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The Living Archive · The Climate Translation

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Imagine walking through a quiet muddy wetland.
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Your boots sink into the soft ground.
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The air is cool and damp.
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Nothing about the landscape seems particularly remarkable.
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It's just moss, water, and mud.
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But what if I told you that every step you took was carrying you across thousands of
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years of Earth's history?
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Some peatbogs have been accumulating since before the Egyptian pyramids were constructed,
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and as scientists have learned more about these remarkable ecosystems, they've realized
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they're preserving something else as well, enormous amounts of carbon.
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Today we're exploring the living archive, in what scientists are doing to protect
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Earth's slowest growing ecosystems and the planet's most remarkable natural archive.
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Welcome back to the podcast, I'm Dr. Mac, and this is the Climate Translation.
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Last autumn, millions of leaves fell from trees across North America, and they covered sidewalks
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and filled gutters, blanketed yards.
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Many of us probably spent weekends raking them into piles, bagging them up, or watching
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the wind scatter them somewhere else.
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Now think back to the spring, most of those leaves were gone.
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Not because someone picked every last one up, but because nature did.
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One of the most important jobs in every ecosystem is recycling.
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When a plant dies, its story isn't over.
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In many ways it's just the beginning.
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Bacteria began breaking apart the tissues.
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Fungi spread microscopic threads through the dead material, earthworms and insects, and
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countless other tiny organisms shred and consume what remains.
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Together they perform more than most essential services of our planet, decomposition.
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And it's easily overlooked because it happens so slowly, but imagine what the world would
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look like if it stopped.
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If every fallen leaf, every dead tree, and every blade of grass, every plant that ever
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lived, just simply piled up year after year, the nutrients locked inside those plants
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would never return to the soil.
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New plants would eventually struggle to grow because new materials that they would need
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are still trapped inside the dead ones.
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Life depends on recycling.
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In fact, decomposition is one of the reasons forests can survive for centuries.
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The trees aren't creating new matter out of nowhere.
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They're constantly reusing what previous generations left behind.
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There's another part of this recycling system that's also important for our climate.
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As decomposers break apart dead plants, much of the carbon those plants captured from
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the atmosphere during photosynthesis, is released back into the air as carbon dioxide.
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Think of it as nature balancing the books.
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The plants removed the carbon from the atmosphere while they grew, and decomposition is returning
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it after they die.
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It's a cycle that's been operating for hundreds of millions of years.
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But here's something interesting.
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This entire recycling system depends on just a few basic ingredients.
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The decomposers need food, moisture, the right temperature, but perhaps most importantly
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they need oxygen, just like we do.
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Bacteria and fungi that are responsible for much of decomposition are living organisms.
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They use oxygen to extract energy from the dead plant material, breaking it apart piece
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by piece.
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Remove enough oxygen and the system begins to slow.
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Scientists see this all the time, that's why food lasts longer and vacuum sealed packaging.
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It's one reason compost piles have to be turned regularly.
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Mixing them introduces fresh oxygen and helps the microbes do their work.
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Even at the bottom of lakes and ponds where oxygen becomes scarce, dead material can often
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accumulate faster than it does on dry land.
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So what happens if you create an environment where oxygen is almost missing, where the
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ground stays saturated year after year, century after century for thousands of years.
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Instead of recycling dead plants back to the environment, nature begins doing something
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entirely different, it starts keeping them.
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If you've ever walked through a peat bog, you're probably picturing something muddy,
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maybe a little unpleasant.
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For centuries people thought exactly that.
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Bogs were wastelands, places to drain, to dry out or to avoid altogether.
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They weren't considered valuable farmland and they certainly weren't viewed as ecological
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treasures.
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But scientists eventually realized they had completely misunderstood what they were looking
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at.
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A peat bog is not simply wet muddy ground, it's a machine, a very slow machine that starts
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with plants.
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Peat bogs are dominated by a remarkable group of mosses, called sphagnum moss.
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At first glance, it doesn't look like much, it's soft and squishy and grows close to
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the ground, but each tiny plant acts like a miniature sponge, capable of holding many
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times its own weight and water.
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Over hundreds and thousands of years these mosses slowly spread across the landscape.
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Like every plant, they grow and die, and every new moss grew on top of the old one.
