Should We Be Worried About Contrails?

Geoengineering in the form of modifying weather happens. It can save decimation of farmer livelihoods by mitigating droughts, and it can risk the global food supply by reducing crop growth. Like nuclear fission, it’s useful in the hands of sane people working with the knowledge and assent of the wider community, or it has the potential to destroy much of what humankind has built if left in the hands of psychopaths. If we can approach it in a calm and rational manner, we may yet stop the psychopaths.

During the Second World War, bomber crews were said to hate the contrails their planes produced, providing white fingers across the sky that pointed enemy fighters directly to them. These have seemingly exploded across our skies as commercial air travel has multiplied, but like boiling frogs, surprisingly few really noticed until others pointed out the heat. Living in Geneva, Switzerland during the week-long grounding of aircraft due to the eruption of the Eyjafjallajökull volcano in Iceland in 2010, we had clear spring skies for the first time. Not a trail, not a wisp of residual cloud. Normal, it turned out, was not natural.

Condensation trails, or contrails, are clouds formed from condensation and from the water and particles that are emitted from aircraft engine exhausts. Fine particles released in the right conditions form a nidus on which droplets can form in humid, cold air. Jet engines also emit water as a combustion product. The very low pressure on the upper wing surface, the reason airplanes stay up in the air, also allows water vapor to precipitate. This is well documented, almost as old as high-flying aircraft, and annoying when you want to photograph a good sunset in much of Europe or North America.

Contrails can contribute to cirrus cloud formation, while aircraft changing altitude can also create some really otherworldly holes in cloud layers, such as on airport approaches. Clouds come and go naturally, from the ground to the upper atmosphere, if the conditions are right. Aircraft just help the process. And as clouds have sharp edges (when viewed from a distance), contrails can seem to turn on and off for the same reason (temperature and humidity at various altitudes).

There is a school of thought that streaks across the sky, or most of them, only began to appear recently and are the result of nefarious intent – geoengineering. The theory is that a whole hidden industry exists to make chemicals, transport them to airports, install them on commercial (i.e., passenger) aircraft or place in fuel, and then release at certain times or in certain regions. This, performed at scale, would require thousands of willing people, who all remain silent on the issue. This is possible, but people talk, including pilots, fuellers, manufacturing workers, truck drivers and airport security guards, and is a little hard to imagine at scale. Part of an air force may follow some stupid government agenda, and perhaps does. But that is a tiny minority of flights.

However, airborne geoengineering does happen. It has for nearly a century, particularly with intent to provide rain during droughts or more routinely in arid inhabited regions. In Australia and the United States, for instance, government agencies have for many decades sprayed compounds such as silver iodide from an aircraft to precipitate water vapour and cause rain during droughts. The hope is to save cattle farmers from ruin or augment a city’s failing water supply. These are not bad things, while mass cattle death and bankruptcy often are.

Geoengineering can also be unbelievably stupid. The British Government is planning to fund high altitude geoengineering to block sunlight. This is a pet project of some very rich people who consider themselves geniuses and is a real thing – I have directly heard the discussions on similar projects from people who can pay for them. It is based on the interesting conviction that while all previous episodes of global warming were due to some natural phenomena, the current one is solely due to the work of man, and that somehow dimming sunlight by setting up a reflective layer in the upper atmosphere is therefore a good thing (not interfering with nature but saving it, supposedly).

There is irony here. We now have nine billion people on Earth, and have defied all previous predictions of Malthusian catastrophe and starvation partly because vegetation (i.e., our crops) grow faster and use water more efficiently than they did 50 or 100 years ago. One reason for this is higher atmospheric carbon dioxide (CO₂). Plants need mainly CO₂, sunlight and water to grow. Whether CO₂ is the main cause of post-industrial global warming is irrelevant here. It likely plays a role, but anthropogenic emissions do not explain past warming periods. CO₂ has doubled from previously very low levels but it was much lower in the Middle Ages when the Norse grew crops in Greenland.

So, whether or not sun-blocking will reduce global temperatures, it will certainly reduce sunlight and plant growth. This will reduce harvests, both in yield and in some places in frequency. Mass starvation will be much more likely – all apparently for the greater good. It may even be better for investors in failing fake meat companies and other factory foods, which may explain some interest in sun-dimming – a clever commercial approach but likely to be fairly widely fatal. While the British Government is embracing this, it is almost certainly happening already at least experimentally. There are no rules, just stupidity.

For those who support geoengineering, especially of the particularly stupid sun-dimming type, sidelining opposition by letting them appear foolish and readily ‘debunked’ is a good tactic. Claims that every contrail and unusual cloud formation suggests nefarious intent will help the cause. Clouds do come in the weirdest shapes and even colours. Nature is amazing, even if psychopathic rich people who wish to control it are not.

We should stop idiots from promoting sun-blocking and putting the global population’s food security at risk. We should consider carefully the cloud seeding that keeps many farmers in business, quite a different issue where intervention is very short-term and local. We should stop flying if we really want to eliminate contrails (they can be as ugly as windfarms) and want to reduce high altitude cirrus on summer days. But most people I know want to keep flying, and most farmers don’t want to go bankrupt or bury their cattle. 

So, perhaps we should concentrate on the industrial and political stupidity that is endangering us all through stuff that is proven and readily demonstrable. Labelling nature or air travel as evidence of evil will gain likes on social media, but also help the cause of those who would own and control our atmosphere and food supply.

There is a real problem and major threat out there that we should deal with, if only we can focus.

Dr David Bell is a clinical and public health physician with a PhD in population health and background in internal medicine, modelling and epidemiology of infectious disease. Previously, he was programme head for malaria and acute febrile disease at FIND in Geneva and coordinating malaria diagnostics strategy with the World Health Organisation. He is a Senior Scholar at the Brownstone Institute.