These poor and vulnerable communities bear scant responsibility for the pollution driving climate change - but they are in the front line of its impacts.
England's flood defenses aren't getting nearly the funding they need to respond to climate change: particularly if you live in a poorer area.
Faced with the threat of invasion in 1940, Winston Churchill defiantly declared: "We shall defend our island, whatever the cost may be".
Today, faced with the threat of climate change, our leaders are pathetically pusillanimous. "We shall defend our island", they croak, "if the cost-benefit analysis stacks up."
The crumbling state of our defences was recently laid bare by the National Audit Office (NAO), in a new report on the state of England's flood preparedness.
"Current spending is insufficient", it states, "to meet many of the maintenance needs the [Environment] Agency has identified" for its flood defence assets. "This will increase the danger of asset conditions degrading, so increasing flood risk."
All this, the NAO warns, at a time when climate change is increasing flood risk. The result is that the Environment Agency will have to let maintenance of some flood defences 'lapse' - or put less euphemistically, 'collapse'. The government's auditors conclude, tersely, that "the achievement of value for money in the long term remains subject to significant uncertainty".
Their verdict is a damning indictment of government neglect. It comes after Ministers quietly admitted that flood defence repairs from last winter have fallen behind schedule; and after insurers wrote to the Chancellor demanding he plug the £500m shortfall in flood defence investment needed to keep pace with climate change.
Yet the case for climate action shouldn't have to come down to such a cold, calculating totting up of ledgers. The moral case for protecting people from rising seas and worsening floods is overwhelming.
Climate change is not something that has been caused by the people most affected by it. This is most patently true globally, when the world's poorest in sub-Saharan Africa and southeast Asia are set to suffer the brunt of climate change. But it is also true of how climate change will hit the British Isles.
A recent analysis by Oxfam showed that the most deprived English neighbourhoods have been three times more vulnerable to flooding than the most well-off in the past quarter-century.
The low-lying east coast of England, for example, is especially vulnerable to rising sea levels and storm surges, as witnessed last December when the worst tidal surge in six decades struck settlements from Essex to the Humber.
It is also an economically deprived part of the country, a coastline dotted with declining seaside towns often forgotten about by Westminster: the flood-prone town of Jaywick near Clacton, for instance, is the poorest ward in the country.
These communities bear scant responsibility for the pollution driving climate change - but they are in the front line of its impacts.
Flood defence money follows the money, not the need
All this is lost in the cold budgetary calculations of Whitehall. The Treasury enforces a system of payments for flood defences that places weight on the economic value of the properties being protected. Richer, urban areas inevitably attract more cash; poorer and smaller settlements get less.
The Chancellor's latest wheeze is to oblige local businesses to chip in to the cost of flood defences whilst he cuts the public sector contributions. Make businesses pay by all means, but this will only exacerbate the inequality of flood protection: poorer communities with fewer businesses will simply not get defences.
Tellingly, the only part of the country where there is a legal duty to build flood defences is - yes, you guessed it - central London. Protect the metropolis; the rest can swim.
Alarmingly, the communities whose flood defences have been left to crumble may not even know the risks they are being exposed to. The report by the NAO states that the Environment Agency "has not communicated to communities the local effect on future flood risk from the de-prioritisation of maintenance in some areas."
If true, this is genuinely shocking. But it wouldn't be a great surprise if the communities being quietly neglected were more deprived and far from London.
When last winter's floods struck, David Cameron was generous in his rhetoric, declaring that "money was no object" in helping people recover from the disaster.
Such apparent largesse meant little, however, coming after years of cuts to the flood defence budget - cuts that have clearly affected the state of our country's defences and left them in a more fragile state.
Needed now - a £500 million investment
The Coalition needs to invest £500m to keep pace with climate change; the cost of last winter's floods has already run to at least £1bn. To take a cost-benefit approach, it would have been better to invest in maintenance earlier, rather than have to pay out much more to mop up the mess later.
Yet even if the numbers did not stack up so clearly, there would be an overwhelming moral case to protect the whole country from climate change.
The more fossil fuels we burn, the more it will flood; the more we neglect our defences and force households to fend for themselves, the more the poorest will suffer.
We must prevent climate change getting any worse, and we must protect society from its impacts - the whole of society - not just those parts of it the Treasury deem most economically useful.
Guy Shrubsole is climate campaigner at Friends of the Earth. Previously he worked for the Public Interest Research Centre and the Department of the Environment, Food & Rural Affairs.
This article was published by Open Democracy under a Creative Commons Attribution-NonCommercial 3.0 licence.