By Reese Palley

There's little time left to reduce the globe-warming gases in our atmosphere. The first step toward doing so must be replacing more than 1,500 coal-fired electricity plants in the United States, which dump millions of tons of carbon dioxide and other greenhouse gasses into the atmosphere each year.

Population projections indicate that in the next few decades, we will need half again as much electrical energy as these plants produce now. Should we continue to depend on coal and other fossil fuels, global warming will accelerate beyond our ability to cope with it.

The only form of energy that exists on the scale required to replace these coal-fired monsters is nuclear. In recognition of this, the Obama administration is ramping up the construction of high-capacity light-water reactors, the most common type of nuclear plant.

However, the ramping up is a pittance compared to the need. Present plans call for seven of these plants in the next 10 years, but the energy industry estimates the minimum need is for 100 plants over the next 20 years.

With the present approach, it's clear that we cannot make a dent in carbon dioxide emissions. The problems are of scale and risk.

These nuclear plants require upward of $15 billion to complete and between 10 and 15 years to come on line, after which it can take another decade for them to break even. Measuring the financial risk of spending that much money over that many years is difficult, if not impossible.

For example, what if, while a new reactor is being developed, there is a minor nuclear accident similar to Three Mile Island somewhere in the world? Three Mile Island killed no one and was fully contained, and yet it halted nuclear construction for 20 years and yielded endless restrictive and expensive regulatory measures.

Or what if, as we can reasonably expect in a quarter of a century, nuclear innovations change the financial expectations for light-water reactors? Or what if, mid-construction, there is another credit panic such as the one we just experienced?

PSEG's recently proposed addition of a fourth nuclear reactor at its complex in Salem County, N.J., faces a wait of at least three years to get approval, and then perhaps five or six more years for construction. And the plant would not begin to pay off for a dozen years, after which it would live on until the year 2100 as a technological troglodyte that was designed several decades earlier.

Because of the huge scale and spans of time involved in developing such plants, the financial risks become practically unquantifiable. Under these circumstances, raising private capital becomes prohibitively expensive. The only alternative is government financing and a nationalized nuclear-energy industry.

We know that will not happen in this country. We are saddled with a capitalist economy that cannot finance a nuclear industry and a capitalist democracy that will not allow nationalization.

Since the overall problem is of scale combined with risk, one logical course would be to reduce the scale of nuclear plants. This would allow the energy industry to adjust to unforeseen events on an incremental basis. That in turn would allow the private sector to pursue its traditional function of supplying the capital.

The solution lies in methods of nuclear generation that are already verging on financial and technological feasibility. Small nuclear reactors, most of which are inherently safe, provide energy at a fraction of the cost of light-water reactors, can come on line in a relatively short time, and are deliverable by tractor-trailer.

Most important, since time is short and we need to replace so much fossil-fuel energy, small nuclear reactors could be factory-built on multiple assembly lines.

Small nuclear reactors await the approval of our regulatory agencies, and they must be considered as a first line of attack on the global-warming problem. They are here now and, with a crash program approximating the Apollo lunar landing effort, they just might take our fossil-fuel plants off line as quickly as we got to the moon. What are we waiting for?