Though my profession ensures the precise and effective execution of nuclear weapons if necessary, reading Nevil Shute’s On the Beach made me wonder, “Why do we still have so many nukes? Can deterrence be achieved with a lower number, one that doesn’t eradicate human life?”

There are plenty of organizations in this world dedicated to the abolition of nuclear weapons. When considering the massive potential for destruction and death that nuclear weapons pose on the world, this objective would seem a laudable one. Indeed, even President Obama in the 2010 Nuclear Posture Review stressed the eventual need for a “world without nuclear weapons.”

Yet, one cannot ignore that armed conflicts between the major powers have been avoided – likely because of nukes, directly and indirectly. This is why nuclear weapons are considered the bedrock of our national security.

According to the Nuclear Threat Initiative, the world shares nearly 16,000 nuclear weapons between nine countries. The estimated combined nuclear yield of such an arsenal is 5 gigatons. Nobody can logically dispute that the world has too many nuclear weapons.

The only acceptable global arsenal is one that might still allow human life. Unfortunately, only a few studies have even attempted to determine what an acceptable level of nuclear weapons might be. One study estimates that 100 – 1000 megatons of combined nuclear yield would bring the radioactive content of our atmosphere to highly dangerous, life-eliminating levels, similar to the scene painted in Nevil Shute’s book. That is 2%-20% the level we currently possess. Yet other research suggeststhat the resultant dust cloud of less than 1 megaton (0.05% of our current global yield), split between 50 lower-yield nuclear weapons could send us into a mini-ice age, killing nearly 1 billion people.

Though helpful, neither of these scenarios gives us an accurate picture of a life-allowing level of nuclear arms. Therefore, governments worldwide should make it a priority to determine what that level might be. At least then we could be assured that our children have a chance at life if deterrence were to fail.

Some might also question whether it is even possible to maintain such a nuclear arsenal, one that is a mere fraction of what the world currently possesses, while still maintaining the peace that nuclear weapons offer. In other words, if the governments of the world determined that 100 megatons, split between 250 nukes detonated in a global conflict would be the maximum numbers that could still allow human life, would that arsenal still dissuade major conventional and nuclear conflicts?

Needless to say, any major nuclear engagement has the potential to destroy all of us. That weighs heavily on my mind – and it should weigh heavily on the mind of any living, breathing human. Steps toward a more substantial nuclear drawdown must be taken. We need to be doing more. Yet, national and world security must be considered. Nuclear weapons have afforded the relative peace we have relished for 70 years. That also cannot be ignored.

Is the balance between world security and the guarantee of continued life on this planet a possible scenario? Even if it’s not, perhaps the lesser of both evils is the right choice in this conundrum. Maybe then, at least we ensure that our world would continue to be a place that you and I, and our posterity, are allowed to exist.