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Everything is Connected · The Climate Translation

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If you've listened to this podcast for a while, you've probably heard me talk about a lot
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of different ways our climate is changing.
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We've talked about greenhouse gases, aerosols, heat waves, hurricanes, glaciers, El Nino,
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and feedback loops.
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But one question bubbles up after this.
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If scientists understand what's causing the planet to warm?
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Why don't we just cool it back down?
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After all, if your house gets too warm, you just turn the thermostat down.
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Why couldn't we do the same thing for Earth?
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Believe it or not, scientists have been asking that question for decades.
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Some have even proposed a few ways to reflect a small amount of sunlight back into space
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in an effort to cool the planet.
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But a fascinating new study published just a few days ago reminds us that cooling the planet
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may be very different from controlling the climate.
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Because Earth's climate is a vast network of interconnected systems, each influencing
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the others and ways we are still trying to understand.
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So if we change one part of the climate system, what else changes with it?
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Welcome back to the podcast, I'm Dr. Mac, and this is the Climate Translation.
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When I first started teaching climate science, I noticed something interesting.
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Whenever we discussed global warming, someone would eventually raise their hand and ask
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a question, Dr. Mac, if we know the Earth's getting warmer, why don't we just cool it
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back down some way?
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I wish the answer I could provide was simple, but cooling something and controlling it are
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two different things altogether.
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Think about the human body for a moment.
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Imagine someone has a high fever.
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You certainly could lower the temperature by placing them in an ice bath.
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The temperature would drop, but have you cured the illness?
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Well, of course you haven't.
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If treated one's symptom, the underlying problem is probably still there.
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The Earth's climate works the same way.
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The average global temperature is only one measurement of a much larger system.
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Our climate is also made up of winds, ocean currents, clouds, rainfall, snowfall, sea
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ice, plants, animals, and countless interactions between them.
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Imagine walking into a room filled with hundreds of clocks.
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Every clock is connected to every other clock by tiny gears hidden inside the walls.
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Now imagine you reach over and adjust one clock with its hands.
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You might successfully change that one clock, but because they're all connected, you've
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just changed hundreds of others without even realizing it.
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That's what makes climate science so fascinating and so challenging.
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One of the biggest lessons we've learned over the last several decades is that Earth's
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climate isn't a collection of separate systems operating independently.
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It's one enormous interconnected system.
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The atmosphere influences the oceans.
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The oceans influence the atmosphere.
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Changes in sea ice affect sunlight.
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Changes in sunlight affect temperature, which affects evaporation, which affects clouds,
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and the clouds affect how much sunlight reaches the surface.
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Everything is connected to everything else.
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It's probably one reason you've heard me use the word system so often on this podcast,
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because that's how scientists increasingly think about our planet.
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In fact, Earth science programs in colleges and universities across the country are increasingly
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calling their introductory course Earth System Science for this very reason.
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We need to stop looking at it as though it had separate pieces.
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It's one connected machine.
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Now scientists have developed some remarkably creative ideas for reducing global temperatures,
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and some of these ideas may actually work as intended.
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The real question isn't whether we can change one part of the system.
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Instead, it's what else changes at the same time.
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And that's exactly what a fascinating new study set out to investigate.
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It didn't set out to determine whether we could cool the Earth.
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Instead it was interested in if the ways of cooling the Earth might produce different
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outcomes from what was intended.
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And as it turns out, the answer may be yes.
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So how do you test an idea that involves changing the climate of our planet?
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Obviously, you don't.
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At least not in the real world.
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Instead scientists use one of the most powerful tools that they have available, computer models.
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A climate model is really a giant physics experiment inside a computer.
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Researchers programmed the computer with what we know about physics, how the atmosphere
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moves, and how oceans transport heat, how clouds form, and how sunlight interacts with
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the Earth.
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Then they ask an important question.
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What happens if we change just one thing?
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The computer can then simulate and give you some possible results.
