Does Earth Have Limits?: The Chemistry of Pollution, Episode 4

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<v SPEAKER_01>This is Chain Reaction, a podcast from the American Chemical Society, where we link chemistry's past to its future.

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<v SPEAKER_01>I'm your host, Margot Wall.

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<v SPEAKER_01>And I'm Sam Jones.

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<v SPEAKER_01>To start things off, Sam, I'm taking us back to the 1960s.

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<v SPEAKER_01>The smell of hairspray in the air is strong.

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<v SPEAKER_01>Women's hair does are sky high.

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<v SPEAKER_01>Freon is pumping through our refrigerators to cool our milk and government cheese.

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<v SPEAKER_01>And Americans are blissfully unaware of the damage they're causing to the atmosphere, particularly the stratosphere.

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<v SPEAKER_02>I think I know where this is going, Margot hairspray, Freon.

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<v SPEAKER_02>We're getting into CFC territory.

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<v SPEAKER_02>That is chlorofluorocarbons.

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<v SPEAKER_01>Yeah, yeah.

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<v SPEAKER_01>A few short decades following the height of the beehive hairstyle, scientists stumbled upon two major discoveries.

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<v SPEAKER_01>In 1985, scientists with the British Antarctic Survey discovered a hole in the ozone layer, the protective shield in the Earth's stratosphere that absorbs UV radiation from the sun.

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<v SPEAKER_02>I like to think of the ozone layer as basically Earth's sunscreen.

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<v SPEAKER_01>Yes, exactly.

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<v SPEAKER_01>Very high SPF.

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<v SPEAKER_01>And these British scientists had an idea of what was causing the hole, CFCs.

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<v SPEAKER_01>And that was because about a decade before their discovery of the hole in the 1970s, a chemist at University of California Irvine named F.

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<v SPEAKER_01>Sherwood Rowland discovered that CFCs could destroy ozone.

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<v SPEAKER_01>So, knowing that there was a hole in the ozone and that CFCs were likely the cause, the international community jumped into action.

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<v SPEAKER_01>In 1987, very great year, I was born then, um, a UN treaty called the Montreal Protocol mandated a complete halt in CFC production by developed countries by 1996, and that no CFCs should be produced anywhere on the world by 2010.

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<v SPEAKER_01>And over time, the ozone hole has shrunk.

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<v SPEAKER_01>A full recovery is expected by 2066.

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<v SPEAKER_02>I feel like we never get happy stories about the environment.

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<v SPEAKER_02>This is a happy story.

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<v SPEAKER_02>We love it.

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<v SPEAKER_02>It is really amazing what people can do and do really quickly when they work together.

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<v SPEAKER_02>Jonathan Shanklin, who's one of the meteorologists that discovered the hole, is quoted as saying: this discovery was a crucial reminder of the importance in investing in long-term monitoring.

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<v SPEAKER_02>But perhaps the most startling lesson from the ozone hole is just how quickly our planet can change.

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<v SPEAKER_01>Right.

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<v SPEAKER_01>Like how quickly we can change it for the worse and also how quickly we can change it for the better.

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<v SPEAKER_01>Sometimes.

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<v SPEAKER_01>And so in that vein, for the final episode of this mini-series, I was thinking we could take a step back and look at the earth as a whole and how scientists are monitoring its change.

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<v SPEAKER_01>So far, we've talked to chemists about how we understand and mitigate pollution of the air, water, and land.

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<v SPEAKER_01>And now we're gonna bring it all together.

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<v SPEAKER_02>Monitoring the changes of the whole earth.

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<v SPEAKER_02>That is not a job for the faint of heart.

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<v SPEAKER_01>Agreed, but fortunately, I found the perfect person to talk to.

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<v SPEAKER_01>Her name is Catherine Richardson.

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<v SPEAKER_01>She's a professor in biological oceanography at the University of Copenhagen.

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<v SPEAKER_01>And she and her colleagues developed a framework to understand all of the ways we're changing our planet.

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<v SPEAKER_01>It's called the nine planetary boundaries.

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<v SPEAKER_01>So they chose nine categories or systems and then set limits or boundaries on how much they think we can perturb these systems before we harm the stability of them in ways that could have negative consequences.

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<v SPEAKER_02>So the nine categories for which planetary boundaries have been set are stratospheric ozone depletion, like what we just talked about, atmospheric aerosol loading, novel entities, things like new synthetic chemicals, biosphere integrity, land system change, fresh water use, biogeochemical flows, ocean acidification, and one we all know very well, climate change.

