Why Italy does not use cloud seeding to combat extreme temperatures

Heatwave Sweeps Across Southern Europe.

As temperatures continue to soar across Italy, the nation finds itself grappling with extreme heat conditions. Red alerts have been issued for 16 cities, including Rome, Florence, and Bologna, amidst predictions that Sicily and Sardinia could experience temperatures as high as 49C (120F) — a potential record for Europe. This heatwave, referred to as Cerberus, is largely due to a high-pressure area drawing hot air from Africa to Europe.

Related article: Italy: 200 Alpine glaciers gone since end 19th Century

Cloud Seeding: A Controversial Remedy

In the face of such scorching heat, the subject of cloud seeding — a weather modification method intended to induce rainfall — has emerged in global discourse. However, Italy’s government remains hesitant about this approach. The country’s reluctance stems from a deep understanding of the potential risks and limitations cloud seeding presents.

In Italy, an initial attempt at cloud seeding was carried out by Depietri in Modena in the 1960s, but it did not yield the anticipated results. To cope with a period of severe drought, cloud seeding experiments were conducted initially in the Puglia region from 1988 to 1994, as part of an operation known as ‘Progetto Pioggia‘, and subsequently in the Sicily, Sardinia, and Basilicata regions. These operations were jointly conducted by the Italian company Tecnagro and the Israeli firm EMS, a subsidiary of Mekorot Water Company, Ltd., with the aim of transferring Israeli expertise and technology to Italian soil. In the case of Puglia, the seeding technique used involved dispersing silver iodide from aircraft at the base of target clouds, at an approximate altitude of 800 meters. Regrettably, these experiments yielded subpar outcomes.

The People’s Republic of China hosts the world’s most extensive cloud seeding system, believed to enhance rainfall in several increasingly dry regions, including Beijing, by launching silver iodide rockets into the desired rain locations. Such interventions have even sparked political tensions, with neighboring regions accusing each other of ‘rain theft.’

China leveraged cloud seeding for a drier season during the 2008 Olympic Games in Beijing. In February 2009, amid a four-month drought, the country used iodide sticks over Beijing and other northern regions to artificially stimulate snowfall. This led to a three-day snowfall in Beijing, causing the closure of 12 main roads.

In late October 2009, Beijing experienced its earliest snowfall since 1987, attributed to cloud seeding. A 2021 research paper from Tsinghua University, published in the peer-reviewed journal Environment Science, revealed another instance of weather modification. On July 1, 2021, the Chinese Communist Party held its centenary celebration in Tiananmen Square. The study indicates that the government employed cloud seeding to induce rainfall the evening before the event, reducing PM2.5 pollution levels by over two-thirds and improving air quality from ‘moderate’ to ‘good’. However, the success of these attempts are contested.

Dissecting the Process and Concerns

Cloud seeding is a process that involves dispersing substances into the air, which then serve as a basis for cloud formation and subsequent precipitation. Despite its potential to provide relief in drought-stricken areas, the reality of cloud seeding is marred by several complications.

Firstly, its effectiveness is still a topic of scientific debate, with some studies suggesting successful results, while others showing inconclusive or minimal impact.

The effectiveness of cloud seeding in significantly enhancing precipitation remains a contentious topic among scholars, with varying results and opinions depending on the specific study or expert consulted.

A study by the National Academy of Sciences found no strong statistical evidence supporting the effectiveness of cloud seeding. Stanford University ecologist Rob Jackson, based on the study’s results, stated that while it might be possible to marginally increase snow or rain in certain places and under specific conditions, this is quite different from a program claiming to consistently augment precipitation.

In 2003, the US National Research Council (NRC) issued a report stating that, despite significant progress in understanding daily weather processes over the past 55 years, there was no scientifically acceptable proof for significant effects from seeding.

In contrast, Jeff Tilley, Director of Weather Modification at the Desert Research Institute in Reno, asserted in 2016 that advancements in technology and research have yielded reliable results, making cloud seeding a dependable and cost-effective water supply method for many regions. Furthermore, the American Meteorological Society suggested in 1998 that cloud seeding could seasonally increase precipitation from supercooled orographic clouds (clouds formed over mountains) by about 10%.

Secondly, the introduction of foreign substances into the environment via cloud seeding can have unforeseen ecological impacts. The potential consequences of such interventions remain largely unknown and could potentially be harmful.

Silver iodide, used in cloud seeding, has an NFPA 704 health hazard rating of 2, suggesting it could cause temporary incapacitation or possible residual injury to humans and other mammals under intense or sustained exposure. However, numerous comprehensive ecological studies have indicated minimal environmental and health impacts. The low toxicity of silver and silver compounds, such as silver iodide, likely results from the minor quantities used in cloud seeding, which constitute about one percent of global industrial emissions or individual exposure from dental fillings.

Observed accumulations in soil, vegetation, and surface runoff have not significantly exceeded natural levels. Environmental assessments conducted in the Sierra Nevada of California in 1995 and by an independent panel of experts in Australia in 2004 support these findings.

However, cloud seeding in sensitive areas like Kosciuszko National Park, a biosphere reserve in Australia, has raised concerns. Rapid changes in environmental legislation enabled trials, sparking worries about the impact of elemental silver uptake on sensitive species like the pygmy possum and the occurrence of algal blooms in glacial lakes.

Limited Scope and Ethical Implications

Cloud seeding is not a guaranteed solution for extreme heat. Its success depends on the existence of clouds, which may be rare or non-existent during a heatwave. Even if cloud seeding does lead to increased cloud cover, it may not result in a significant temperature drop in extreme heat situations.

Furthermore, cloud seeding raises ethical questions. The process involves weather manipulation, leading to discussions about the right to alter weather patterns and the potential effects of such interventions, especially in shared weather systems.

Italy’s Stand and the Underlying Urgency

In light of these considerations, Italy has opted for a cautious approach, abstaining from adopting cloud seeding. The country has instead focused on issuing warnings to its citizens and urging them to take precautions during peak sunlight hours.

Experts predict that such extreme weather events will become more common and intense, posing a significant risk to the European population. As Alvaro Silva from the World Meteorological Organisation suggests, half of Europe may face high or very high risk of heat stress by 2050.

Topics: Italy’s Decision on Cloud Seeding, Impact of Heatwave in Italy, Italy’s Approach to Weather Modification, Reasons for Italy’s Refusal of Cloud Seeding, Ethical Implications of Weather Manipulation, Environmental Impact of Cloud Seeding, Climate Change and Extreme Heat in Italy