Concerned that rumours of his ‘nightly bedfellows’ were further destabilising his already turbulent reign, James VI of Scotland (and later James I of England) resolved in 1589 to take himself a wife. He chose Anne of Denmark and sent for her. She set sail in August but did not arrive in Leith, Edinburgh’s port. On investigation it transpired that a great storm had forced her to turn back. In order to collect her from Denmark, James crossed the North Sea in autumn and ended up staying until the spring. Despite the weather having been set fair, when he and his new bride headed back home, the royal fleet was hit with more violent storms, and one of the ships was lost.

The Danes were quick to point the finger at witches; James did, too. The first woman to confess was Geillis Duncan, a young maidservant from East Lothian, who said she had been part of an extensive network of witches who had plotted the death of the king and his new bride. Another, Agnes Sampson, was personally interrogated by James at Holyrood House in Edinburgh. She told James the plot had been masterminded by Francis Stewart, Earl of Bothwell, who had a serious claim to the throne, since his father had been the illegitimate son of James V. At the trial of the ‘North Berwick witches’, Sampson testified that the devil hated the king. The possibility that James’ travails in his kingdom were caused not by miscalculation and misfortune but witchcraft led him to think of himself as the upholder of the Christian faith, on a divine mission to rid his country of Satan’s influence. He presided over a series of harsh witch-hunts, was the only monarch to author a treatise on witchcraft (his Daemonologie), and on becoming king of England in 1603 saw that the English Act Against Witchcraft of 1604 was considerably beefed up.

We accept that the weather can have serious geopolitical consequences. There are two questions that matter: who directs it, and whose fault is it? If we park for a moment the question of direction, then the issue of blame becomes one of failure to forecast or to prepare. Rain, wind, heat and cold cause floods, famines, disease, and all in turn affect local, national and international politics, depending on how they are dealt with and whether they are exploited. If the weather creates inconvenient facts (poor harvests, inundated villages), the response is up to us. We can warn, build and maintain defences, evacuate, repair, help. Or – if we do some of them imperfectly – there will be misery, blame and revolt.

In fulfilling its vision to be ‘America’s calm, clear, and trusted voice in the eye of the storm’, the US National Hurricane Center tracks tropical storms as soon as they start to form in the waters around West Africa and refines its estimation of the precise course constantly. Its mission is ‘to save lives, mitigate property loss, and improve economic efficiency by issuing the best watches, warnings, forecasts, and analyses of hazardous tropical weather and by increasing understanding of these hazards’. As with every national meteorological organisation, as new technology enhances prediction capabilities, the challenge remains getting the balance right between over-warning and under-warning, and building the right relationships between the forecasters, those responsible for preparation, and the public when they need to act. The theory is straightforward: it is impossible to change the weather, but those who know what is coming can change the outcome. If that response is considered a failure then there will be political repercussions.

The World Meteorological Organisation (WMO) is the United Nations’ authoritative voice on the behaviour of the earth’s atmosphere. Based in Geneva, it provides a framework for international co-operation among the 193 member states, since weather, climate and the water cycle know no national boundaries. It facilitates real time data exchange and sets standards, and its vision is that by 2030 ‘all nations, especially the most vulnerable, are more resilient to the socioeconomic consequences of extreme weather, climate, water and other environmental events’. The UK Met Office is a Global Producing Centre of long-range forecasts for the WMO. The leitmotif is security: food security, climate security, national security. It is expected that climate change will create greater competition for resources and greater instability, which threatens food availability and affordability, economic stability, public health, and the chaos caused by demographic shifts. Global long-range probabilistic forecasts for temperature and rainfall are used to suggest areas of political instability (although this is far from a perfect science).

Weather-watching and forecasting developed to track and predict how the atmosphere would behave, based on the contemporaneous assumption that it was impossible for humans to change the weather, but it was possible to understand it and to take action to prevent its impact. In the time of James VI/I the conclusion was quite the reverse: bad weather events had to be the deed of a more powerful actor, but who had been doing the summoning or incanting mattered. There were conclusions to be drawn if the fates threw a squall. It was hardly a coincidence that Macbeth was published shortly after James became king of England, depicting the acts of the witches as not just devilry, but a conspiracy against the state. When the three witches in Act 1 Scene 3 discuss the raising of winds at sea, this was seen as directly relating to the king: ‘Though his bark cannot be lost, Yet it shall be tempest-tossed.’

So to the question of direction in the modern age. Scientific developments mean that it is now possible for a nation, a politician or a billionaire to change the weather, and this fact complicates things. From 1967 to 1972 the 54th Weather Reconnaissance Squadron of the US Air Force conducted ‘Operation Popeye’ in Vietnam, using cloud seeding to seek to extend the monsoon season and so flood the Ho Chi Minh Trail. This programme of using weather modification as a tactical weapon prompted a response: in 1976 the United Nations passed the ‘Convention on the Prohibition of Military or any other Hostile Use of Environmental Modification Techniques’ (ENMOD), prohibiting states from engaging in military or other hostile use of environmental modification techniques that might have widespread, long-lasting or severe effects as the means of destruction, damage or injury to another state party. ENMOD was ratified by 78 signatories, including the Soviet Union and the US but not China. The concept of the ‘weather as a weapon’ had arrived, and the highly classified nature of some of these operations generated a climate for conspiracy theories.