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<v SPEAKER_01>Yeah.

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<v SPEAKER_01>Oof, that was that was a lot.

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<v SPEAKER_01>Um it was a list.

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<v SPEAKER_02>It was quite the list.

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<v SPEAKER_01>Yeah.

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<v SPEAKER_01>We are not expecting you to remember all of those.

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<v SPEAKER_01>But unfortunately, as of 2025, we have crossed climate change's set boundary along with six others.

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<v SPEAKER_01>So Catherine and I discuss these nine planetary boundaries, some of which deal directly with managing the chemicals found in nature, and others that focus on the chemicals that we as humans create.

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<v SPEAKER_01>And we get into some of the boundaries that have been crossed and her hope for our management of the planet in the future.

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<v SPEAKER_00>My name is Catherine Richardson.

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<v SPEAKER_00>I'm a professor in biological oceanography at the University of Copenhagen, but I've used the last 30 years or so developing something that we call Earth Science.

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<v SPEAKER_01>So what what does that mean?

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<v SPEAKER_00>Well, Earth System Science is where we instead of looking at geology in one box and physics in one box and chemistry in another one and biology in another, we look at how all of these different sciences work together to create the earth that we know.

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<v SPEAKER_01>So can you give me a little bit of information about your history, like how you got into studying the whole environment?

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<v SPEAKER_00>How did a nice girl like me get into a place like this?

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<v SPEAKER_00>Okay.

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<v SPEAKER_00>I came to Denmark as a marine scientist, and I worked at the Fisheries Institute, and I was concerned with how much carbon gets caught or fixed by the phytoplankton, the little plants in the ocean, and gets into fish.

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<v SPEAKER_00>Why are there more fish here than over there?

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<v SPEAKER_00>And then in the 1990s, I was asked to join a scientific advisory committee for an international program, the International Geosphere Biosphere Program.

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<v SPEAKER_00>And I tell you, the gods were there.

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<v SPEAKER_00>Paul Krutzen, who of course got a Nobel Prize for being part of the team that figured out what we were doing to the ozone layer, Bert Bolin, who was the first chair of the UN Climate Panel IPCC.

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<v SPEAKER_00>And it occurred to me while we were looking at all these different projects that were in this program that I had only been looking at this tiny little part of the carbon cycle, how much carbon goes from phytoplankton to fish, and then I couldn't care less what happened to the carbon.

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<v SPEAKER_00>And then I realized, oh, wait a minute, we could keep looking at this and look at the whole cycle.

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<v SPEAKER_00>And suddenly my little phytoplankton became important for climate.

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<v SPEAKER_00>And it was a really exciting time in the 90s because that was when it was in 1999 that a Russian-French research team took an Antarctic ice core and were able to show that the temperature of the Earth for the last 450,000 years is directly correlated to the amount of greenhouse gas there was in the atmosphere.

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<v SPEAKER_00>So I think this was the data that really made scientists sit up on their chairs and say, ah, we got a problem here.

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<v SPEAKER_01>So was that the impetus for you coming up with these nine planetary boundaries?

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<v SPEAKER_00>Yes, that's absolutely that's what it grew out of.

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<v SPEAKER_00>Basically, the idea is our ancestors they started out by throwing their waste wherever it was produced and by taking whatever they thought they needed from nature.

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<v SPEAKER_00>And then they realized that for their own sakes, they were going to have to manage their relationship with the environment around them.

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<v SPEAKER_00>Right.

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<v SPEAKER_00>And then we got to be more people, and we could say, well, that's not enough to do it locally.

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<v SPEAKER_00>We need regional environmental management as well, because if you're going to have clean air and water in one town, then you can't let the neighboring communities pollute the water or the air around you.

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<v SPEAKER_00>So regional environmental management was born.

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<v SPEAKER_00>And we believe that when you look at the the human impacts on the earth system, when you look at those, you can see there's now a need for doing management of our relationship with the planet as a whole for our own sake.

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<v SPEAKER_00>And I guess that's pretty obvious.

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<v SPEAKER_00>When we have a global economy, we're linked to every other person and every other organism on Earth.

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<v SPEAKER_00>This is not about save the planet.

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<v SPEAKER_00>This is about save the way the planet is so that we can continue to thrive on it.

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<v SPEAKER_00>So the planetary boundaries are actually designed to help develop management of the human-earth relationship.

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<v SPEAKER_00>Humans in our current form have been on this planet for something like a quarter of a million years.

