Liz Bentley, Chief Executive of the Royal Meteorological society, explains the science of weather prediction. Mark Miodownik discusses the technique of cloud seeding for inducing rainfall, but highlights its unreliable results. The podcast explores the challenges of verifying the effectiveness of cloud seeding and delves into the political implications of manipulating the weather. Additionally, it examines desertification and advancements in desalination technology. Nature versus nurture is also contemplated.
Cloud seeding has limited efficacy and faces challenges in accurately predicting weather patterns and their long-term effects on the ecosystem.
Weather forecasts have become more accurate over time, but the exact effects of contrails on weather systems and global climate change still require further research.
Deep dives
Clouds and Rain
Clouds are formed when water in the atmosphere condenses around particles such as smoke or dust. Clouds do not always lead to rain, as rain formation requires specific conditions, including temperature changes and the presence of a sufficient number of water droplets. Cloud seeding is a process where artificial particles, like silver iodide, are introduced into the air to stimulate cloud formation. However, the effectiveness of cloud seeding in producing rain is hard to determine due to the difficulty of measuring its impact on naturally occurring rain. Cloud seeding has limited efficacy and has only been found to have a potential effect of around 3%. Geoengineering methods like cloud seeding, while showing promise for inducing rain, still face challenges in accurately predicting weather patterns and their long-term effects on the ecosystem.
Weather Forecasting and Contrails
Weather forecasts are generated by collecting large amounts of observational data from various sources, such as land-based measurements, satellites, and weather balloons. This data is then used in numerical models to simulate and predict atmospheric conditions. Weather forecasts have become more accurate over time, with improvements in computer power and modeling techniques, allowing for predictions up to a week ahead. However, forecasting remains a complex task due to the inherent uncertainty and variability of weather patterns. Contrails, which are the trails left by aircraft in the sky, can affect weather conditions. The absence of contrails during periods of low air traffic provides a unique opportunity to study their impact on climate and temperature fluctuations. However, more research is needed to better understand the exact effects of contrails on weather systems and global climate change.
The Limitations of Geoengineering and Desertification
While the concept of geoengineering, including cloud seeding, offers potential solutions to combat climate change, there are significant limitations and challenges. In the case of cloud seeding, the success of inducing rain depends on the availability of water vapor in the atmosphere. Drought-stricken areas with low humidity may not have enough water to generate rain even with cloud seeding. Additionally, the issue of scale arises, as artificially seeding clouds only has a minimal impact compared to the vast amounts of water involved in weather systems. Desertification, the process of land turning into desert due to climate change, presents a significant challenge for crop cultivation. While efforts have been made to genetically engineer crops that can thrive in arid environments, the success and feasibility of such methods still require further research and development. Furthermore, ethical considerations, the complexity of weather systems, and the unpredictability of human interventions make the effectiveness and long-term consequences of geoengineering uncertain.
The Interaction of Nature and Nurture
The 'nature versus nurture' dichotomy has evolved into the concept of 'nature via nurture.' Nature refers to genetic factors and inheritance, while nurture refers to environmental influences. These two factors are not in conflict but rather work together to shape individual characteristics and behaviors. Genetics provide a foundation, but the environment, experiences, and external factors also play a significant role in shaping an individual. The study of epigenetics has emerged to explore the complex interaction between genes and the environment. Epigenetic factors can affect gene expression, demonstrating the intertwined nature of genetics and environmental influences. Understanding this interaction contributes to our knowledge of how individuals develop and highlights the importance of both nature and nurture in shaping human traits and behaviors.
"Could you make a machine to make it rain in minutes?" asks listener Alexander from Hampshire, aged 12. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. Rutherford and Fry dive into the clouded story of weather modification.
First, we need to decide where and when we might deploy any rain machine. Liz Bentley, Chief Executive of the Royal Meteorological society, takes us through the science, maths and art of predicting the weather. Hannah heads down to the BBC Weather Centre to meet meteorologist Helen Willetts, who takes us through the highs and lows of forecasting.
And then for the technology itself. Mark Miodownik, scientist and author of Liquid: The Delightful and Dangerous Substances The Flow Through Our Lives, reveals that a technique called cloud seeding has almost certainly been tried in different places around the world for decades. But, whilst it’s supposed to induce showers and even clear the way for sunny spells, the results aren’t always reliable. And even if we can make it rain, Liz explains why messing with the weather may be at our peril.
Presenters: Hannah Fry, Adam Rutherford
Producer: Jen Whyntie
First broadcast on BBC Radio 4 in 2020.
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