Climate change did not suddenly become relevant in the twenty-first century.
Nor is it a phenomenon unique to the industrial age.
Anyone with even a passing interest in history quickly discovers that climate has been one of civilisation’s most persistent architects—and one of its most ruthless executioners. It has raised kingdoms, shifted populations, altered economies, and contributed to the collapse of societies long before humanity possessed either coal-fired power stations or internal combustion engines.
The Bronze Age Collapse is perhaps the most famous example.
It no longer belongs merely to the realm of archaeology but to the foundations of historical understanding. Around the end of the second millennium BC, much of the eastern Mediterranean world descended into chaos. Great kingdoms disappeared. Trade networks fragmented. Cities burned. Entire political systems that had endured for centuries vanished with astonishing speed.
The Sea Peoples remain one of history’s enduring mysteries. We still debate precisely where the different groups originated and how they organised themselves. Yet the broader picture has become increasingly clear. A combination of interacting pressures—including prolonged climatic stress, drought, food shortages, migration, political instability, and conflict—helped unravel the Bronze Age world. The Hittite Empire disappeared. Much of the Levant was devastated. Even Egypt, among the greatest powers of antiquity, survived only after enormous strain.
Climate was not the only actor on the stage.
But it was unquestionably one of the principal forces shaping the drama.
Nor was that the only time climate left its fingerprints upon civilisation.
The archaeological record across Greenland, Scandinavia, Iceland, and other North Atlantic regions tells another remarkable story. During the Medieval Warm Period, communities expanded into areas that offered comparatively favourable conditions for agriculture, grazing, and settlement. Life flourished in places that would later become increasingly marginal.
Then the climate shifted once more.
Temperatures declined.
Growing seasons shortened.
The Little Ice Age arrived, not as a single dramatic event, but as a prolonged period of cooling that profoundly altered living conditions across much of the Northern Hemisphere. Settlements contracted. Some disappeared altogether. Communities that had adapted to one climate found themselves confronting another.
Nature had quietly rewritten the rules.
The Roman world offers yet another chapter.
Historical records, agricultural accounts, and environmental evidence suggest that the Roman Warm Period provided relatively favourable conditions for farming across large parts of Europe. Crops prospered in regions that later became far less productive as temperatures declined during Late Antiquity and the early medieval centuries. Agricultural patterns shifted. Viticulture retreated in some northern regions. Farmers adjusted to climates that no longer resembled those their grandparents had known.
The archives remain.
The evidence remains.
The landscape itself remembers.
None of this should be remotely controversial.
Warm periods have occurred.
Cold periods have occurred.
They have alternated throughout recorded history and for countless ages before recorded history existed. Long before *Homo sapiens* appeared. Long before our ancestors first walked upright across African savannahs. Long before mammals evolved. Indeed, Earth’s climate has changed throughout much of the planet’s geological history, driven by a wide range of natural processes operating over vastly different timescales.
The further back we travel into deep time, the less precise our picture inevitably becomes. Geological records grow more fragmentary. Resolution declines. Uncertainty increases.
That is simply the nature of historical reconstruction.
The last three thousand years, however, belong to a very different category.
Here we possess written records.
Tree rings.
Ice cores.
Lake sediments.
Pollen analyses.
Glaciers.
Archaeology.
Historical harvest records.
Contemporary observations.
Multiple independent lines of evidence converge to reveal a climate that has never been perfectly static.
There is, of course, vigorous scientific debate about the relative roles of natural variability and human influence in recent climate change. That debate should proceed on the strength of evidence, not slogans.
What is beyond serious dispute is that climate has always changed—and that those changes have repeatedly altered the course of human history.
On that point, we are not speculating.
We are remembering.