Jared Diamond has won renown as a polymath of incredible versatility: a biologist, geographer, linguist and historian. While his environmental approach to big-picture history is suggestive of cool, white-lab-coated detachment, Diamond also wears the mantle of a modern day prophet. Only the most obtuse reader of his latest book, on national resilience, could miss the signs and portents with which it is studded.

Diamond’s analysis of the ways in which half a dozen modern countries that he knows well – Finland, Chile, Indonesia, Japan, Germany and Australia – have coped with crises, is shot through with reflections on the fragility of democracy. It explores the imperatives of taking responsibility (without scapegoating), honest national self-appraisal, a willingness to learn from other nations and a capacity to compromise, sometimes, indeed, to swallow the unpalatable.

Consider the parable he relates about Finland. Throughout the cold war, “Finlandisation” was a term of abuse in the west for complicity with the Soviet Union. Under the long rule of two ultra-cautious presidents, Juho Kusti Paasikivi and Urho Kekkonen, between 1946 and 1981, the Finns did things “unthinkable in any other democracy”, such as engaging in self-censorship, postponing a presidential election and pressuring one unacceptable presidential candidate to withdraw. Why? Because during the second world war the Finns had fought alone against an invasion by the Soviet Union that gobbled up the region of Karelia (including Finland’s second city of Vyborg), and then found themselves on the wrong side at the war’s end. Finlandisation began right away when the Finns – under allied pressure – tried their own wartime leaders for war crimes. Diamond recognises the brute realities of the country’s geographical proximity to Russia and the costs of a war that took the lives of 100,000 Finns. Not a huge figure, it might seem, but amounting to about 5% of the male population. The Finns made massive sacrifices during the war to preserve their autonomy, and continued to make sacrifices of a cringing, craven sort in the postwar era. But what other option did they have? “A country’s independence is not usually absolute,” President Kekkonen reminds us. “There was not a single state in existence that did not have to bow to historical inevitabilities.”

The case of Chile serves as a sharp reminder that complacent self-congratulation offers no real barrier to democratic breakdown. When Diamond first visited Chile in 1967 the country prided itself on its stability and the relative docility of its army. In recent decades it had not been plagued by the frequent resort to military coups typical of other Latin American states. Yet within six years democracy was to be toppled by the military. Diamond’s Chilean friends expected military rule to be a brief, temporary measure, but the government of General Pinochet lasted from 1973 to 1990. Moreover, the regime was one of unparalleled brutality in South America, resorting to mass killings and torture at home, and in 1976 deploying a car bomb to assassinate an exiled Chilean dissident a mere 14 blocks from the White House.

Both Chile and Indonesia, where a curiously bungled communist coup of 1965 provided a convenient pretext for the army to kill around half a million Indonesians, show how the demonisation of political enemies can lead in some instances to plans for their extermination. Of course, where the army is unaccustomed to independent political action, fears of military coups are largely groundless; but the wide availability of firearms in the US, as Diamond notes, conjures up other chilling scenarios.

Facebook Twitter Pinterest In living memory … clothes of those who were killed in the Rwanda massacre, in 1994, are hung out in Kigali to mark its 25th anniversary. Photograph: Dai Kurokawa/EPA

Such things can happen in Europe, too. Incredibly, the social cohesion that underpinned Finnish self-discipline emerged in a society that as recently as 1918 had been riven by a civil war between Whites and Reds. Measured by percentage of the population killed per month, this was the world’s most lethal civil conflict until the massacres in Rwanda in 1994. The bonds of nationhood were, of course, reknit with amazing speed; but ponder too the obverse, that a robust national ethos is no insurance at all times against bloody polarisation.

Inevitably, the second world war induced reappraisal in several nations, not only in Germany and Japan, but also in Australia. A nation that had regarded itself as a British outpost began its gradual turn towards the US once it became clear that Britain could no longer protect Australia and fight a war against Hitler simultaneously. The Japanese bombing raid on Darwin on 19 February 1942 brought the message home, though the country’s sensible reorientation towards Asia would take decades.

Japan itself has only partially engaged in honest reappraisal. By contrast with late 19th-century Meiji Japan’s open-minded emulation of European industrial societies, today the country remains, in many respects, insensitively nativist, self-defeatingly so. Its reluctance to embrace immigration leaves its elderly citizens without the support of immigrant care workers found in other advanced industrial nations. Whereas postwar Germany eventually forged a new relationship with its neighbours based on honesty and contrition, Japan has yet to be open about wartime atrocities in China and Korea. Understandably, the necessary relationship that the offshore island state – perhaps any offshore island state – must have with its continental neighbours remains unsettled and riddled with suspicion.

Diamond’s checklist of factors that underpin national resilience is, however, of limited utility, as he recognises, when it comes to the problems faced by our small blue planet. We have little previous experience of coping with pan-global challenges, and, whereas nations often draw on external models when searching for solutions, humankind stands alone in the face of global warming, resource depletion and the threat of nuclear catastrophe. Nor do we share a common identity of the sort that allowed the Finns to pull together. Although there have been serious attempts to build global institutions – such as the League of Nations and then United Nations – the results have been patchy. Is humanity ready to engage in honest self-appraisal of the condition in which it finds itself? And are we then prepared for worldwide acceptance of responsibility for our plight?

Diamond has grounds for extreme pessimism, but he also sees some hopeful signs, in the work of international agencies to tackle specific issues, such as the eradication of smallpox, or the International Convention for the Prevention of Pollution from Ships. He is further impressed by the continent-wide levels of cooperation found in the EU, notwithstanding the inevitable teething problems associated with such a bold departure from the historic norms of statehood. Globalisation brings difficulties in its wake, yet, regardless of our human propensity to self-deception – so evident still in certain redoubts – it also brings a growing awareness of the interdependence of nations.

Diamond’s methods – drawing direct parallels between personal and national trauma, and between the psychology of individuals and character of nations – are not those practised by historians, who tend to emphasise the particularity of circumstance and the intricate unrepeatability of events. Diamond nonetheless plots in counterpoint the various predicaments he discusses, alert, in as non-deterministic a mode as he can manage, to the open textures of historical possibility. The prophet spares us chiselled commandments, but we have been warned.

• Upheaval: How Nations Cope with Crisis and Change by Jared Diamond is published by Allen Lane (£25). To order a copy go to guardianbookshop.com. Free UK p&p on all online orders over £15.