The Irish Scientist Who Discovered Why We Need Solar Panels Today

Part 5 of our Irish Renewable Energy Pioneers series

In 1859, an Irish physicist from County Carlow proved something that would change the world forever. John Tyndall discovered that carbon dioxide traps heat in the atmosphere. He had no idea that 167 years later, his work would explain why over 200,000 Irish homes are now racing to install solar panels.

Tyndall didn't set out to predict climate change. He just wanted to understand why the Earth stays warm at night.

The Ham Sandwich Mountaineer Who Changed Climate Science

John Tyndall was born on 2 August 1820 in Leighlinbridge, a small village in County Carlow. He worked as a surveyor and civil engineer before studying physics in Germany. By his 30s, he had become one of Britain's leading experimental scientists at the Royal Institution in London.

But Tyndall wasn't your typical Victorian lab coat. He was an obsessive mountaineer who once climbed Monte Rosa in the Swiss Alps solo, armed with nothing but a ham sandwich and a thermometer. He wanted to measure air temperature at altitude. That's the kind of scientist he was: part researcher, part adventurer, 100% committed to answering the question "but why?"

In 1859, Tyndall turned his attention to a puzzle that had stumped scientists for decades. Why doesn't the Earth freeze solid at night when the sun goes down? The answer, he suspected, lay in the atmosphere.

The Experiment That Explained Everything

Tyndall built a four-foot-long brass tube and filled it with different gases. He shone infrared radiation (heat) through the tube and measured how much energy came out the other side using a device called a thermopile.

Nitrogen and oxygen, the two gases that make up 99% of our atmosphere, let heat pass straight through. No absorption. No warming effect.

Then he tested carbon dioxide.

The heat vanished. CO₂ absorbed infrared radiation like a sponge. Water vapour did the same. So did methane and ozone. These gases, Tyndall realised, act like a blanket around the Earth. They let sunlight in but trap the heat trying to escape back into space.

He had discovered the greenhouse effect.

Tyndall wrote: "This aqueous vapour is a blanket more necessary to the vegetable life of England than clothing is to man."

He understood that without these trace gases, Earth would be a frozen wasteland. But he also noted that changes in atmospheric composition could dramatically alter the planet's temperature. In 1861, he speculated that past ice ages might have been caused by lower levels of CO₂.

He was right.

The Tyndall Effect and Other Party Tricks

Tyndall didn't stop at climate science. In 1869, he discovered why the sky is blue. When he shone light through a tube filled with fine particles, he noticed that blue light scattered more than red light. This became known as the Tyndall effect, and it explains everything from blue skies to why milk looks white.

He also:

• Coined the term "calorescence" to describe infrared light converting to visible light (1864)
• Invented the first capnograph to measure CO₂ in exhaled breath (1864)
• Improved the design of firefighters' respirators (1871)
• Created the "Tyndall bar-breaker," a device to demonstrate molecular forces (1867)
• Discovered thermophoresis, the movement of particles in a temperature gradient (1870)

In his spare time, he gave wildly popular public lectures and climbed mountains. He died in 1893 from an accidental overdose of chloral hydrate, a sedative his wife mistakenly gave him.

From Victorian Labs to Irish Rooftops

So what does a 19th-century physicist have to do with the solar panels going up on Irish roofs today?

Everything.

Tyndall's discovery of the greenhouse effect is the reason we know that burning fossil fuels warms the planet. CO₂ levels have risen from 280 parts per million in Tyndall's time to over 420 ppm today. Every coal plant, petrol car and gas boiler adds more of that invisible blanket to the atmosphere.

Solar panels, batteries and electric vehicles are the direct response to Tyndall's warning. They allow us to generate, store and use energy without pumping more CO₂ into the air.

In 2026, Ireland surpassed 3 GW of installed solar capacity. Renewable electricity now provides nearly half of the country's power. Solar panels on Irish roofs are generating over 1 GW at peak times, enough to power half a million homes. Every kilowatt-hour they produce is a kilowatt-hour that doesn't come from burning fossil fuels.

Tyndall would have loved it. A man who once hauled scientific equipment up an Alpine peak to measure temperature would absolutely appreciate the elegance of turning sunlight directly into electricity on your roof.

Final Thoughts

John Tyndall discovered the greenhouse effect in a London lab in 1859, but his legacy is written across every solar panel, home battery and EV charger installed in Ireland today. He gave us the science. We're finally building the solution.

Coming Next: Part 6: Meet the UL Scientist Building Ireland's Next-Generation Batteries 

Ready to Be Part of Ireland's Renewable Energy Story?

The science is settled. The technology is ready. And the grants are still live. If you're thinking about solar panels, battery storage or an EV charger for your home, WattCharger can help you make it happen.

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