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<v SPEAKER_00>It's only in the last 12,000 years that everything we associate with modern civilization evolved.

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<v SPEAKER_00>I mean, we're talking Stone Age, Bronze Age, Iron Age, Neolithic Revolution, written language, all of that happened in the last 12,000 years.

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<v SPEAKER_00>And many anthropologists think that one of the reasons that we could do that was because the conditions, the environmental conditions were so stable.

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<v SPEAKER_00>And in fact, during the last 12,000 years, the average temperature on Earth has only varied by plus minus a half a degree centigrade.

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<v SPEAKER_00>Wow.

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<v SPEAKER_00>And now we're barreling towards an increase.

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<v SPEAKER_00>We say we want to keep it at 1.5 or 2, but you know.

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<v SPEAKER_00>So our starting point for the planetary boundaries is to say it would be unwise of us to knowingly do something, to change something in the Earth's overall environment that could change the conditions, so they might not still support us.

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<v SPEAKER_00>Right.

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<v SPEAKER_00>So we then say, okay, what are the important subsystems or processes in this earth system that are maintaining it in the conditions that it's in?

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<v SPEAKER_00>And we identify nine, and those are the ones that we call planetary boundaries.

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<v SPEAKER_00>We have two core boundaries, that is to say, climate and biodiversity.

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<v SPEAKER_00>Since life evolved about three and a half billion years ago, it's been the interaction between life or biodiversity and climate that have created the conditions on Earth.

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<v SPEAKER_00>And if you don't think life was important, then ask yourself where we'd be without oxygen or where we'd be without an ozone layer.

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<v SPEAKER_00>And, you know, when when green plants evolved, there was suddenly a way to get CO2 out of the atmosphere and the earth cooled.

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<v SPEAKER_00>So those we call our core boundaries.

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<v SPEAKER_00>But then we identify seven other things that we do or processes that we impact in the Earth's system.

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<v SPEAKER_00>It's use of water, it's felling of forest or land use, it's acidification of the ocean, it's the ozone, it's changes in the big geochemical cycles for nitrogen and phosphorus.

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<v SPEAKER_00>And then we try and assess what would be a safe level of perturbation or how much is too much.

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<v SPEAKER_00>I mean, you can look at all of the ones that we have and say, hmm, I could imagine a world where the climate is so changed we can't be here, or hmm, I could imagine a world where air pollution is so great that we couldn't be here.

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<v SPEAKER_00>I mean, think what happened to the poor dinosaurs.

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<v SPEAKER_00>Yeah.

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<v SPEAKER_00>And so then we go in and say, where should the limit be set?

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<v SPEAKER_00>And for most of them, we do it by looking how do these things perform under different climate conditions and in other periods of the Earth's history, so we get an idea of their sensitivity.

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<v SPEAKER_01>Okay.

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<v SPEAKER_00>And, you know, scientists being scientists, they often go, are you absolutely sure about that, Bob?

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<v SPEAKER_00>And you know, the answer is no.

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<v SPEAKER_00>Right.

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<v SPEAKER_00>We're doing the best we can.

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<v SPEAKER_01>Right.

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<v SPEAKER_01>You're doing some guesswork, but you just want to be in the ballpark.

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<v SPEAKER_00>Exactly.

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<v SPEAKER_00>I think we need to work on the what we call control variables and what we can measure and how we can how we can plot the human impact against the earth.

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<v SPEAKER_00>And and the reason I say that is, you know, if you want to know what the the greenhouse gas concentration or the CO2 concentration in the atmosphere is, no problem.

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<v SPEAKER_00>You just go to the internet and you get it from two hours ago.

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<v SPEAKER_00>But if you want to know the state of the ozone hole or of aerosols in the atmosphere, there's no organized collection of data in the same way.

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<v SPEAKER_00>So there's, you know, one group of scientists that's been working on it here and another one there, and they're using different methods.

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<v SPEAKER_00>And so for some of them, the databases at the moment isn't great.

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<v SPEAKER_00>That needs to be improved.

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<v SPEAKER_00>And for some of the things we'd really like to have, those kinds of data just don't exist at the moment.

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<v SPEAKER_00>So what we've done, at least for the land, we've said, okay, where life is really important is when it's catching the energy coming from the sun and making it available to the rest of life.

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<v SPEAKER_00>So we look at how much photosynthesis was there every year in the 10,000 years before the industrial revolution.

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<v SPEAKER_00>And then we look at it today, and we can say, okay, if there's more photosynthesis because we've got the fertilization effect, and then we look at what we're preventing happening because I'm willing to bet the building you're sitting in doesn't have a lot of photosynthesis going on on its roof.