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Normally, that's where nature's recycling system took over.
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Like we talked about, the leaves in the fall, they get to decomposed, by the following
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spring, they're gone.
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The bacteria and fungi and insects and other decomposers broke the dead plants apart.
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But peat bog changes one critical ingredient, water.
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Because ground remains saturated all year, very little oxygen can penetrate below the surface,
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and without oxygen, decomposition slows to a crawl.
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Instead of completely breaking down, each generation of dead moss is only partially decomposed,
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before another layer grows on top of it.
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And thus, year after year, century after century, millennium after millennium, those thin
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layers accumulate into a thick, dark material called peat.
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And some places that peat can be several meters deep.
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Peat doesn't grow quickly.
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On average, it accumulates about a millimeter a year.
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That's about the thickness of your credit card.
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Now, imagine waiting an entire year for the ground beneath your feet to grow that much.
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Imagine a thousand years, suddenly you've built about three feet of peat.
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Some of the peatlands we see today have been growing steadily since the last ice age
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ended, preserving nearly ten thousand years of earth's history beneath the surface.
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That's why scientists sometimes describe peatlands as living archives.
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The plants today are writing the newest page.
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Everything beneath them is a record of the past, and because those older layers were never
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completely decomposed, they're preserving far more than ancient plants.
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They're preserving something else that's been incredibly important in our changing climate,
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carbon.
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To a scientist, a peat bog is really something like a history book.
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Imagine picking up a book where every page represents another year in earth's past.
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The page on top is today's story.
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The page beneath tells last year's story.
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Keep turning the pages, and eventually you're reading about centuries ago, then thousands
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of years ago.
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That's essentially what scientists see when they examine a peat core.
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Using specialized equipment, researchers can remove a long cylinder of peat from the ground,
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and that core contains layer upon layer of material that's accumulated over thousands
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of years, with the youngest layers on the surface and the oldest buried deep below.
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Each layer is like another page in the archive, and every page contains clues.
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Tiny grains of pollen tell scientists which plants were growing nearby.
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Fragments of insects reveal what kinds of ecosystems existed.
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Microscopic charcoal records ancient wildfires.
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Chemical fingerprints preserved in the peat can even reveal changes in rainfall, temperature
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and atmosphere conditions over time.
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Unlike a written diary, the bog isn't telling us a story, it's simply preserving whatever
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happened, and scientists can learn to read those clues.
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It's similar to how detectives investigate a crime scene.
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One clue won't tell you the whole story, but dozens of clues can all point to the same
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direction.
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That's one reason peatlands have become so valuable to climate scientists.
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Instruments only go back about 150 years in many parts of the world.
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Reliable weather observations become increasingly scarce the farther back you go, but Peatlands
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have been collecting environmental information for thousands of years.
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They allow scientists to compare today's changing climate with periods long before thermometers,
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satellites or weather stations existed, and there's a remarkable clue hidden in every
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layer.
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Remember, those plants never decomposed.
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The carbon they pulled from the atmosphere while they were still alive never fully returned
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to the air after they died.
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It was locked away.
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And the archive kept growing year after year.
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Each new generation of moss, adding a thin layer on top.
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Another page, another small deposit into what became one of Earth's largest natural carbon
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stores.
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Today peatlands cover only 3% of the planet's surface, but collectively they store more
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carbon than all of the world's forests combined.
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Think about that for a moment.
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When we picture places that store carbon, you might imagine towering forests filled with
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enormous trees.
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But some of the most important carbon reservoirs on Earth are only a few inches tall, made of
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moss, slow growing, water log, unassuming moss.
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And they've been quietly storing the remains of ancient ecosystems for thousands of years.
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But every archive depends on one condition.
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It has to remain protected.
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The moment those waterlogged soils are drained and oxygen rushes back in, the pages of the
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history book begin to disappear.
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And that's exactly what's happened in many parts of the world.
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Across Europe, North America and other places, people dug drainage ditches to carry water
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away from these wetlands.
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Governments often encouraged the practice, hoping to create new farmland, grazing land, and
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forests for timber production.
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At first, it probably looked like a success.
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The ground became firmer and it was easier to access and more useful for human activities.
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But beneath the surface, something more important was happening.
