He wants to save the world

To say that most economists lack color and charisma is to state the obvious.

To be sure, there have been a few exceptions to this generalization. Today we have Jeffrey Sachs --economist/preacher/rock star -- whose Energizer bunny-ness inspires young people even as it frustrates and irritates his peers.

The interesting thing about Sachs, however, is that once (if?) you get past the self-promotion and the vague resemblance to Elmer Gantry, he's actually an accomplished economist whose boundless energy is deployed in behalf of laudable social goals. He writes clearly and well, too, as his new book "Common Wealth: Economics for a Crowded Planet" makes clear. Never one to think small or to privilege modesty, Sachs takes on as his task in "Common Wealth" the development of a road map to save mankind. In 339 pages of text, he, in fact, develops such a road map, a not half-bad one.

Sachs' road map is predicated on his assessment of the bind humans have gotten themselves into over the past 2 centuries, an era he refers to as the Anthropocene -- or human-dominated earth, a term coined by Nobel laureate chemist Paul Crutzen.

Ironically, this bind grows directly out of one of the great achievements humans have registered since 1750 or so: sustained economic growth over more and more parts of the world. Simply put, the massive productivity gains humans have engineered into economic life via industrialization and the systematic employment of scientific knowledge in the material realm have resulted in levels of prosperity and living standards that have put increasing pressure on the earth's resources.

Such pressure has been exacerbated by the huge increase in human population occasioned by economic growth and development. Higher and higher living standards for more and more people lead to greater and greater environmental stress, in other words. And, according to Sachs, we've just about reached the point of no return. Here's where Sachs' road map -- a sustainable development plan "for a crowded planet" -- comes in.

According to the author, who directs the Earth Institute at Columbia University, sustainable development means that over the next few decades "we" will at a minimum have to meet four or five key challenges, to wit: protect the environment, and, in so doing, slow down, if not reverse global warming; stabilize world population; narrow the gap between rich and poor; and eliminate extreme poverty. To meet these challenges, Sachs argues, we will have to develop both new international institutions and more cooperative means of apprehending -- and operating in -- the world. Although these challenges, taken together, are daunting, Sachs is relatively optimistic about "our" ability to meet them without drastic modifications in lives or lifestyles, assuming enlightened leadership and sufficient resolve. In his view, that is to say, the technology is there or will soon be there to meet these challenges, and, if we act decisively and expeditiously, solutions to the problems entailed will not cost all that much -- no more than a few percent of world output. But we must first commit to global cooperation and a sustainable-development agenda, and we must do so now.

Sachs' moral fervor, bordering at times on preachiness, grows out of the time sensitivity we face in addressing the problems outlined in "Common Wealth." It would be a pity if this authorial tic leads readers to put down the book because "Common Wealth" is replete with good scientific and economic data, and Sachs' arguments are at once nuanced and balanced.