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<v SPEAKER_00>No.

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<v SPEAKER_00>And neither does the road outside your house and so on.

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<v SPEAKER_00>Yeah.

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<v SPEAKER_00>So a lot of our infrastructure and even our farming, we're actually reducing the amount of photosynthesis happening on Earth.

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<v SPEAKER_00>But then we are we are also using a lot of that energy ourselves.

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<v SPEAKER_00>A third of the energy that was available for life by photosynthesis at the time of the Industrial Revolution.

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<v SPEAKER_00>A third of the energy that was available for us and all other living organisms is now being used by us.

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<v SPEAKER_00>And yet we want to use more biomass.

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<v SPEAKER_00>Everyone's, oh, we're gonna have biomass to to heat us, and oh, we're gonna have biomass to make plastic.

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<v SPEAKER_00>But there's a limited amount of energy made available for life.

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<v SPEAKER_00>And the more of it we take, the less of it is available for the rest of biodiversity.

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<v SPEAKER_00>I've begun to realize that when we cut a tree, we're taking someone else's food.

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<v SPEAKER_00>So we better use it as efficiently as possible and only in situations where there isn't an alternative.

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<v SPEAKER_00>So for me, you know, I it I it tells me that when we need innovation, we need to think about first of all making sure that we're using photosynthetic products as efficiently as possible.

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<v SPEAKER_00>I'm not sure, for example, that building with wood is really very sustainable because the only thing we really want from the wood is the structure and the strength.

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<v SPEAKER_00>We don't need all the sugars and all the other things that are sitting in it.

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<v SPEAKER_00>We could refine that wood so that we get the fibers and make building materials out of the fibers and then use the other materials for other purposes.

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<v SPEAKER_00>What are we not being efficient about?

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<v SPEAKER_00>Yeah, the other way is to make more photosynthesis.

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<v SPEAKER_00>Well, how can we make more photosynthesis?

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<v SPEAKER_00>Yeah, we could probably we could probably change the way we use our land and make more land available.

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<v SPEAKER_00>We might be able to put it on roofs and so on, but we're not smart enough to do photosynthesis ourselves yet.

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<v SPEAKER_00>I know many people have been trying for a very long time, and maybe one day they'll do it, but we have to remember in three and a half billion years, photosynthesis only evolved once, and it's a very inefficient process.

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<v SPEAKER_00>So it's not just something you go to the lab and say, now I'm gonna do photosynthesis.

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<v SPEAKER_00>And you know, we're working very hard just to be able to capture CO2 from the atmosphere, let alone make it into something that can transfer energy into life.

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<v SPEAKER_00>I mean, that's a big step.

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<v SPEAKER_00>So, in the absence of being able to do photosynthesis ourselves, I do think that we're clever enough to be able to help plants do photosynthesis places where they mostly maybe wouldn't normally do it.

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<v SPEAKER_00>For example, on your roof, but also in bioreactors.

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<v SPEAKER_00>You know, we can make animal food, we can make people food, you know, with algae in reactors.

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<v SPEAKER_00>I mean there are there are lots of there are lots of I think possibilities for innovation.

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<v SPEAKER_00>And I absolutely see a role for for for chemists in in all of this.

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<v SPEAKER_00>I mean, we need chemists in be in order to be able to figure out how we can use our photosynthetic products more efficiently.

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<v SPEAKER_00>We need chemists to be able to help us understand if we can create more photosynthesis in some way.

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<v SPEAKER_01>So I wanted to pivot to maybe some of the other boundaries to talk about them in a little more detail.

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<v SPEAKER_01>Um, because I don't know much about them.

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<v SPEAKER_01>So, for instance, uh something I'm sure that you thought about a lot coming from your background in ocean science, ocean acidification.

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<v SPEAKER_01>Um, is this a a big problem in the scale of things and and why is it happening actually?

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<v SPEAKER_00>Well, it's a huge problem.

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<v SPEAKER_00>And the ocean has not been as acidic as it is right now for over the last 20 million years.

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<v SPEAKER_00>And it's because of climate change.

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<v SPEAKER_00>When we put CO2 into the atmosphere, it obviously increases the partial pressure of CO2 in the atmosphere.

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<v SPEAKER_00>And when you increase the partial pressure on one side of a boundary, you know, you're trying to get into equilibrium on the other side of the boundary.

