It was the moral equivalent of a fart in a hurricane. The "hurricane" was the explosion of the Mount Pinatubo volcano in the Philippines in 1991, which boosted 17 million tonnes of sulphur dioxide into the stratosphere.
The sulphur dioxide didn't hurt anything because there are no living things in the stratosphere.
Moreover, it stayed up there long enough, reflecting some incoming sunlight, to lower the average global temperature by half a degree Celsius for about a year.
This was the time when "global warming" was first recognised as a serious threat to human welfare.
Scientists, aware of this phenomenon, speculated that putting sulphur dioxide into the stratosphere might serve as an "emergency brake" if the warming ever gets out of control. But there was no emergency, so they just filed the idea under "contingencies".
Fast forward three decades, and last week Luke Iseman, the co-founder and CEO of fly-by-night startup "Make Sunsets", revealed that he pumped a few grammes of sulphur dioxide into a weather balloon at a secret launch site in Mexico's Baja California.
He then freed the balloon to rise into the stratosphere, where it presumably ruptured and released the SO2.
That was the fart. A quite deliberate fart, intended to get everybody's attention. And Mr Iseman's company is already offering to sell US$10 (338 baht) "cooling credits" for releasing one gramme of sulphur dioxide particles in the stratosphere -- enough, he says, to offset the warming effect of one tonne of carbon dioxide for one year.
We are currently putting about 44 billion tonnes of carbon dioxide into the atmosphere each year, so counteracting one year's warming at the price Mr Iseman plans to charge would bring in $440 billion.
That's about one hundred times the amount that real scientists calculate it would cost to cancel one year's warming, so it gives him a decent profit margin.
Is this guy for real? Not entirely. He was previously a director of hardware at Y Combinator, so he is a player of sorts, and he will undoubtedly cash the cheques that people send him.
But about his company, "Make Sunsets", he says that "We joke/not joke that this is partly a company and partly a cult."
The balloon launches (there were actually two of them) were pure provocation without a scintilla of science. The payloads were so small as to be meaningless, there was no instrumentation to observe the "experiments" anyway, and Mr Iseman doesn't even know the altitude that the balloons actually burst at.
But he was looking for a reaction, and he got one. The scientists who are really investigating "climate engineering" techniques unanimously condemned his rogue behaviour.
Harvard University's David Keith blogged that "commercial development cannot produce the level of transparency and trust the world needs to make sensible decisions about deployment".
And of course, the many people who fear geoengineering and distrust even the real scientists who work in the field rejoiced at the gift Mr Iseman has given them. He's exactly the kind of reckless and egotistical monster that they imagine they are fighting, and he has given them years' worth of ammunition for anti-geoengineering propaganda.
Why is Mr Iseman really doing this? To save humanity, he probably tells himself. If you have been nurtured in the self-regarding Silicon Valley swamp for long enough, you can actually believe that the fate of the human race is in your hands -- and that there's no crime in turning a buck or two while you're saving it.
But his actions are doing real damage. We are probably going to need an emergency brake on the warming as soon as the mid-2030s, if the real-world consequences of breaching the "never-more-than +1.5 degrees Celsius" limit are as grave as they are starting to seem.
That means we have perhaps a dozen years to do all the research that will tell us how to safely deploy "stratospheric aerosol injection" of sulphur dioxide (or some alternative reflecting particle), and to develop the equipment that would actually do it.
It is a highly controversial topic, largely because there is a huge amount of disinformation about it and a lot of opposition that is really ideological rather than science-based. It's going to take a lot of time to reach a global consensus that holding the temperature down temporarily with geoengineering techniques is the least bad option.
If Mr Iseman can get enough attention, he could delay the consensus for a critical extra year or two. Am I helping him by writing this? I hope not.
