A crucial issue in climate science and policy is whether the world really is getting warmer and at what pace and, again, how do we know? In Australia there’s been quite the kerfuffle because the Bureau of Meteorology tried to hide the fact that newer temperature probes tend to record higher temperatures than older ones, and it took a series of Freedom of Information requests to pry the data out of them. Not that they have anything to hide, you understand. And now we have an item from an alert reader that we share to illustrate the sorts of problems that are hidden behind all those high-tech graphics of bright red oceans. “Unexplained Ocean warming alarms scientists”, the BBC blares (it’s also busy pumping out alarmist pieces like “Earth Day: How to talk to your parents about climate change” and even one urging further disruptive environmental protests “even if they are widely disliked by the public” as the revolt of the elites continues). But how do we know how warm the ocean used to be? Apparently by holding a thermometer in a breeze on a shipping lane. Not ideal.
No, really. Our correspondent is an old sailor and he explains that “Back in the days before satellites, meteorologists relied on merchant ships reporting weather conditions” and it was a highly organized affair: “ship’s officers were taught meteorology, and equipped with barometers and thermometers by the Meteorological Office, readings were taken every six hours and reported by radio.” But here’s the problem:
“The sea surface temperature was obtained with a special narrow rubber bucket, attached to a long line, which was thrown over the ship’s side to collect about a pint of sea water, it was then hauled in onto the bridge, where a thermometer was placed in the bucket to take the temperature. It is something I have done many times, and being right-handed I would hold the seawater bucket in my left hand, inserting the thermometer with my right hand, then after a few seconds I would pull out the thermometer and hold it in front of me to read the temperature, pouring the seawater out of the bucket with my left hand. Of course, I was reading the thermometer not when it was actually in the water but just after it had been taken out and was being cooled by the air.”
Oh dear. Note that this distorting effect, if real, would not have affected apparent trends during the period that it was done in this manner, nor geographic variations, because it would have been uniform. But when meteorologists appropriately switched to higher-tech and more reliable methods, well, you’d get one of those trend discontinuities just where you switch data series that ought always to raise concerns about it being a measurement artefact.
Not that the later methods were necessarily more reliable. A popular alternative method to using buckets was to take readings of intake water used to cool the engines. But here too the readings were distorted by being recorded after the water had been pumped into the ship’s interior. Whether that affected the trends is anyone’s guess—literally, since for large parts of the 20th century data sets the temperature record-keepers don’t know which method was used.
Now you know what the usual suspects will say. But as David Whitehouse points out in a temperate piece over at NetZeroWatch, the recent record ocean-temperature high (since 1981) is puzzling partly because “at this time of the year North Atlantic sea surface temperature are usually at their annual low” and the fluctuation over the year is large enough that it should counteract even a significant secular warming. Moreover:
“Because of its speed scientists are not yet linking this to the steady movements of climate change seen so far in the oceans. It might be natural variability, but whatever its explanation it is not replicated in most climate models.”
Perhaps because most climate models don’t replicate oceans well. Or measurement issues.
Our correspondent continues that if his assessment is correct it:
“might also explain why the waters of the North Atlantic seem to be warming fastest, because of the Gulf Stream off Canada and the Arctic we have warm water and very cold air, so back in the 70’s the thermometer bulb would cool very rapidly when taken out of the sea water bucket.”
If people really wanted to understand the situation, they’d make sure they used all the methods side by side in a sustained way so as to calibrate them against one another. Whereas if they wanted to hype a scary warming trend requiring them to get more money and power, they’d chuck that bucket over the side and pretend it had never been there.