00:17:42.559 --> 00:17:46.480
<v SPEAKER_00>And in this case, the other side of the boundary is the surface of the ocean.

00:17:47.039 --> 00:17:53.680
<v SPEAKER_00>So as we put more CO2 into the atmosphere, we're putting more CO2 into the surface of the ocean.

00:17:53.839 --> 00:17:59.039
<v SPEAKER_00>And obviously, we're creating carbonic acid because that's what happens when you put CO2 into water.

00:17:59.279 --> 00:17:59.920
<v SPEAKER_00>It's like soda.

00:18:00.160 --> 00:18:00.720
<v SPEAKER_00>Yeah, exactly.

00:18:00.880 --> 00:18:01.119
<v SPEAKER_00>Exactly.

00:18:01.440 --> 00:18:02.240
<v SPEAKER_00>It's acidic, yeah.

00:18:02.480 --> 00:18:11.039
<v SPEAKER_00>And and a lot of people go to the dentist and discover that they have they have acid damage on their teeth because they're drinking too much carbonated beverages.

00:18:11.200 --> 00:18:13.119
<v SPEAKER_00>And it's the same problem in the ocean.

00:18:13.200 --> 00:18:17.359
<v SPEAKER_00>There's very many organisms in the ocean that make calcium carbonate.

00:18:17.440 --> 00:18:20.319
<v SPEAKER_00>And calcium carbonate doesn't like acid.

00:18:20.559 --> 00:18:38.720
<v SPEAKER_00>Actually, on the west coast of the United States, for example, it is an economic problem for oyster hatcheries because oysters, I'm sure you can imagine that the tiny oysters have a paper thin shell, and if they get into water that's too acidic, then they don't have it any longer.

00:18:39.519 --> 00:18:43.680
<v SPEAKER_01>So there's a boundary called novel entities, and it's very mysterious.

00:18:49.279 --> 00:18:50.640
<v SPEAKER_01>Oh yeah, we're getting there.

00:18:50.799 --> 00:18:51.839
<v SPEAKER_01>Novel entities.

00:18:51.920 --> 00:18:54.880
<v SPEAKER_01>So I'm guessing these are things made through chemistry.

00:18:55.359 --> 00:18:56.319
<v SPEAKER_00>Not all of them.

00:18:56.559 --> 00:19:02.720
<v SPEAKER_00>Basically, it's describing things that are now found on Earth that wouldn't be there if we weren't there.

00:19:03.039 --> 00:19:08.319
<v SPEAKER_00>Plastic, synthetic chemicals, certain forms of radioactivity, and so on.

00:19:08.559 --> 00:19:13.039
<v SPEAKER_00>But yes, synthetic chemicals are clearly, clearly in focus.

00:19:13.200 --> 00:19:29.599
<v SPEAKER_00>Now, this has been a really, really tough one, and we didn't really know how to deal with it because clearly history shows us that the only truly safe operating space would be not to put them into the open environment at all.

00:19:29.839 --> 00:19:46.240
<v SPEAKER_00>I mean, we've we've been surprised by DDT, we've been surprised by the CFCs, we're surprised at the moment by by so the only truly safe operating space is to not get it into the open environment.

00:19:46.480 --> 00:19:50.720
<v SPEAKER_00>But we're, you know, pragmatic enough to realize that's not gonna happen.

00:19:51.279 --> 00:20:01.759
<v SPEAKER_00>So the next best would be to say we should not put anything into the open environment that hasn't been thoroughly tested under the conditions where it will end up.

00:20:02.559 --> 00:20:13.200
<v SPEAKER_00>And and you know, even that's not you know, that's not a sure thing because the CFCs had been tested, just not at the temperatures and pressures that you have in the stratosphere.

00:20:13.359 --> 00:20:15.119
<v SPEAKER_00>So they surprised us.

00:20:15.680 --> 00:20:23.039
<v SPEAKER_00>But nevertheless, we go in and say nothing foreign should be put into the into the environment without being thoroughly tested.

00:20:23.119 --> 00:20:40.000
<v SPEAKER_00>And then we had a look at the the REACH database, which is the EU database on on chemicals, and it turned out that over 80% of the chemicals on that list have been in use for over 10 years and have never been tested.

00:20:41.039 --> 00:20:49.839
<v SPEAKER_00>So so we arrive at the conclusion that we're we're on the wrong side of the planetary boundary for for novel entities.

00:20:50.240 --> 00:21:03.359
<v SPEAKER_00>But that's a completely different kind of boundary than for any of the others, but it's also a completely different kind of um planetary boundary because it represents something that wasn't a part of the Earth system.

