If modern lives were measured in unprecedented weather events, we would all be 200 years old. Defences against floods that were supposed to happen every other century are being overtopped in the space of a few winters. The victims surveying ruined homes and businesses are ageing fast.

David Cameron is not a figure to whom, these days, they should turn for consolation. Scotland’s ministers are also edging towards the truth. Given what we already know from bitter experience of changing weather, a harsh political climate has begun to prevail. Protection for some communities can no longer be guaranteed. Limits are being reached.

The Prime Minister can talk of millions spent and billions on the way, but those who have seen the worth of previous efforts, some of them just completed, are glimpsing reality. The latest unprecedented floods rose higher than the last unprecedented floods. “Record-breaking” rainfall has washed away the last record-breaking statistics. And the proposals for the future sound as flimsy as the defences.

It is some sort of joke, lost on those wading in the bog that was once a front room, that all this has happened while a grand conference in Paris haggles over words that might prompt the world’s governments to act on climate change. The task is fiendishly difficult, of course. Few in Hawaii spend any more time thinking about floods in Hawick than Hawick spends contemplating tropical storms, submerged islands, or droughts in far-off lands. Nevertheless, explanations will no longer do as excuses.

People want protection in their homes, far less their own backyards. They regard that, reasonably enough, as a government’s job. Yet from the devastation in the Borders, Cumbria and beyond a message has emerged: the challenge cannot be met. Mr Cameron’s administration can and should be denounced for the effect of spending cuts on emergency services. Sheer, casual negligence would be the charge. The real issue, though, is far bigger than that argument.

You could hear as much this week in the official voices insisting, time and again, that new defences were – contrary to appearances – successful. In essence, we were being told that things could have been very much worse. Does that help? Logic says, after all, that if the next deluge is worse still, the failure of “successful” schemes to defend communities will be greater. How high do walls and embankments need to be? No one can say. How much would they cost? No one really knows.

The flood-proofing, so called, of buildings sounds like common sense. It generally counts as a way of mitigating damage rather than averting inundation – rip out wooden floors and pour concrete, raise sockets, re-site drains – but it is probably better than nothing. Yet who pays? Owners, house builders, insurance companies, the state? Take a guess.

Sensible advice to avoid building on flood plains is also rather less impressive than it was even a few years ago. The “at risk” category is growing steadily, after all. Communities for which floods were once ancient history have been washed out repeatedly. Those who argue, meanwhile, that floods must be allowed to happen where nature might intend (generally over farmland) are also a little blithe. Criticise the farming industry as you will. Food security is another issue of the age.

If it is truly a choice, in any case, between wrecked farmland and wrecked homes, things are more urgent than the public has realised. If one town’s flood protection scheme is simply creating floods for another town downstream, even sophisticated plans begin to sound inadequate. The issue of where to site new housing is one thing. Hawick and Keswick and Cockermouth are not new towns.

There is a sense now of retreat. No government still pretends that the entire coastline of the British island can be defended against increasing erosion. Some who are expert call, in effect, for the abandonment of swathes of farmland as floods persist and spread. It will not be long, surely, before someone, probably in the insurance industry, contends that whole communities will have to be left to the elements. How many more assaults can the worst-afflicted endure?

Meanwhile, Mr Cameron promises the usual compensation while his government (says No 10) will “look again at the level of rainfall”. Labour retorts that flood defence management budgets were cut by 14 per cent last year in England and Wales. The charge is damning, yet the sums involved, set against the reality of risk, are trivial. It amounts to an inadvertent confession: the real cost of climate change is one that Britain, north and south, is neither able nor willing to meet. The real cost is vast.

So we’ll frack instead, if Mr Cameron has his way. Anyone who hasn’t made the connection between the latest quick-money energy scheme and the shutting down of the Peterhead carbon-capture project, the cuts to renewables subsidies and the effective ending of energy efficiency programmes has not been paying attention. Despite all the Prime Minister’s fine talk of yesteryear, his Government is fully committed – and will rig planning laws to get its way – to fracking, to quick and dirty fossil fuel extraction. Does the Scottish Government take a different view? We’ll see.

Were they honest, all the distinguished heads of state who have turned up in Paris would have disreputable stories of their own to tell. A global effort to at least stabilise the climate is being undermined, as ever, by the political dishonesty that calls itself pragmatism. Misery in Hawick or Cockermouth is no way to teach ordinary people about the need to keep fossil fuels in the ground, but the floods at least involve a truth that cannot be ignored.

“The weather” does not grow less malign just because the Met Office gives a storm a silly name. The cost for too many people – and for all governments – is no longer abstract. The remedies proposed by hydrologists and civil engineers no longer qualify as panaceas. The gloomiest of environmentalists will tell you that, for communities across the world, flooded, desiccated, submerged or swept away, it is already too late. So which elected politician fancies telling voters that this is just the way it has to be?

It would be petty point-scoring, of course, to ask what the Government reaction would be if the Thames Barrier failed. On the other hand, it is possible to wonder about just what it might take to change official habits of mind.

The excuse that emissions from these islands are trivial besides those of the big polluters has been perfect for governments in countries big and small. Those who still deny a human effect on climate play their witting part in mass distraction. Year by year, the waters return, worse than before.

Mercifully, we do not suffer the vast disasters endured in some countries, but for victims the winter floods are bad enough. Worse, perhaps, is the realisation that everything being done to make their future secure is far too little; and far too late.