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Oxygen was returning.
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As the water drained away, air began moving back into the soil.
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The microbes that had spent centuries barely functioning woke up.
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They had access to oxygen and they began to recycle, to decompose.
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The carbon that had been locked safely underground slowly returned to the atmosphere as carbon
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dioxide.
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Scientists sometimes describe this as a tipping point.
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The peatland hasn't stopped storing carbon, it's changed jobs.
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Now it's putting carbon dioxide back into the atmosphere.
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In climate science, we say it's changed from a carbon sink to a carbon source.
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And in many places in the world, drain peatland now sits noticeably lower than it did decades
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ago because the soil has literally disappeared into the atmosphere as carbon dioxide.
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Dry peat also behaves differently during wildfires.
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Peatland are naturally wet and difficult to burn, but once they dry out, peat can
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become an unexpected fuel source.
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Unlike typical grass fires that burn quickly, peat can smolder underground for weeks, even
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months, and produce enormous amounts of smoke that can be extremely difficult to extinguish,
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because the fire isn't just burning vegetation, it's burning the soil itself.
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And finally there's the water.
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Remember how we described sphagnum moss as a sponge?
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A healthy peatland absorbs rainfall, stores it, and then releases it gradually over time.
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By draining it, instead of soaking up heavy rains like a giant natural reservoir, the
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water moves through the landscape very quickly, increasing erosion, and contributing to flooding
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further downstream.
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So by draining a peatland, you're not just changing one thing, you're changing a lot
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of things.
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You've altered the carbon cycle, the movement of water, the fire risk, you've erased part
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of a natural archive that's taken thousands of years to rebuild.
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Now the encouraging news is that scientists have discovered that many of these changes
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aren't permanent, sometimes helping a peatland to recover is far simpler than you might
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imagine.
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When we talk about environmental restoration, it's easy to imagine something complicated,
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like planting millions of trees or building massive engineering projects, developing new
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technologies.
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Restoring peatland is different, and many cases the first step is very simple.
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Stop the water from leaving.
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Over the past several decades, scientists like Dr. Peter Jones and many others had been
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working to restore peatlands across Wales and England, and in other places around
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the world.
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The process often begins by finding the old drainage ditches that were dug decades or
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even centuries ago.
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Instead of digging new channels, they fill them in.
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Sometimes with peat, sometimes with wood, sometimes with small earthen dams.
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The goal isn't to radically reshape the landscape, it's simply to allow the water to stay
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where it naturally wants to be.
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And as the water table rises, oxygen once again becomes scarce beneath the surface.
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The microbes that have been active start to slow down, and nature's recycling system
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eases back towards the pace that it maintained for thousands of years.
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In time, sphagnum begins to return, the ground becomes wetter, the peat stabilizes,
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and the archive begins preserving itself once again.
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Now, a peatland that took 5,000 years to develop will not be rebuilt in a human lifetime.
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If centuries of accumulated peat have already decomposed, those layers are gone.
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No restoration project is going to recreate that overnight.
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But what restoration can do is prevent additional losses.
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It can protect the archive that remains.
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It can reduce future carbon emissions from degraded peatlands.
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It can improve water quality downstream.
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It can reduce wildfire risk by keeping the landscape wet, and it can help restore habitat
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for plants and animals that depend on these unique ecosystems.
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Perhaps most importantly, restoration reminds us that not every climate solution requires
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inventing something new.
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Sometimes the most effective solution is understanding how nature already works, and give it the
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opportunity to do what it's done for thousands of years.
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It's a reminder that nature often works on time scales very different from our own.
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The challenge for us is deciding whether we will preserve that archive or continue erasing
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pages that can never be written again.
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Peatlands remind us that some of Earth's most important systems don't work on the
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time scale of years or even decades, but on centuries and millennia.
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The choices we make today will determine whether these living archives continue preserving
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Earth's history or slowly lose the stories they've been keeping since the last Ice Age.
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I'm Dr. Mac, and this has been the climate translation.
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If you have a question about the climate that you've been too afraid to ask, or if you
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have a different opinion, I want to hear from you.
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I can use your viewpoints and future episodes.
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You can reach me at theclimatetranslation at gmail.com.
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I'll see you next time.