00:21:03.519 --> 00:21:10.640
<v SPEAKER_00>Yeah, it has the potential to completely change the interaction between the energy balance and life.

00:21:11.039 --> 00:21:11.920
<v SPEAKER_01>It is wild.

00:21:12.000 --> 00:21:23.839
<v SPEAKER_01>I mean, just thinking from the chemical side of it, we're just like making these things that have never existed before on our planet, like so many, so many different chemicals that are just totally new.

00:21:24.240 --> 00:21:28.240
<v SPEAKER_00>And so many of them have been wonderful for us and they do wonderful things for us.

00:21:28.319 --> 00:21:30.799
<v SPEAKER_00>And I'm certainly not saying that they shouldn't be there.

00:21:31.039 --> 00:21:31.359
<v SPEAKER_02>Yeah.

00:21:31.680 --> 00:21:39.680
<v SPEAKER_00>But I do think we need to be much more humble about what we do with them and and where we leave them behind us.

00:21:40.000 --> 00:21:45.680
<v SPEAKER_00>You can you can look at the pictures of the earth from space, and you can see, oh, there's no umbilical cord.

00:21:46.160 --> 00:21:53.519
<v SPEAKER_00>And if there's no umbilical cord, it means that once we've used what's here, we're not gonna get any more.

00:21:53.599 --> 00:21:57.200
<v SPEAKER_00>And it also means that we can't really get rid of our waste.

00:21:57.359 --> 00:21:59.359
<v SPEAKER_00>We thought the greenhouse gas waste was gone.

00:22:00.240 --> 00:22:00.400
<v SPEAKER_00>Not.

00:22:00.480 --> 00:22:02.160
<v SPEAKER_00>It's in the atmosphere around us.

00:22:02.640 --> 00:22:09.200
<v SPEAKER_00>And you know, it took us, I can't believe it took us 60 years to realize that plastic was in the ocean.

00:22:09.359 --> 00:22:16.720
<v SPEAKER_00>Come on, we've been using plastic since the 1950s, knowing full well it's basically non-degradable in nature.

00:22:16.799 --> 00:22:17.839
<v SPEAKER_00>That's why we like it.

00:22:18.000 --> 00:22:28.640
<v SPEAKER_00>We've had pictures of the Earth from space since 1968 that show us clearly that there's no pipe that's gonna take it away, and over 70% of the Earth is ocean.

00:22:28.960 --> 00:22:32.000
<v SPEAKER_00>Come on, where did we think the plastic was gonna go?

00:22:32.160 --> 00:22:33.839
<v SPEAKER_00>It's not rocket science.

00:22:34.000 --> 00:22:47.359
<v SPEAKER_00>And and you know, most of us have been in a biology lab at some point in our careers where we've been given a little bottle with some media, and we should put a little organism in it, and we should see what happened.

00:22:47.440 --> 00:22:50.079
<v SPEAKER_00>And there's lots of nutrients in that media.

00:22:50.319 --> 00:22:52.799
<v SPEAKER_00>It starts out, grows very, very slowly.

00:22:52.880 --> 00:22:54.640
<v SPEAKER_00>We call that the lag phase.

00:22:54.880 --> 00:22:57.119
<v SPEAKER_00>And then it goes into exponential phase.

00:22:57.200 --> 00:23:11.359
<v SPEAKER_00>It gets, you know, grows very quickly, but then it begins to run out of resources and it begins to stabilize the stationary phase, and in the end it dies, and it dies because it becomes poisoned by its own waste products.

00:23:11.599 --> 00:23:16.319
<v SPEAKER_00>And if you think about humans, we're also in a closed system.

00:23:17.759 --> 00:23:22.319
<v SPEAKER_00>And we've had our lag phase, we've had our exponential phase.

00:23:22.559 --> 00:23:25.759
<v SPEAKER_00>Demographers agree we're going into a stationary phase.

00:23:26.079 --> 00:23:32.240
<v SPEAKER_00>And the question is can we prevent ourselves from becoming poisoned by our own waste products?

00:23:32.640 --> 00:23:40.000
<v SPEAKER_01>So when you first published this framework back in in 2009, there were three boundaries that had already been crossed.

00:23:40.079 --> 00:23:45.039
<v SPEAKER_01>There was climate change, biosphere integrity, and biogeochemical flows.

00:23:45.519 --> 00:23:49.039
<v SPEAKER_01>How has that changed since then?

