Are heat spikes more common today than they were fifty years ago? A hundred years ago? Two hundred?
An interesting question. An even more interesting one is this: how far back does our temperature record truly go, and how much confidence should we place in what we think we know about it?
Yes, temperature measurements existed a century ago. In some places they existed much earlier. Thermometers are hardly a modern invention. But the existence of measurements and the existence of reliable, comprehensive data are not the same thing.
The instruments were cruder. Calibration standards were inconsistent. Observation methods varied wildly from place to place. Data collection itself was a completely different enterprise.
How many measurements were taken per day?
At what times?
Were they standardized?
Were they adjusted later?
Did anyone record changes in the surrounding environment?
A thermometer standing in an open field is not measuring the same environment decades later if a city has grown around it. A station once surrounded by farmland may now sit amid concrete, asphalt, buildings, traffic, and industrial activity. Yet we often speak about temperature records as though they emerged from some pristine laboratory untouched by history.
Reality is rarely so accommodating.
The internet is a little over half a century old. Yet even that comparison reveals how quickly things change. The early internet bears almost no resemblance to the system we use today. For most ordinary people, the internet did not truly become part of daily life until the late 1990s.
That gives us perhaps thirty years of widespread digital data collection.
Thirty years.
To generate the kind of dense, continuous, high-frequency measurement networks that modern analysts take for granted, you need infrastructure. You need sensors. You need communications systems. You need storage. You need standardization. Above all, you need scale.
Most of that barely existed until recently.
In fact, humanity has produced more data in the last decade than in all previous centuries combined. We are drowning in information today. Sensors monitor oceans, cities, forests, power grids, aircraft, satellites, vehicles, industrial facilities, and countless other systems around the clock.
And yet even now our picture remains incomplete.
Entire regions of the planet remain poorly monitored. Oceans cover most of Earth’s surface and remain difficult to measure comprehensively. Vast stretches of wilderness still produce sparse datasets. Data gaps remain everywhere one cares to look.
That is the situation today, with all our technology.
Now imagine trying to reconstruct the climate of a century ago.
Or two centuries ago.
Or before the Second World War.
The further back we travel, the more the record dissolves into fragments. We have observations, certainly. We have clues. We have snapshots. We have logs, journals, station records, ship measurements, and proxies of various kinds.
What we do not have is anything remotely resembling the dense digital world of observation we enjoy today.
The past is not a crystal-clear photograph.
It is a mosaic assembled from broken pieces.
Useful? Absolutely.
Interesting? Certainly.
Precise enough to support absolute certainty about every modern claim? That is a far more difficult proposition.
For the last thirty years, perhaps we can speak with a reasonable degree of confidence. The data are extensive, frequent, and increasingly standardized.
Before that, confidence becomes progressively more expensive.
The picture grows blurrier.
The margins of error widen.
The assumptions multiply.
And once we move back before the middle of the twentieth century, much of what passes for certainty begins to resemble educated guesswork layered upon educated guesswork.
That does not mean we know nothing.
It means we should remember how much of our knowledge rests upon reconstruction rather than observation.
A society intoxicated by certainty dislikes hearing that.
Yet history has a habit of humbling those who confuse estimates with facts.
The climate debate is no exception.
The deeper we peer into the past, the more we discover that history is not a photograph. It is a fog bank.
And fog has a remarkable tendency to make distant objects appear far clearer than they really are.