Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall. 

Today, we have a thought experiment on our minds. What would happen if we stopped creating greenhouse gas emissions right now? Would climate change be over?

We had Isha Chawla and Fatima Husain from our Possibly team look into this. Welcome, Isha and Fatima!

Isha Chawla: Hi, Megan!

Fatima Husain: Hello!

Megan Hall: Okay, so theoretically, if we brought all our emissions down to zero today — would global warming just stop?

Isha Chawla: To get to the bottom of that question, we reached out to…

Amanda Lynch, I’m a Professor of Earth, Environmental and Planetary Sciences at Brown University.

Fatima Husain: And Amanda says to answer this question, you have to understand how emissions affect our climate. 

Isha Chawla: When greenhouse gas emissions go up into the air, they stop heat from escaping, which makes the planet warmer. You can imagine them as an invisible blanket.

Fatima Husain: But, there’s a delay between when that happens and when we actually notice a change in temperature. 

Amanda Lynch: it’s like heating up a cast iron pan, instead of heating up an aluminium pan.

Isha Chawla: You know how cast iron stays cold for a while, even after you’ve turned on the burner? The Earth is like that too. 

Amanda Lynch: And then when you turn the heat off, that cast iron pan stays hot for a lot longer than the aluminum pan. 

Fatima Husain: So basically, the Earth takes a while to warm up, but then it holds onto that heat for a long time. 

Megan Hall: Where is the Earth holding onto all of this heat?

Isha Chawla: Well, mostly in water, and more specifically, in the ocean. Our seas trap over 90% of the heat that we’ve been putting in the atmosphere. 

Amanda Lynch: the deep oceans are vast. And they hold some of that heat for decades and hundreds of years.

Fatima Husain: But those deep oceans are also constantly moving, which means the heat that’s been trapped deep below doesn’t stay there forever. It eventually gets released as the water comes back up to the surface.

Isha Chawla: Which means there’s a lot of heat that’s just sort of hiding in the water. It’s not gone away, it’s just taking its time to come back up again.

Megan Hall: So, this is a complicated way of telling me that we’ll experience the results of climate change LONG after we stop creating greenhouse gas emissions?

Fatima Husain: Yes. There’s so much heat already sort of baked into the Earth that it will take a while to cool off. 

Isha Chawla: And to make things worse, greenhouse gas emissions tend to linger. In the case of carbon dioxide, it can take centuries before it’s eventually removed from the atmosphere.

Megan Hall: Ok, so climate change is here for a while, no matter what we do. But, if we DID get rid of all of our emissions today, how long would it take to see the effects of that change?

Fatima Husain: Amanda says it could take decades. At least until 2050.

Amanda Lynch: there’s certainly climate change that we’ve committed to between now and 2050, that we really, we just have to work out how to cope with. But then what happens after 2050 is still in our hands.

Isha Chawla: Knowing this, Amanda says we have to accomplish two things at the same time — do whatever we can to decrease the emissions that cause climate change AND prepare for the inevitable global warming that is to come.

Amanda Lynch: I don’t want people to feel that if we do make dramatic changes to our emissions regimes, and they don’t see a response, it was a waste of time, and they may as well give up. And so it’s about managing expectations.

Fatima Husain: That means not only doing things like investing in wind and solar power, but also redesigning the ways we live and work to prepare for the inevitable effects of a warmer planet. 

Isha Chawla: Amanda also says we should be working on technologies that can pull carbon dioxide out of the air and store it underground.

Megan Hall: Got it! Thanks, Isha and Fatima!

That’s it for today. For more information, or to ask a question about the way you recycle, use energy, or make any other choice that affects the planet, go to the public’s radio dot org slash possibly. Or subscribe to us wherever you get your podcasts.

Possibly is a co-production of the Institute at Brown for Environment and Society and the Public’s Radio.

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