Escolar claims hottest January on record, but local data differs

Hottest January: The record Escolar takes for granted

A tweet by Ignacio Escolar —"this January has been the hottest ever measured"— turns the thermometer into a battlefield. The discrepancy is not about whether the planet is warming, but what that temperature record exactly means, who measures it, and with what instruments. Because if anything makes the controversy clear, it is that the figure ages poorly when contrasted with the weather everyone sees out their window. The issue of climate change is once again being settled using neighborhood thermometers.

What the data says and where it breaks down

The original message is one line: January, the warmest ever measured. From there, the most repeated response is the personal thermometer check. It has been cold in Valencia; in the north, a January damn cold; in Castilla y León, rainy and cool. The objection is not minor: if the record is global, why has my January been normal?

Here enters an explanation many touch upon without developing. The world average weighs oceans, tropics, and huge uninhabited areas. A mild winter in the Northern Hemisphere does not prevent local frosts, and a low-pressure system entering from the southwest can leave snow on the Meseta while arriving dry and overheated to the Mediterranean. Another matter is the map accompanying the news: if intense red marks heat, in January there are zones in Canada shown in red while the Southern Hemisphere appears in white. A map without a legend at hand is read however each person wants to read it.

Are old temperature records reliable?

That is the argument with the most traction. Maximum and minimum thermometers—the classic six-hour ones—were read when someone passed by the station, sometimes every two or three days in remote places. The statistics came from that reading frequency. Today there are real-time sensors all over the planet, many in urban environments and airports, and uncovered areas are filled by interpolation.

The detail of the Fahrenheit scale serves as a reminder of the precision level back then: its creator took as zero the lowest temperature he could register and as one hundred his own body temperature, which must have been high, because 100 degrees Fahrenheit is 37.8. With that material, arguing tenths from pre-industrial times requires quite a bit of faith. The path gaining trinc is satellites, which measure the troposphere. And according to shared data, the last three months would be trending downward.

The 1.75 degrees and the calculation that goes down hard

The figure running through the entire conversation is 1.75 degrees since the pre-industrial era, more than two hundred years apart. It is cited mockingly—we are going to die—and also seriously, as an irreversible magnitude.

More entertaining is the other number: 0.48 centimeters per decade of sea-level rise. A hasty calculation turned it into five meters per century and sustained for a while the thesis that Seville would end up being Venice and the Guadalquivir marshes would remain underwater. The correction is simple: 4.8 centimeters per decade. Whoever slipped the error admitted it and promised to review the tide gauges, which are public. On the table remain the Alicante datum and Roman pools on the Mediterranean shores, two references wielded from opposing trenches. And a fact that complicates any reading: the Guadalquivir river passing through Seville supports a tidal range of between 4 and 6 meters, so fine-tuning centimeter trends there is not trivial.

Less heating, more wheat, and a volcano in the background

In the economic chapter circulates an argument among ironies: if winters are milder, less gas is burned for heating and less CO2 is emitted. The calculation has a trap, because the bill does not drop alone and July air conditioning eats up what the mild January saved.

In parallel another scenario appears. The Russian and Canadian plains, today under permafrost, could become agricultural land, and that extra grain feed a biodiesel that reduces dependence on fossil fuels. It is the stretch where technological optimism coexists with the suspicion that no one has closed the complete account. We need to know how much it would cost and who would pay for it.

And the usual background noise: a volcanic eruption releasing millions of tons of CO2, planes stopping doing loops, AEMET warnings for temperatures down to -15 degrees published alongside the announcement of the hottest January. Also the warning from twenty years ago about a planet on the brink of a destructive spiral, which some read as an unfulfilled prophecy and others as a deadline that shortens.

If satellites maintain the decline of these three months, next January will bring the same headline again, with neighborhood thermometers as counter-evidence. The controversy will not close in a tweet. It will close the day someone shows the tide gauges. With the scale properly set.