Episode Overview

Podcast: Unexplainable by Vox
Episode: Cloud atlas
Date: February 2, 2026

This episode dives deep into the mysteries of clouds—how they form, why they're so hard to predict, and their profound influences on weather and climate change. Through personal stories, expert interviews, and a touch of art and history, the "Unexplainable" team explores the knowns and vast unknowns about the clouds above us. The episode balances scientific insight with poetic appreciation, ultimately highlighting just how much we still have to learn about the sky we live in.

Key Discussion Points & Insights

1. Experiencing Clouds Up Close

[01:31-04:15] Tom Warner's Story: Flying Into Thunderstorms

• Tom Warner, a pilot, recounts flying a vintage WWII-era plane directly into massive cumulonimbus clouds, describing their immense power and beauty.

• The visceral experience includes intense updrafts, hail, noise, St. Elmo's fire (charged plasma visible on the plane), and the sense of flying "inside a thunderstorm."

  "We would aim right for it... as soon as you hit that wall, the aircraft would start to rise on its own. We could be climbing at 2,000ft per minute... Lots of rain and hail. And that was one thing that was just remarkable to me was just how noisy it was, how loud the hail was."
  — Tom Warner (01:52)

• Despite the danger, the mission is scientific: understanding clouds from the inside out.

2. Why Clouds Matter—and Are Still Unexplained

[04:31-06:18] Cloud Scientists’ Fascination & Importance

• Cloud lovers: Multiple scientists express their passion for clouds—both for their aesthetic appeal and scientific richness.

• Critical for daily life: Clouds mediate weather, rainfall, temperature, and thus food production, water cycles, and even our ability to cope with climate change.

  "Clouds are where the rubber meets the road in terms of weather... A lot of the things that we do day to day, are affected by clouds in really profound ways."
  — Umair Irfan (05:44)

3. What is a Cloud?

[06:28-09:31] Breaking Down the Basics

• Fundamental building blocks: Clouds form when water vapor condenses onto aerosols—tiny particles such as dust, pollen, salt, pollution, or even intentionally seeded chemicals.

• Surprisingly heavy: A typical 1km³ cloud can contain about a million pounds of water—more than many ponds or even rivers—hovering weightlessly above us.

  “If you look up at a cloud, they look almost weightless... That's about a million pounds of water right there... ponds and lakes worth of water directly above your head."
  — Umair Irfan (08:22)

• Why don’t they fall? Cloud droplets are so tiny that, like fine mist from a spray bottle, they stay suspended in air—sometimes for long periods.

4. The Complexity of Cloud Formation & Prediction

[10:17-13:41] Emergent Phenomena and the Limits of Prediction

• From droplets to chaos: Modelling individual droplets is already tough; aggregating billions leads to unpredictable, chaotic systems, akin to a "double pendulum" that quickly becomes impossible to predict.

• The boundaries of a cloud: Not as clear-cut as they seem—clouds blend and churn with the surrounding air, making their edges (and even their definition) fuzzy.

  "When you have a really small effect, it grows... The atmosphere is chaotic. And when you make one tiny change, that can grow exponentially and change everything."
  — Angie Pendergrass (11:15)

• Emergence: Individual water droplets behave predictably but, en masse, clouds take on "emergent" behaviors that can’t be extrapolated from their parts.

5. Clouds & Climate: Double-Edged Sword

[17:01-19:59] Clouds in the Climate System

• Biggest uncertainty: In climate models, after unpredictability in human behavior, clouds are the largest unknown.

  "Clouds are almost always the largest source of uncertainty in those [climate] models."
  — Umair Irfan (17:24)

• Cooling vs. warming:

  • Low, fluffy clouds reflect solar radiation, helping cool the Earth—“like wearing white on a hot day.”
  • High, icy, translucent clouds let sunlight in but trap infrared heat—acting "more like a blanket."
  • The future mix of these clouds is unknown.

  "Low clouds... do a really good job of reflecting that incoming solar radiation back out into space... [High] clouds...are very effective at blocking the outgoing infrared radiation, so they act more like a blanket."
  — Scott Collis ([17:45]/18:24)

• No "before picture": We lack a good historical record of cloud types and coverage before human industrial activity, making predictions especially hard.

6. Searching for Clues in History, Art, and Culture

[20:35-24:41] Digging Into Records & Representations

• Ship’s logs: Scientists mine centuries-old maritime logs to reconstruct “pre-industrial cloudiness.”

• Art & literature: Clouds depicted in ancient stone carvings, Romantic landscape paintings, and even in Edvard Munch’s "The Scream" offer clues, although artistic license makes quantification tough.

  "You can see carvings on stones in Mexico showing cumulonimbus storm clouds with recognizable features to them, you know, thousands of years old."
  — Brian Resnick (22:14)

  "Paintings and Art— they're constructed a lot of the time. ...They don't give you a real indication of how many of them there were, how often they were around."
  — Brian Resnick (24:15)

7. Embracing Uncertainty and Wonder

[25:21-end] Where We Stand & the Power of Clouds

• Humility and motivation: Our lack of knowledge should ground us and drive continued research.

  "I think it should leave us here with a little bit of humility... But it should also give us, you know, inspiration and motivation to study this further."
  — Umair Irfan (25:39)

• Connectedness: We do not live beneath the sky—we live within it. What happens in the atmosphere is not separate from us; we are participants as well as observers.

  "We don't live beneath the sky, we live within it. And the sky is an ocean that we inhabit. We just happen to live on the bed of that ocean."
  — Brian Resnick (26:07)

• Pause and appreciate: Amid ongoing research and uncertainty, appreciating the transient beauty and mystery of clouds can help “keep your feet on the ground.”

  "To have a few moments with your head in the clouds helps you keep your feet on the ground."
  — Brian Resnick (26:56)

Notable Quotes & Memorable Moments

• "It was about getting the opportunity to witness the power, the beauty, the strength of severe weather from inside a thunderstorm. And not many people have had that opportunity."
  — Tom Warner (02:19)

• "If you were to imagine, say, a cloud that's, you know, a kilometer on each side... that's about a million pounds of water right there."
  — Umair Irfan (08:22)

• "The atmosphere is chaotic. And when you make one tiny change, that can grow exponentially and change everything."
  — Angie Pendergrass (11:34)

• "Clouds are almost always the largest source of uncertainty in those [climate] models."
  — Umair Irfan (17:24)

• "We don't have a good sense of what clouds were like before a human started drastically interfering in the atmosphere. ...clouds themselves, they have barely a footprint. ...there's no fossil record."
  — Umair Irfan (18:58)

• "We don't live beneath the sky, we live within it. And the sky is an ocean that we inhabit."
  — Brian Resnick (26:07)

• "To have a few moments with your head in the clouds helps you keep your feet on the ground."
  — Brian Resnick (26:56)

Timestamps for Important Segments

• [01:31] Tom Warner describes flying into thunderstorms
• [04:31] Introduction of why clouds are studied and their importance
• [06:28] What exactly is a cloud?
• [10:17] The unpredictability and emergent complexity of clouds
• [17:01] The role of clouds in climate change uncertainty
• [20:35] Using historical records, art, and literature to reconstruct cloud history
• [25:21] The need for humility and ongoing research into clouds
• [26:07] A poetic reflection on living "within" the sky

Final Thoughts

This episode paints clouds as both everyday and fundamentally elusive—crucial drivers of weather and climate, yet deeply complex and still, in many respects, unexplainable. The science is filled with awe, humility, and a sense of wonder, encouraging listeners to stop, look up, and remember just how mysterious the world above us remains.