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How Climate Change /Actually/ Works...in 4 Minutes

2022-07-29 · explainer · Hank · 3:56 · watch on YouTube

Topic: Science & nature · mode: Explainer

Hank explains climate change without the greenhouse metaphor: more energy now enters Earth's atmosphere than leaves; carbon dioxide and methane are clear in visible light but black at infrared wavelengths, so they absorb photons and heat the air, driving heat, severe weather and change our infrastructure was not built for.

What is said

The parts of the video and what is said in each (★ — how much it matters to the video).

00:00:00 — Energy imbalance and its three effects: more heat, more severe weather, and change that infrastructure was not built for

  • ★★★ Hank says that for a long time the energy entering and leaving Earth's atmosphere was about equal, which kept temperatures steady, but now more energy is coming in than going out. — 00:00:00 · Earth
  • ★★★ Hank says the energy imbalance causes three things: more heat (molecules moving faster), more severe weather (many molecules moving together), and, probably worst, things being different. (hedged) — 00:00:00
  • ★★★ Hank says human infrastructure assumes rainfall and temperature stay as they were; as they change, crop yields might fall and leave people hungry, power grids fail under air conditioning, and forests burn. (hedged) — 00:00:46

00:01:15 — How light is absorbed, reflected or passed, and how molecules heat up: radiation, conduction and convection

  • ★★ Hank explains why a black t-shirt gets hotter than a white one: black things absorb all visible light hitting them, while a white shirt reflects it. — 00:01:15
  • ★★ Hank says a material can only absorb, reflect or let light pass through; absorbed light becomes movement in the molecule, which passes to other molecules like a cue ball hitting a pool ball. — 00:01:15
  • ★★ Hank says molecules heat up in two ways: absorbing a photon (radiation) or being hit by a faster-jiggling particle, called conduction in solids and convection in fluids. — 00:01:45
  • ★★ Hank says that in the shade 99% of the heat you feel comes from convection, while in the sun it is a mix of radiation and convection, which is why the sun feels hotter. — 00:01:45

00:02:43 — Carbon dioxide and methane are black at infrared wavelengths; how this drives weather, wildfires and storms; why the fix is hard but the problem understood

  • ★★★ Hank says carbon dioxide and methane absorb no visible light, so they are clear, but they are black at certain infrared wavelengths the sun produces a lot of; adding them makes the atmosphere less clear there. — 00:02:43
  • ★★ Hank says these molecules absorb photons and speed up, knocking into others until the hot air rises and cooler, denser air rushes in: that is weather. — 00:02:43
  • ★★ Hank says the hotter air might draw more moisture from the soil, causing more wildfires, and evaporate more ocean water, causing bigger storms. (hedged) — 00:03:12
  • ★★★ Hank says we know that, how and why this happens and what its effects are, and that the only way to stop it is less CO2 and methane in the atmosphere. — 00:03:12
  • ★★ Hank says cutting these gases is very hard: removing them from the atmosphere is hard and expensive, and so is replacing the agriculture, energy and transportation infrastructure that releases them. — 00:03:12
  • ★★★ Hank says the problem is not easy to solve but well understood, and he thinks people can solve basically any problem if only they agree it exists. — 00:03:41

In the description and comments

  • ★ The description says Hank agrees with simplifying climate change as a greenhouse or heat-trapping blanket, but the real story is simple: more energy comes in than goes out because of 'wiggles'. (playful) — video description · climate change
  • ★★ The description says Hank made the video because it feels like the US may finally pass a climate bill that measurably reduces emissions on a fairly tight time scale, which would be massive. (hedged) — video description · United States
  • ★★ In a comment, Hank says he left out the ground's absorbing and re-emitting light, though among the most important mechanisms of climate change, because people don't think of Earth emitting light and it would confuse. — creator comment · climate change, Earth
  • ★ In a comment, Hank says methane capture isn't really an option but isn't needed, since methane removes itself, while carbon capture is expensive but getting cheaper. — creator comment

Threads in this video

Where the stories that moved here went next

Mentioned

Central: carbon dioxide · Infrared · methane

Also: Convection · crop yield · Earth · photon · Thermal conduction · Thermal radiation · wildfire

Only in the description or credits: climate change · United States

Also centred on carbon dioxide: The Biggest Climate Bill of Your Life - But What does it DO!? · October 4, 2024

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