Cloud seeding is the spraying – either from aircraft or from ground-based generators – of substances such as cement powder, dry ice or silver iodide particles into the clouds to stimulate the formation of ice crystals, which improves the cloud’s ability to form rain or snow. Since the technology exists, in the face of global warming those countries most affected or most able are succumbing to the natural temptation to use weather modification techniques for benign purposes. The World Meteorological Organisation can’t avoid the fact that an increasing number of states and people are tempted to the positive sides of ‘rain enhancement’, which mitigates climate change impacts. In the margins of COP 28 in Dubai in December 2023 the UAE National Center of Meteorology hosted an event exploring the positive aspects of a programme to increase or optimise rainfall and manage water resources. For states such as the UAE, which are due to become unliveable because of the effects of climate change, the possibility of creating rain to mitigate the impact of prolonged droughts and recharge aquifers is a significant one and may be of existential importance.

Cloud seeding is now being used all over the world as a method for enhancing winter snowfall and increasing natural water supply. According to the Nevada-based Desert Research Institute (DRI), long-term cloud seeding projects over the mountains of Nevada and other parts of the world have been shown to increase the overall snowpack in the targeted areas by 10 per cent or more per year. At a study site in the Snowy Mountains of New South Wales, Australia, a five-year cloud-seeding project designed by DRI resulted in a 14 per cent increase in snowfall across the project area. In Wyoming, a 10-year cloud-seeding experiment in the Snowy and Sierra Madre ranges resulted in five to 15 per cent increases in snow pack from winter storms.

Moscow Mayor Yuri Luzhkov (1992-2010) embraced early on the opportunities a promise to improve the weather might offer to a political campaign. He used the Russian air force to spray the clouds, preventing rainfall on Victory Day in May and City Day in September. In 2009 he escalated his war on weather with plans to slash snowfall by one fifth in the city, using the Russian air force and air defence systems to intercept and inject storm fronts. The catch would be that the snow would have to fall somewhere.

Which brings us back to the geopolitics, where perceptions of threat and consequences matter almost as much as reality, particularly with a proliferating and not fully understood capability. In January 2024 the Indian Defence Minister Rajnath Singh said that climate change in India was not just a weather-related phenomenon but was about national security, noting an increase in the number of natural disasters in the states bordering Tibet, the areas where the Line of Actual Control between India and China is disputed.

China is serious about weather modification; Mao Zedong championed the idea as far back as 1956, and the first experiments were conducted in northern and western China in 1958. It passed its first Weather Modification Law in 2002 for the purpose of strengthening the administration of weather modification, added weather to its Five Year Plans in 2005, and has invested close to $2 billion in weather modification since 2014, with activities covering one third of China’s total land area (between 2014 and 2020 this caused an estimated 79.2 billion tons of annual increase in rainfall and snowfall). It has changed the weather for major events, such as the 2008 Beijing Olympics and the 2022 Winter Olympics, and created rain to reduce pollution for the centenary celebration of the Chinese Communist Party in 2021. Under the 2021-25 Weather Modification Development Plan (WMDP), the area covered is expected to be 5.5 million square kilometres for rainfall/snowfall enhancement, and 580,000 for hail suppression, an area 150 per cent larger than that of India. The new WMDP also encourages the automation of weather modification delivery methods, especially the use of unmanned aerial vehicles (drones) and artificial intelligence.

So humans are changing the weather, in local and state-sponsored initiatives. The fact that these are localised, and may be attached to state programmes that are sensitive, makes it difficult to understand what kind of weather is being changed where and by whom. Even benign programmes will have consequences. Which in turn creates difficulties: when it is claimed on the internet that shadowy forces in thrall to the US government created Hurricane Milton, one of the strongest storms in US history, the problem is that it requires refutation. It is possible for conspiracists to believe in the theory because authoritarian governments do mess with the weather. Cloud seeding is used to shift or cause rain.

James VI commissioned a pamphlet, ‘Newes from Scotland’ to report on the North Berwick witch trials, published in 1591. It contains a detailed account of how the witches caused the storm: ‘Moreover she confessed that at the time when his Majesty was in Denmark, she being accompanied with the parties before specially named, took a Cat and christened it, and afterward bound to each part of that Cat, the cheefest parts of a dead man, and several joints of his body, and that in the night following the said Cat was conveyed into the midst of the sea by all these witches sailing in their riddles or Cues as aforesaid, and so left the said Cat right before the town of Leith in Scotland: This done, there did arise such a tempest in the Sea, as a greater has not been seen, which tempest was the cause of the perishing of a Boat or vessel coming over from the town of Brunt Island to the town of Leith, of which was many Jewels and rich gifts, which should have been presented to the current Queen of Scotland, at her Majesty’s coming to Leith.’

It is unlikely that today’s extreme weather events are caused by witchcraft, although climate change is of course blamed on the effects of polluting human behaviour. But as the question of bad weather becomes truly existential for an increasing number of states or their governments, and techniques for modifying, managing and enhancing our weather develop, we should expect to see an increase in experiments to change it. Multilateral bodies such as the WMO will have a critical role in ensuring a degree of sharing, transparency and standardisation as humans alter the behaviour of the atmosphere, not least to address ethical questions and concerns about unintended consequences, but most importantly to ward off suspicion and theory about the causes.