If there is such a thing as an onward march of human progress, it has not just halted, but screeched into reverse. Last autumn, a little-discussed report issued by the United Nations noted that human development had declined in 90% of countries for two years in a row, a fall without precedent for more than three decades. The pandemic and Russia’s invasion of Ukraine played their role, but so too did “sweeping social and economic shifts, dangerous planetary changes, and massive increases in political and social polarisation”. You may well be familiar with chatter about “the decline of the west”: it has tended to be the preserve of the reactionary right, who blame, variously, moral decay, multiculturalism and a reassessment of European history for our downfall. But it is not minority rights, diversity or acknowledgment of western crimes to blame. The turnaround in our collective fortunes has been dramatic. But it is driven by an economic system that promised personal freedom but instead delivered insecurity on a mass scale, and which has has hurt us in every conceivable way, from our emotional and physical wellbeing to our material circumstances. Take one basic measure: life and death. The UK government has been forced to delay lifting the state pension age after a fall in life expectancy without precedent since the war. Although certainly worsened by the pandemic, life expectancy was already declining in many English communities years before Covid arrived on our shores. In the US, life expectancy declined from nearly 79 in 2019 to 76 two years later, the biggest fall for a century. And the morbid symptoms of a crisis in wellbeing are everywhere. Across the Atlantic, the suicide rate soared by 30% in the first 20 years of the 21st century. As the “war on drugs” has escalated, so have deaths from substance abuse: in the US, they have grown exponentially since the 1970s, helping to drive the fall in life expectancy, while in the UK they have reached their highest level since records began. Karl Marx once described religion as the “sigh of the oppressed creature”: today this is more of an apt description of drug addiction, driven by the self-medication of those afflicted by trauma and misery. Indeed, it is difficult to disentangle from a global leap in depression, which increased by almost a fifth between 2005 and 2015, and has also surged among US teenagers. Peering at the rubble left by humanity’s bloodiest war the best part of a century ago, a western European citizen in 1945 would have been pleasantly surprised to discover that the most prosperous years in history awaited them. Such was the unprecedented rise in living standards in the west in the three decades after the war that it became christened the “Golden Age”; for the French it was the “30 glorious years”. But while the UK suffered a particularly pronounced fall in wages in the 2010s, they have stagnated across the western world. Before the pandemic hit, the purchasing power of US workers had barely shifted for four decades. It’s easy to be lulled into the illusion that dramatic progress is still happening. Computer chips get ever-smaller; computer processors ever-faster; mobile phones ever-more dynamic. But technological advancement does not automatically translate into improvements in the human condition. Across much of the west, stagnation and decline has become the defining feature of our age. If you want to understand why politics became angrier and more polarised, don’t look for facile explanations such as argumentative behaviour fostered by social media. A grand experiment has been under way for more than a generation: what if you cut off optimism from rich societies that previously took ever-rising living standards for granted? The rise of the “free market”, we were promised, would unleash endless prosperity. But while the much-demonised age of strong trade unions, nationalisation and expansive welfare states delivered the greatest improvement in living standards in history, our current economic model is decomposing all around us: the stench is becoming harder to ignore. On both sides of the Atlantic, economic growth has fallen since the frontiers of the state were rolled back, and that more limited growth is more likely to be sucked into the bank accounts of the gilded rich. How does that explain, say, falling life expectancy driven by rising opiate use in the US? We know that the disappearance of secure, well-paid jobs has bred the conditions of misery in which addiction thrives. Growing inequality has helped spur on deteriorating mental health: rates of depression correlate with low income, for example. From the generational collapse in public housebuilding to the decimation of social care, the security that underpins a comfortable human existence has been peeled away. And yet how little this halt in human progress is mentioned, let alone debated. With our civilisation facing multiplying existential challenges, how quickly stagnation and decline could become a freefall. You don’t need an overactive imagination to ponder the brutal possible consequences, especially if progressive politicians fail to offer compelling answers. Our lives are shortening, our wellbeing is falling, our security being dismantled. These are the conditions of despair, and a bitter harvest beckons. Owen Jones is a Guardian columnist