Scientists in Melbourne, Australia, have decided estimates of sea level increases are woefully inadequate. Instead of going up 2-4 feet by 2100, the increase will be more on the order of 6-7 feet.

A couple of feet may not seem like much of a jump, unless you happen to be one of the hundreds of millions of people who would, literally, be up to their eyelids in sea water.

On the other hand, teams of scientists in Europe and Asia, with a little help from the World Health Organization, reckon 2.3 billion people live in water-stressed areas of the planet, and another billion or so don’t have access to clean water.

Water, water everywhere and not a drop to drink.

The trick, as it turns out, is turning an enemy into a friend. In this case that means turning sea water into drinking water, about which Greek philosopher Aristotle once said: “Salt water, when it turns into vapor, becomes sweet, and the vapor does not form salt water again when it condenses.”

Aristotle made that observation on or about 350 BC, which predates our interest in desalting sea water by more than a few centuries.

A good way to think about desalination is that Earth’s oceans contain more than 97 percent of the planet’s water resources, but at the most recent count, desalination provides only about 1 percent of the world’s drinking water. Clearly, there is much room for improvement.

What seems to be missing is the will to take the steps necessary to create more desal facilities, and more research on how to reduce the costs of removing salt from sea water.

Years ago, during one of California’s many extreme drought episodes, voters in Santa Barbara approved construction of a desalination plant. As fate would have it, rains came not long after that vote, and the equipment sat idle for years.

Those voters approved the plant and its tens of million of dollars in costs, fully aware that an acre-foot of desalinated sea water would cost exponentially more than an acre-foot from the Cachuma reservoir.

We’d never want to accuse Santa Barbara voters of being overly smart, but they at least understood back in the early 1990s that paying a small fortune for water was a far better option than having no water, at any cost.

Those costs remain very high, compared with what we are accustomed to paying for potable water, and there aren’t really any less-cost options on the horizon. As one scientist said: “There aren’t any magic bullets” with regard to desal’s costs. But, looking at this problem in a logical way, really, what choice do we have?

Countries that are chronically dry adopted desalination processes decades ago. As recently as 2004, Israel got all its potable water from wells or collected from sparse rainfall. As of the first of this year, two-thirds of that nation’s water is supplied by five desal plants.

Humanity seems to be divided between billions of people without water, and billions more at risk of being inundated. If the science community is correct about sea-level rise, many of us will have to make hard choices in the years ahead.

Given the scientific evidence, it seems we could be putting available resources to better use, and while locally we don’t need extra water right now, California’s history indicates those drought episodes will just keep coming at us.

The water is there, essentially at our doorstep. We just have to find the will and the way to best use it.