00:23:49.680 --> 00:24:00.079
<v SPEAKER_00>The number of boundaries that have been transgressed, we found only three in the first study, we found more in the second, and we found six in the third.

00:24:00.880 --> 00:24:09.119
<v SPEAKER_00>One of the reasons that we found more is that we didn't actually have metrics in the two first papers for some of the boundaries.

00:24:09.200 --> 00:24:13.440
<v SPEAKER_00>For example, the aerosols, air pollution, particles in the atmosphere.

00:24:13.680 --> 00:24:18.960
<v SPEAKER_00>Um, so so the reason they're increasing isn't totally because things are getting worse.

00:24:19.119 --> 00:24:21.759
<v SPEAKER_00>We're also getting better about measuring.

00:24:22.000 --> 00:24:26.240
<v SPEAKER_00>But the ones that are transgressed are getting even more transgressed.

00:24:26.559 --> 00:24:28.000
<v SPEAKER_01>It seems kind of dire.

00:24:28.640 --> 00:24:34.880
<v SPEAKER_01>I feel like it must be kind of depressing, I I'm assuming, to do this work.

00:24:35.279 --> 00:24:36.400
<v SPEAKER_01>I don't think so, Margot.

00:24:36.559 --> 00:24:37.599
<v SPEAKER_00>I really don't.

00:24:37.759 --> 00:24:38.799
<v SPEAKER_00>I really don't.

00:24:39.039 --> 00:24:48.960
<v SPEAKER_00>First of all, I just don't believe that humanity would be so irresponsible as to not respond, to not act on the knowledge that we have.

00:24:49.119 --> 00:24:58.559
<v SPEAKER_00>And we've always said that knowledge is power, and we were on the wrong side, or at least very close to being on the wrong side for the ozone hole in the 1990s.

00:24:58.720 --> 00:24:58.960
<v SPEAKER_01>Yeah.

00:24:59.200 --> 00:25:01.039
<v SPEAKER_00>And we're back in the right area now.

00:25:01.200 --> 00:25:08.160
<v SPEAKER_00>So, so so being on the wrong side is not the same as saying that that there's an imminent disaster.

00:25:08.559 --> 00:25:08.720
<v SPEAKER_00>Right.

00:25:08.799 --> 00:25:12.160
<v SPEAKER_01>It's not a boundary that you can't perhaps go back on.

00:25:12.559 --> 00:25:14.000
<v SPEAKER_00>It's sort of like your blood pressure.

00:25:14.160 --> 00:25:20.319
<v SPEAKER_00>If your blood pressure is over 120 over 80, it's no guarantee you're gonna have a heart attack or a stroke, but it does increase the risk.

00:25:20.480 --> 00:25:21.920
<v SPEAKER_00>So we try and bring it down.

00:25:22.079 --> 00:25:25.440
<v SPEAKER_00>And that's the way I look to like to look at planetary boundaries.

00:25:25.839 --> 00:25:36.160
<v SPEAKER_01>But we've known that increasing the temperature of the earth through greenhouse gases is is is bad and is going to alter the climate in in ways that are not good.

00:25:36.319 --> 00:25:40.559
<v SPEAKER_01>And yet, like we haven't decreased the amount that we're releasing.

00:25:40.640 --> 00:25:45.680
<v SPEAKER_01>We've made some strides, but like we're still gonna cross that that you know two degrees Celsius boundary.

00:25:46.000 --> 00:25:48.640
<v SPEAKER_01>I mean, when you say we, who is we?

00:25:49.119 --> 00:25:50.000
<v SPEAKER_00>The human race.

00:25:50.319 --> 00:25:50.880
<v SPEAKER_00>Well, yeah.

00:25:51.039 --> 00:25:56.799
<v SPEAKER_00>Some scientists have known for a long time, and it's taken some time for more people to understand.

00:25:57.039 --> 00:26:05.039
<v SPEAKER_00>But in the same way that there are natural science tipping points, such as losing the corals, there are also social tipping points.

00:26:05.200 --> 00:26:15.680
<v SPEAKER_00>And social tipping points happen, you don't have to have everyone to agree, but you have to have a certain percentage of the population that wants things to change.

00:26:15.920 --> 00:26:30.720
<v SPEAKER_00>Now, for example, if you look globally at green energy, we see that the investment in green energy is double that of the investment in fossil fuels.

00:26:30.960 --> 00:26:33.440
<v SPEAKER_00>So I'm not as pessimistic as you are.

00:26:33.519 --> 00:26:39.599
<v SPEAKER_00>Um, there's not very much good you can say about getting old, but you do have experience.

