There are places where measuring the local weather almost seems like a waste of effort. A weatherman in Los Angeles once showed viewers a picture of (what he said was) his personal automobile’s license plate, reading MCAFHAS – because, he explained, on almost every work day his job was to stand in front of a camera and say “Morning clouds and fog, hazy afternoon sun.” If the measure of information is its “entropy” (informally, its ability to surprise), then Fritz Coleman’s forecasts were (by necessity) mostly uninformative. No fault, just a fact – and perhaps the inspiration for Douglas Adams’s fictional planet Ursa Minor Beta, which “consists almost entirely of subtropical coastline,” and where “it is nearly always Saturday afternoon just before the beach bars close.”

Contrast this with weather coverage in Seattle, where local evening news usually opens with a one-sentence summary of the weather; then gives a more detailed assessment and forecast around twenty minutes in; then concludes with another one-sentence coda before they roll the credits. Three weather reports in thirty minutes? When location and geography make the weather’s entropy high, the potential information value of forecasts is likewise – and as climate change accelerates, the world is starting to feel a lot more like Seattle. Keeping track of rapid and complex changes, and getting a lot smarter about anticipating what’s to come, are increasingly important – but fortunately, becoming more affordable with improved technology.

For those who want tech that can monitor weather simply at minimal cost, a “magic weather rope” is a facetious option. You can make your own, or you can get a professionally finished version from La Crosse, whose “handcrafted in the USA” version of this classic tool includes a helpful plaque of instructions for interpretation:

IF THE ROPE IS:
Wet…….Rainy
Moving…Windy
Hot…….Sunny
Cool…..Cloudy
Stiff……...Cold
White….Snowy
Gone…TAKE SHELTER

As a measuring tool, the magic rope has the advantages of low cost, ease of operation, and simplicity of presentation. Its disadvantages, though, are considerable, including possible confusion—in freezing rain, it may be difficult to characterize the “output”—while time lag (how long does it take a wet rope to dry when the sun comes out?) will limit the value of observations. These defects, unfortunately, are not limited to the realm of gag gifts; as it turns out, measurements that were easy to make in much less whimsical studies have also turned out to be misleading.

For example, ocean surface temperature is easy to measure: systematic records go back to at least as early as the 1850s, and considerable effort has gone into making comparisons meaningful despite differences of equipment and technique. To some degree (pun accidental but apropos), however, this has been a diligent effort to do the wrong thing well – because there are hundreds of years of records of deeper seawater temperatures preserved in the growth bands of sclerosponge skeletons. Measurements of these “demonstrate that industrial-era warming began in the mid-1860s,” which may seem merely historical, but further analysis suggests that “global warming was already 1.7 ± 0.1°C above pre-industrial levels by 2020”; the researchers emphasize that “Our result is 0.5°C higher than IPCC estimates, with 2°C global warming projected by the late 2020s, nearly two decades earlier than expected.” This seems worth knowing.

Further, sticking with a theme of “deeper measurement is harder but worth the effort,” it also turns out that measuring air temperature is easy – but measuring temperatures under the surface of the earth yields importantly different results. Writing in the journal Nature Climate Change, researchers in Germany shared findings in 2023 that “soil hot extremes are increasing faster than air hot extremes by 0.7°C per decade in intensity and twice as fast in frequency on average over Central Europe.” Digging even deeper (sorry, another unavoidable pun), an overlapping team of researchers reported just last month that

Soil heat extremes increase faster than air heat extremes across a majority of sites, with spatially averaged trends showing that the annual maximum 7-day mean temperature increases by 0.78°C/decade in soils compared to 0.56°C/decade in air, while the frequency of hot days above the 90th percentile (TX90p) rises by 9.33%/decade in soils versus 1.27%/decade in air.

Notable and troubling is the researchers’ observation that “Particularly strong amplification is present in temperate continental climates and dry sub-humid regimes, consistent with reduced evaporative cooling under recurrent soil drying.” In other words, there are cumulative effects that make recovery more difficult with every passing year – as discussed in more depth (oops) in a note here two months ago, specifically sharing findings that “The world's rainfall is increasingly packed into bigger storms with longer dry spells in between, and a lot of rain all at once causes problems for overwhelmed soil.”

Finally, because it’s runaway feedback loops that may matter most, research from China reported last year found that

Particularly in Northeast China, the increasing trend for soil extreme heat is nearly double that of air. In this context, the intensified soil extreme heat is markedly accelerating soil respiration rates, with a remarkable increase of 33.6% reported in North China. This further enhances carbon dioxide (CO₂) release, with forest and agricultural ecosystems identified as significant contributors to carbon emissions in Northeast China. Furthermore, the impact of rising soil extreme heat on air temperatures is projected to intensify in the future, especially in North China, which is expected to increase by 30% as the global temperature escalating from 1.5 to 2.0°C. Future increases in soil extreme heat intensity could further enhance soil respiration, exacerbating CO₂ emissions and accelerating future warming.

I’m reminded, by these examples, of a moment in the movie “The Core” when the story requires intrepid scientists to venture down to the center of the Earth. When someone says that this will be impossible (plot spoiler: in the movie, he’s wrong), an authority figure starts to say that “If we can go into space…” – and he’s rebutted with the comeback that “Space is easy. It’s empty.” In the real world as well as in the movies, it’s easy to do things in the places that are empty – but that’s not where we’ll learn what we probably need to know.