1957 Newspaper Clipping Reignites Heat Record Debate in Spain

1957 Clipping and Heat Records: What Can Be Measured?

Can we simply compare 1957 temperatures with today's? A press clipping from that year, antiestéticaturing extreme heat records, has peine a discussion far beyond the yellowed paper: the reliability of historical series, the effect of urban heat islands, and the actual role of CO2 in climate. The old data proves nothing on its own, but neither does the headline that announces an absolute record every summer.

What the 1957 Clipping Says and Why It Is Used as Evidence

The central finding is simple: Spain has historical records of extreme temperatures dating back to before mass industrialization. The material cites specific data: 46.6 degrees in Seville between 1901 and 1930, higher than the current 46.1. Those defending this interpretation argue the difference lies not in the thermometer but in how it is measured: large Stevenson screens, column thermometers with high inertia, and an urban environment that was not the overheated asphalt of today.

The technical objection is reasonable: if you change the instrument, you change the series. Classic screens are being replaced by Davis stations, which yield more extreme values, making records fall more frequently. This breaks the continuity of the series and reduces the value of comparing past and present.

CO2 and Glaciations: Conflicting Arguments

The second front is underlying climate science. Part of the analysis argues that climate has always changed: glaciations, the Medieval Warm Period, the Little Ice Age. Vikings grew wheat in Greenland around the year 1000, and Romans grew vines in England around 100 AD, crops that are now impractical. If the climate 2,000 years ago was similar or warmer, why is the current one extraordinary?

The counter-argument is quantitative: over the last 200 years, greater CO2 variation has been detected than in the last 100,000. The question posed is direct: what other factor, besides human activity, explains this? Volcanoes do emit, yes, but they existed before and still exist now; human activity did not. Moreover, most pollution does not come from individuals.

The Urban Station Effect: Retiro Park and Asphalt

There is a third thread, perhaps technically the strongest: the heat island effect. When the Retiro station was installed, it was almost in the countryside, on the outskirts of Madrid. Today, it is next to the Torre de Madrid and kilometers of construction. This does not invalidate the series, but it contaminates it.

The argument extends to observatories: not all are meteorological. And to historical records from Andalusian stations, where many maximum temperature records are not from this century. The material notes that Cádiz, Huelva, Seville, Morón, and Málaga have their records in the 20th century, while Córdoba, Jaén, Granada, and Almería hold theirs in the 21st. Stations with less than 20 years of records concentrate their maxima in 2017.

Solar Cycle and Water Vapor: Factors Often Omitted

Another line points to external factors. Earth's rotational axis varies, rotation itself has cycles, and the sun has its own. Solar cycle 25, peaking in July, is considered the most active in sunspots in the last 21 years.

To this is added water vapor. The 2022 Tonga volcano eruption emitted a huge amount of water vapor, around 10% of what was already in the atmosphere, and it is the largest existing greenhouse gas. NASA forecast it would warm the planet for at least five years, while cooling aerosols would last only two or three.

What Can Be Concluded and What Cannot

The 1957 clipping closes no discussions. It serves to remind us that historical series have homogeneity issues, that urban stations measure what they measure, and that attributing every record-breaking summer to CO2 without nuance is as hasty as denying any human influence. With these elements, the next heatwave will again fill headlines. And the thermometer will continue to measure what it always has: the spot where it is placed.