00:26:39.759 --> 00:26:46.720
<v SPEAKER_00>And I have I have seen things changing very, very much in the time that I've been working on this.

00:26:47.039 --> 00:26:57.119
<v SPEAKER_00>We have to believe that there are still possibilities, and that's why this 71-year-old woman still works 60 to 70 hours a week on this agenda.

00:26:57.519 --> 00:27:04.720
<v SPEAKER_00>I really, I really do believe it's possible, and and I feel I need to do it for my children and my grandchildren.

00:27:10.640 --> 00:27:12.000
<v SPEAKER_02>I love how she says that.

00:27:12.160 --> 00:27:24.319
<v SPEAKER_02>I think, you know, as someone who recently had a kid, I think a lot of times we're faced with things that feel less hopeful, and it's nice hearing from someone who works so hard and is so hopeful.

00:27:24.480 --> 00:27:24.720
<v SPEAKER_02>Yeah.

00:27:24.960 --> 00:27:36.319
<v SPEAKER_02>I mean, one of the big picture things I gathered from that episode was that chemists and chemistry have over the course of history, um, and even today, been part of the pollution problem.

00:27:36.880 --> 00:27:41.519
<v SPEAKER_02>But I do see that now they're also playing this essential role in finding solutions.

00:27:41.759 --> 00:27:42.079
<v SPEAKER_02>Right.

00:27:42.319 --> 00:27:51.599
<v SPEAKER_01>And sometimes the influence of chemistry is obvious, like with the ozone hole, where we just needed to stop producing these CFCs and use alternatives.

00:27:52.000 --> 00:27:55.039
<v SPEAKER_01>With novel entities, it's a similar story.

00:27:55.119 --> 00:28:00.799
<v SPEAKER_01>Like we need to find alternatives to producing long-lasting waste and find ways of cleaning it up.

00:28:00.960 --> 00:28:06.000
<v SPEAKER_01>But for some of the other boundaries, we could really use some breakthroughs in chemistry.

00:28:06.319 --> 00:28:06.559
<v SPEAKER_02>Right.

00:28:06.640 --> 00:28:12.799
<v SPEAKER_02>Like what Catherine mentioned about capturing carbon and even better, harvesting it for energy.

00:28:14.400 --> 00:28:19.680
<v SPEAKER_01>So, Sam, we just scratched the surface of the nine planetary boundary framework.

00:28:19.839 --> 00:28:27.279
<v SPEAKER_01>So if you want to learn more about the boundaries, how they're monitored, and which have been crossed, check out the link in our show notes.

00:28:27.599 --> 00:28:28.640
<v SPEAKER_01>I definitely will.

00:28:28.880 --> 00:28:31.839
<v SPEAKER_01>We'll be back with the next miniseries in a few weeks.

00:28:32.079 --> 00:28:39.759
<v SPEAKER_01>But before then, be on the lookout for a preview of that mini-series and a bonus episode about anthrax decontamination.

00:28:40.160 --> 00:28:42.000
<v SPEAKER_01>Very interesting, kind of scary.

00:28:42.240 --> 00:28:42.640
<v SPEAKER_01>Yeah.

00:28:42.960 --> 00:28:48.640
<v SPEAKER_01>In the meantime, if you like the show, give us a rating and review on Apple Podcasts.

00:28:48.880 --> 00:28:51.279
<v SPEAKER_01>It helps other people hear about us.

00:28:51.440 --> 00:28:52.720
<v SPEAKER_01>So thank you.

00:28:54.640 --> 00:28:59.200
<v SPEAKER_01>This was Chain Reaction, a podcast by the American Chemical Society.

00:28:59.440 --> 00:29:01.759
<v SPEAKER_01>Our executive producer is Sam Jones.

00:29:01.920 --> 00:29:04.160
<v SPEAKER_01>Our lead producer is me, Margot Wall.

00:29:04.480 --> 00:29:06.400
<v SPEAKER_01>Research was done by Beck Rolldon.

00:29:06.559 --> 00:29:08.480
<v SPEAKER_01>Fact checking by Michelle Boucher.

00:29:08.640 --> 00:29:11.599
<v SPEAKER_01>Production help from Michael David and Matt Radcliffe.

00:29:11.759 --> 00:29:13.759
<v SPEAKER_01>The theme song was by Dee Peterschmidt.

00:29:13.839 --> 00:29:19.759
<v SPEAKER_01>And of course, you can always email us at chainreaction atacs.org.