Consider this. The U.S. real estate market approaches an unprecedented challenge: hundreds of thousands of coastal properties will soon face persistent or recurrent flooding.

Flooding devalues property. In addition to threatening the tax base of many communities, ripple effects will stress real estate developers and investors, insurers, banks and mortgage lenders.

Previous housing market crashes have been self-limited, with mainly transient effects on public economies. This one is different. The cause of the flooding — inexorably rising sea levels now underway — will not remit, only worsen.

Within three decades, more than 300,000 existing U.S. homes and commercial properties will confront chronic disruptive flooding, defined as “high-tide flooding occurring at least 26 times a year.” (Storm-surge flooding from hurricanes doesn’t count.) They are currently valued at $135 billion.

In 80 years, encroaching waters will threaten additional holdings worth more than $1 trillion, including 2.4 million homes and 107,000 commercial properties.

In the near term, 150,000 existing homes and 7,000 commercial enterprises could be damaged within 15 years, a $65 billion ding, depending on which areas are hit hardest, and how widespread the flooding is at a given point in time.

It is physically and fiscally impossible to save them all. “Flood-proofing” projects such as sea walls are not universally effective even in the short term, and cost a lot. In some places the potential sea-level liabilities are so devastating that communities are considering whether moving out is the least worse option.

Loss of tax bases will compromise school funding, road maintenance, emergency services, and other elements of infrastructure. Services could be cut even as roads wash out.

In around 120 coastal communities, 20 percent of local taxes come from properties at greatest risk for flooding in the next 30 years. A fourth of those municipalities could lose over half of their tax base.

Far from the coasts, markets that work with coastal mortgages and large-scale development will get pounded. Municipal credit ratings will downgrade. Some coastal refineries would eventually be forced to relocate, causing widespread and persistent fuel shortages (not necessarily a bad thing, if we plan for it). Cumulative consequences would skew the whole economy.

Logistical challenges accompany the financial ones. Displaced families and businesses will have to be relocated, sometimes permanently. Higher rates of traumatic injury and infectious disease will emerge, even as medical systems and infrastructure are degraded, and disaster plans rendered obsolete.

Meanwhile, outdated policies and incentives actually continue to encourage coastal development. President Trump has repealed the federal flood risk management standard. Buyers and investors need not be informed of the probable consequences of sea rise when they consider specific coastal properties. Every day we’re creating more to lose.

At this point, I’ll guess that most of our readers have not previously viewed these particular numbers and assertions, though they are easily available from reliable sources. Some thoughtful people believe that the public should not be asked to confront such disturbing information, and that one should not write about it in such straightforward terms.

Unfortunately, they might be right.

A compelling perspective, backed by focus groups and some psychological research, maintains that if scientists offer complete and accurate projections of climate change, people will freak out, give up hope, stop trying. Mind and emotions recoil from information that is at once horrifying and inconceivable. Tone down the message, or it just won’t work.

How about an amusing limerick instead?

It might be true — if we escalate the urgency of informing the public, they will just reject our message, and they will not act. It is almost certainly true that if the public does not endorse drastic measures and national “war-footing” sacrifices rapidly, the outcome will be the same as ignoring the problem entirely - mass disruption of cultures and societies for centuries to come.

“It is no longer possible to follow a gradual transition path to restore a safe climate,” states a new report, “What Lies Beneath: The Understatement of Existential Climate Risk.”

Normally the scientific community is overly cautious in releasing scary data, a matter of decorum as well as a pragmatic precaution against charges of “hysteria.” “The bulk of climate research has tended to underplay (the) risks, and exhibited a preference for conservative projections and scholarly reticence.” As a result, many climate impact forecasts have actually underestimated the extent and rate of change.

The report says that a “fast, emergency-scale transition to a post-fossil fuel world is absolutely necessary to address climate change.” The solution continues to be excluded from policy debate because powerful interests view it as “too disruptive.”

This lack of imagination and political will could disfigure humanity’s future, permanently and drastically degrading our present living standards, and in some cases causing widespread human die-offs. Even the globe’s premier climate research agency, the IPCC, has erred on the side of “least drama,” minimizing the more extreme and damaging probabilities. Understatement gets more dangerous as climate impacts accelerate.

Yes, transition would be difficult and complex. The business models of some vested interests would disintegrate. As individuals, we would all be stressed to endure a daunting new daily life. Yet that’s the lesser evil.

Cassandra, daughter of Priam, king of Troy, offended Apollo. He blessed her with the gift of prophecy; his curse was that nobody would believe her. She predicted the total destruction of Troy, and so was thought to be hysterical, unhinged.

But Cassandra was right.

Jon Hauxwell, MD, is a retired family physician who grew up in Stockton and lives outside Hays.