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Now you might be asking yourself how can scientists possibly know if what the computer spits
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out would actually occur in the real world?
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This is all hypothetical.
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We've never actually done it.
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And it's a good question.
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Before scientists can trust a climate model to explore the future, they have to ask a
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more important question.
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Can it accurately recreate the past or the present?
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Does it produce realistic El Niño and La Niña events?
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Does it reproduce the seasons?
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Does it simulate major ocean currents and jet streams?
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Does it simulate the rainfall patterns in the way we observe them today?
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So they set up a computer.
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They give it variables that we know describe how the climate was historically, and they
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run it and see what it comes up with.
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If what it produces is wrong, scientists go back and improve the model.
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If what comes up fits with what we actually have observed on the Earth, either in the
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past or now, then they can start asking what if questions with much greater confidence.
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It's not perfect, because no computer model is.
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But it does allow scientists to safely explore ideas that would be impossible or irresponsible
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to test on the real Earth.
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And the study that came out from the University of California - Santa Barbara, researchers wanted
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to compare two different ideas for slightly reducing the amount of sunlight reaching
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the Earth's surface.
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First, they would spread tiny, reflective particles high in the atmosphere, like what happens
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naturally after a large volcanic eruption.
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The second would work much lower in the atmosphere by making certain ocean clouds slightly brighter
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so they would reflect more sunlight back into space.
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Now, if I asked you before this study, if you had two different methods to lower the
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Earth's average temperature by about the same amount, would you expect the climate system
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to respond in the same way?
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Some of you might say yes, after all, cooler is cooler, right?
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But that's not what the researchers found.
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When they looked at only the global average temperature, the two results did appear to
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show similar results, both cooled the planet.
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And if all you cared about was the number on a global thermometer, you might conclude that
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either approach would work equally well.
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But then scientists looked beyond the thermometer.
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And that's where things became interesting.
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Imagine you're a doctor performing annual physicals.
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You find two patients have exactly the same body temperature.
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Does that mean they're equally healthy?
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Of course not.
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One person might have a healthy heart.
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The other may have dangerously high blood pressure.
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Maybe one has the serious infection that hasn't changed their temperature yet.
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Body temperature is an important measurement, but it's only one measurement that matters.
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The climate system works the same way.
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Average global temperature tells us something important, but it doesn't tell us everything.
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Scientists also watch rainfall patterns, ocean circulations, wind patterns, sea ice coverage,
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and ecosystems.
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And one of the most important natural climate cycles on Earth, El Nino La Niña.
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As we've discussed before on this podcast, El Nino isn't simply just a patch of unusually
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warm water in the Pacific Ocean, nor is its alter ego La Niña, an unusually cool patch.
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It's part of a natural cycle that helps organize weather around much of the globe.
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It influences rainfall, storm tracks, droughts and floods, agriculture, and even hurricane
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activity.
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The cycle is one of the major ways our planet redistributes heat around the world.
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In these simulations, one cooling method left that cycle largely intact, and the other
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weakened it substantially.
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Imagine you're trying to cool your house during the middle of the summer.
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You have two options.
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The first is to lower the thermostat by two degrees.
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Every room becomes just a little cooler, and the temperature changes evenly throughout
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the house.
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Now imagine a second approach.
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Instead of adjusting a thermostat, you place a giant air conditioner in one room, but you
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make that room colder.
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Now warm air from the rest of the house starts flowing towards it, doors create air currents
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and rooms warm and cool unevenly.
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Over time, eventually, the air temperature in the house may end up about the same, but
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the way the air moves around the house has completely changed.
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It's similar to what the researchers found.
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The high altitude reflecting method spread the effect relatively evenly across the globe,
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but the low altitude cloud brightening method concentrated much of the cooling over one
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specific part of the Pacific Ocean.
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And that part happened to be just where one of the most important engines driving Earth's
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climate lies.
