Life places huge demands on most of us at some time; our character and resolve is put to the test.

And coming is the granddaddy of circumstances mankind has ever faced: the likelihood of global disaster caused by global warming. Only one small group might be capable of leading the effort to avert this catastrophe: the chief executives of Standard & Poor’s 500 companies.

No other group appears capable of stepping up to the task. Global warming, often confused with weather, and energy production are subjects that are complex and difficult for nonscientists to understand. And importantly, greed and self-interest of key players — the fossil fuel companies, pandering politicians — now overrides their objectivity and clear thinking.

Most S&P 500 CEOs have been selected for their position because they have demonstrated a rare combination of the intelligence, vision and leadership required for confronting difficult issues. And because global warming will have a major business impact, it is certainly a CEO’s corporate responsibility to deal with this issue.

The popular press headline story is that we have to keep the mean global land surface temperature from increasing more than 2 degrees Celsius, and that it might be possible to accomplish this by voluntary measures — principally conservation and wind and solar power. Regrettably, this is a delusional story.

Just a few key points:

• A 2 degree Celsius increase will take us above anything seen in the Holocene, the interglacial period that fostered the emergence of modern man. Many leading scientists believe an increase of 2 degrees will prove to be catastrophic.

• Once a 2 degree Celsius increase occurs, a further, more rapid “nonlinear” increase in global warming could be initiated — with methane release, with evermore rapid ice melt, ocean current change — all poorly understood but also recognized as significant risk factors.

• Pencil to paper engineering and math shows that the environmentalist’s solution of combining conservation, wind and solar power is not a practical answer. In fact, it is more likely a false ideology that keeps us from focusing on a substantive answer. Two realities are key here: One, we live in a world that will go from today’s 7 billion people to more than 9 billion by 2050, most wanting to live like the developed Western world. And second, we have entered into a global economic system that is seemingly growth dependent and where huge quantities of energy are essential for this growth and lifestyle.

Is there a way out of this conundrum? The answer is to very quickly develop massive amounts of carbon-free energy, leaving most of the remaining fossil fuel in the ground. And there is but one way to do that: to launch, very quickly, a “Manhattan” or “going to the moon” program, with the cornerstone of that effort being the development of nuclear reactors for generating essentially unlimited amounts of carbon-free energy.

Fortunately, we have the technology to do this. And in answer to everyone’s immediate concern, the technology already exists for building reactors that are extremely safe and resistant to weapon proliferation. Like all aspects of technology, nuclear reactor-sourced energy rests on a continuum of development.

The U.S. has about 100 current operating light water (LW) reactors, producing about 20 percent of our electricity, and about 8 percent of total energy consumption. Worldwide there are about 437. These designs, while generally safe, are obsolete and inefficient.

Improved, but still largely of conventional design, are the LW reactors now being built. The Westinghouse AP-1000 is an example, with several under construction in China. A next-generation design, ready to be built by GE-Hitachi, represents a more advanced and efficient design. It is based on advanced reactor work done during the U.S. nuclear development programs decades ago.

Far more advanced are a large number of small modular reactors (SMR) poised for final development and which could be commercialized in years, not decades, given a committed “going to the moon” program. These smaller designs can be built in a factory, need no external cooling system, cannot melt down, run at atmospheric pressure, can be designed to use the nuclear waste the world has accumulated, and are impractical for making nuclear weapon materials.

The problem, and a huge one, however, is that capitalizing on nuclear-based carbon-free energy requires out-of-the-box thinking. Unfounded fear of anything nuclear, entrenched thinking, denial, and ideological myths are stopping us from saving ourselves. And the S&P companies will not be immune from the chaos and destruction that global warming brings.

The issue is whether or not this group — the CEOs — has the will to step up, in a substantive way, to the existential issue we face. There is hope. For example, General Mills, Procter & Gamble, Unilever, Cargill and other companies have said they are now committed to reducing the risks of global warming. This resembles, in an uncanny way, the lead that some of the company CEOs took in saying that gay people have the right to be treated as equal humans, helping usher in, relatively quickly, a major societal change.

Never before has there been a call to arms comparable to this one. And it appears that there is only one group capable of the leadership needed to move the world to the only answer — unlimited, safe, carbon free, nuclear-based energy. That group is the S&P 500 CEOs. They can do it responsibly. And they need everyone’s support and encouragement.