On a calm and beautiful morning off the coast of south Devon last week, I was watching a small pod of dolphins from my kayak. I had spotted them from half a mile away, feeding and playing on the surface. They were heading my way, so I sat on the water and waited. But from round the headland, at top speed, came a giant twin-engined maritime wankpanzer. Though the dolphins were highly visible and it had plenty of time either to stop or avoid them, it ploughed towards them at full throttle. As it passed, missing them by a few metres, the driver turned and glanced at them, but never checked his speed. The dolphins dived. They briefly reappeared much farther from the coast, after which I didn’t see them again. I could hear the boat long after it disappeared: it sounded like a jetliner. God knows what distress it might have caused the dolphins, which are highly sensitive to sound. I was overwhelmed by two sensations. One, obviously, was disgust. The other was puzzlement: where’s the joy? If there is one thing that almost everyone loves and – if they’re lucky enough – delights in seeing, it’s dolphins. I don’t know anyone who wouldn’t stop and watch. Though I’ve experienced this good fortune dozens of times, because I’m so often at sea, I never cease to find it thrilling. The elation stays with me for weeks. But to the driver of that boat, it seemed, the sea was just a highway on which to race towards the horizon. It reminded me of something I’ve seen many times: the deadening effect of wealth. To own and run a 35ft boat of that kind, you need to be extremely rich. It retails at about £300,000, on top of which are the extraordinary costs of mooring, winter storage, maintenance and fuel. Isn’t money of that kind supposed to buy you pleasure? If not, what’s the point? Extreme wealth can severely hamper enjoyment. As Michael Mechanic documents in his book, Jackpot, there are two groups of people who have to think about money all the time: the very poor and the very rich. Immense wealth possesses you just as much as you possess it: managing it becomes a full-time job. You don’t know whom to trust; you can start to imagine your friends aren’t friends at all; it can dominate and poison your family relationships. It can hollow you out, socially, intellectually and morally. But I think there might be a further corroding aspect of wealth that hasn’t been widely discussed. Great wealth flattens the world. If you can go anywhere and do anything, everything is over the horizon. You speed past the local and the particular, towards an endlessly escalating ideal of luxury: the better marina, the bigger yacht, the private jet, the super-home. The satisfaction horizon can retreat before you. Place has no meaning, other than as a setting that might impress the friends you no longer trust. But anyone who is impressed by money is not worth impressing. There also seems to be a connection between speed, noise and ego. There must be something unresolved about a person who feels the need to fill the sky with noise and capture the attention of everyone he passes, whether he is on the road or the water. And yes, it is almost always a “he”. Studies show an association between traditional concepts of masculinity, speed and dangerous driving. It’s unsurprising that attempts to restrain driving behaviour, such as speed cameras and low-traffic neighbourhoods, have become such potent themes in the culture wars, animated by perceived threats to traditional gender roles and power relations. Travelling by kayak, I cover less sea and must stay closer to the coast than the people racing past in powerboats. But I have an intimacy of connection with the places and living systems that surround me, with the sounds of nature, with signs too subtle to see at speed – sandeels stippling the surface, the dorsal fins of bass pursuing them, holographic sea gooseberries suspended in the water column, cowries eating star ascidians on the rocks exposed at low water – of which they are likely to be deprived. I cannot imagine that the dolphin disperser was enjoying himself more in his £300,000 megaphone than I was in my kayak, bought secondhand for £300. Why? Because I cannot imagine any greater joy than I experience at sea. I’ve met quite a few very rich people. Some are lively, curious and engaged, but among others I’ve repeatedly noticed the same thing: a dullness of spirit. There’s a sense that nothing is sufficiently stimulating to hold their attention, that they have lost their capacity for wonder. That roaring boat proclaimed its owner as among the winners. But what can you call someone who cannot enjoy the sight of dolphins, if not a loser? For the fantasy of transcendence, of escape from connection with other lives, we are torching our life-support systems. We consent to the Earth-eating, soul-sucking mode of exploitation we call capitalism because we believe, quite wrongly, that we are all temporarily embarrassed millionaires. One day we too might live the affectless life of the ultra-rich. It is astonishing how much we concede to them. Down the coast in Salcombe, a painter-decorator friend finds much of his work endlessly renovating second homes. They’re empty for most of the year. But, he tells me, his clients leave the heating on, and often the lights as well, to create the impression that someone is at home. Three years ago, this district declared a housing crisis, yet still we allow the very rich to snap up local homes and leave them empty, while burning fuel as if there’s no tomorrow. Just as that boat owner scattered the dolphins, the very rich break up communities, deprive people of housing and threaten, ultimately, to drive us all out of the human climate niche – that is, the temperature range that enables us to flourish. We should seek a wealth of community, of knowledge, of wonder, of life, of love: a wealth that does not impoverish others. We should seek not private luxury, but private sufficiency and public luxury. But, as angry, empty billionaires bankroll Donald Trump, we might be about to discover how much harm they can do us. Democracy, a fair distribution of resources, peace of mind and a habitable planet all depend on restraining the power of the very rich: their noise, their occupation of our common space, and their intrusion into all we hold dear. George Monbiot is a Guardian columnist