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As we've talked about before in this podcast, ENSO, the El Nino Southern Oscillation,
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which encompasses El Nino and La Nino, is related to how trade winds strengthen or weaken.
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Warm water shifts east or west across the Pacific, and the atmosphere and the ocean respond.
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Back and forth, over and over again.
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The effects are felt far beyond the Pacific Ocean.
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The cycle helps determine where heavy rains are more likely to fall, where drought may
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develop, how jet streams bend, and how productive some fisheries can become.
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It can even influence hurricane activity from one ocean basin to another.
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It's one natural climate cycle with thousands of miles of influence, and it's why scientists
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pay such close attention to it.
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In this study, the researchers found that when cooling was concentrated over one sensitive
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region of the Pacific, the simulation showed a substantial weakening of that natural rhythm.
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In fact, in some cases, it reduced the natural variability of El Nino by 60 percent.
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That's a remarkable change.
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During many El Nino winters, the jet stream shifts southward across North America.
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That brings increased rain and snowpack to California and the American Southwest.
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That helps replenish reservoirs, and provide water that communities rely on long after
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the winter is ended.
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If the behavior of El Nino changes, scientists would have to ask whether those familiar rainfall
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patterns would change as well.
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The same conditions exist across the Pacific.
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In South and Southeast Asia, seasonal monsoon rains are influenced by the complex interaction
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between the atmosphere and the Pacific Ocean, and those rains support agriculture for hundreds
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of millions of people.
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If one of the major climate systems helping organize those rainfall patterns changes, researchers
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naturally want to know what that would mean for people and ecosystems that depend on them.
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Everything I've talked about on this podcast from sunlight to clouds, to ocean temperatures,
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to atmospheric circulation, it ultimately affects living things.
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Think back to something you probably learned in middle school science.
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Plants need sunlight.
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Without sunlight, photosynthesis slows down.
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The plants produce less energy, they grow more slowly, and of course they affect the
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entire food chain.
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The same principle applies to the oceans.
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The surface waters of our ocean are filled with tiny microscopic organisms called phytoplankton.
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Many people probably have never heard of them, yet they are the most important living organisms
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on the planet.
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They are the foundation of nearly every marine food web.
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Tiny animals eat the phytoplankton, small fish eat those animals, larger fish eat the
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smaller fish, and eventually the energy works his way up the system, from seabirds to marine
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mammals to us.
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In other words, tiny organisms support the entire ocean ecosystem.
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But they do something else just as important.
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Like the plants in your backyard, phytoplankton use sunlight to perform photosynthesis.
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It's an important part of Earth's carbon cycle, and it helps remove carbon dioxide from
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the atmosphere and move it to the ocean.
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So that led researchers to ask a question.
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If we intentionally reduce the amount of sunlight reaching parts of the Earth's surface to
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cool the planet, how might that affect organisms that depend on that sunlight?
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And the study also showed that changing the sunlight in either case affects photosynthesis.
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And influencing photosynthesis, altars marine productivity.
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And if marine productivity changes, there are ripple effects throughout the food web.
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Exactly how large those effects may be, and whether it would occur under all real world
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conditions, that still needs to be researched.
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But one reason studies like this are important is it helps scientists identify questions
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that need answers before anyone should consider deploying any technology.
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It's a powerful reminder that our atmosphere and oceans are not simply a thermostat we
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can turn up and down.
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They're living interconnected systems, and changing one variable can affect many others.
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It's probably the biggest lesson we learned from studies like this.
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When it comes to the Earth's climate, nothing is isolated.
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Everything is connected to everything else.
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We live in a very complex planet.
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Changing even one variable can influence the system and ways we're still working to understand.
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This research doesn't tell us whether geoengineering is the right or wrong answer.
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What it does remind us is that every potential solution deserves careful study.
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Because in a system this complex, good intentions don't always guarantee simple outcomes.
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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, you've been too afraid to ask, or if you have
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a differing 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.