We are reaching a period of near-global militarisation. Military spending worldwide soared by 9% to a record high of $2.2tn last year and is likely to grow further in 2024, aided by Russia’s war in Ukraine and Israel’s assault on Gaza.

Against this backdrop, Rob Bauer, the chair of the NATO military committee and an admiral in the Dutch Navy, last month said that countries must increase their capacity to produce weapons and consider plans for mobilisation, increasing the size of reserve forces and even conscription.

This spending and messaging mean the world’s military-industrial complexes are looking forward to boom times in the coming years – and senior British politicians and military are as keen as any to help bring it on.

Defence secretary Grant Shapps last month warned that we are moving from “a post-war to a pre-war world” and must respond accordingly, while the head of the British Army, General Patrick Sanders, said the UK should take “preparatory steps to enable placing our societies on a war footing”, such a change being “not merely desirable but essential”.

Successive British governments have long bought into the idea that we have a significant, if not quite great, military power. The reality is different, though. The UK has been involved in four wars in the last two decades – and has a track record that is little short of disastrous.

The war in Afghanistan, where the UK was a close ally of the United States, began in 2001 and lasted two decades – killing an estimated 70,000 Afghan and Pakistani civilians, according to Brown University and The Watson Institute’s Costs of War project. The Taliban is now in control, with the human rights position being grim, especially for women and girls.

Yet that war is hardly mentioned in discussions on UK military policy, with the endeavours of Russian president Vladimir Putin serving as a useful distraction. This is also true of the 2003-2011 Iraq war – another conflict where the UK was Washington’s closest supporter and that went on for many years despite expectations that it would be over in months.

The death toll for that war is unclear, though the Costs of War project states that we know that between 280,00 and 315,000 Iraqi civilians have been killed by direct war-related violence since the US invasion – although it says the real figure is likely to be much higher due to deaths not being recorded.

Then came the disastrous intervention, along with the French, in Libya in 2011, which left the country wrecked and bitterly divided conduit for paramilitaries and armaments transiting south to the multiple zones of instability across the Sahel and on to eastern Africa.

Finally, the UK was closely involved in the four-year air war against ISIS in northern Iraq and Syria after the group staged its astonishing come-back in 2014, controlling large areas of both countries and even threatening to take Iraq’s capital, Baghdad. Some commentators argued that this war was successful, but ISIS is still waging a resilient insurgency throughout central and north-eastern Syria and is active – as are al-Qaida and other Islamist paramilitary movements – across northern and eastern Africa.

And now, the UK is supporting Israel’s increasingly controversial war on Gaza – which the Gazan health ministry reports has killed more than 28,000 people, many of them children, since October – and the US’s air war against the Houthis in Yemen.

Another problem for those calling for an expansion of the British military is its current state. is the state of the British military – which has made a vain and costly attempt to be a global power in recent years but faced multiple problems.

Two huge aircraft carriers, which are the Royal Navy’s largest ever warships and cost more than £3bn each, entered active service in 2017 and 2019 and their maintenance cost a reported £39m in 2020 alone. Both have been plagued with faults and in any case, there are not sufficient frigates, destroyers, support ships or crew for even one of them to be deployed globally except for short tours.

Meanwhile, the Trident replacement is beset by delays and cost overruns and is taking more than £200bn out of the military budget.

But perhaps the biggest argument against spending more money on expanding the British military is that doing so would be entirely irrelevant to the security problems ahead.

Accelerating climate breakdown is by far the greatest challenge facing the UK, along with every other country in the world – although you wouldn’t know it from all the debates over defence budgets.

The indications are now coming thick and fast. In the past week Chile has been trying to recover from wildfires around Valparaiso, a city in the country’s south, which have killed 131 people. Countries right across South America have faced similar blazes in what has been an exceptionally hot summer for many in the southern hemisphere, with last month the hottest ever recorded.

Even more worrying are the changes to the North Atlantic currents that are key to regulating the global climate, which a recent study found are being sped up by Greenland’s glaciers and Arctic ice sheets melting faster than predicted.

This will have “devastating” effects, the paper’s lead author said, including sea levels rising by a metre in some regions, including many coastal cities, the southern hemisphere becoming hotter still, and the Amazon’s wet and dry seasons being reversed.

Militaries will be increasingly used to protect borders, with the climate-related mass displacements likely to be viewed by many as a security threat. But all the warships in the world won’t stop desperate people trying to move to safer lands, and closing the castle gates isn’t much use if conditions within the castles become unliveable.

Somewhere, somehow, we have to engage in a fundamental rethinking of what security means for us as individuals, communities and, indeed, the whole world.