 pages (like the Saturday WSJ?) or 50 pages (like the weekend Financial Times?). Or 42 pages (like the Saturday NYTimes?)  Or only half as many of each?  Four sections?  Or two? $2 a copy weekdays?  Or $1? With what price for cross-subscriptions to wider, deeper digital content? It’s worth remembering that newspapers have cut their prices in the past, sometimes with great success.

The point is that apparently extraneous forces like global warming make it necessary to think strategically well into the future. Such considerations may seem to come from left field, but that is the unpredictable nature of business life.

For above all, the printing press is a barrier to entry.  Its print edition is what distinguishes newspapers (and their websites) from everything else under the sun.  A news purveyor (of which there are now millions) is just a website, whatever its advertising income. The ability to bring together advertisers and a certain kind of elite audience – its composition yet to be determined – is what will make print newspapers a durable medium – similar, but senior to, the various public broadcasting companies in the industrial world.

Thus a much better answer to the question about the future of print is the one that New York Times executive editor Bill Keller gave host Tom Ashbrook last week on the NPR radio show On Point. He would place money, Keller said, that the Times will be in print: “ten years from now, twenty years from now,” even if, eventually, newsprint editions might become a “boutique” product, like vinyl recordings. “I expect that in my lifetime there will be a New York Times in print.”