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Is it too late?

This week, Science Node debuts a new series on climate change that we’re calling Is it too late? We've known about climate change for decades, but many people are still apathetic to it. Even worse, some believe that it's simply too late to do anything about this crisis. 

We want to examine and challenge that assumption.

Over the course of this series, we will interview a diverse set of experts to better understand the climate crisis we face. What’s more, we’ll be asking various forms of a globally imperative question: Is it too late to save organized human life on planet Earth?

For this article, we spoke with Dr. Ben Kravitz. An assistant professor in the Department of Earth and Atmospheric Sciences at Indiana University, one of Kravitz’s main focuses is climate engineering. This is the (currently theoretical) process of artificially altering the environment to counter climate change and buy us more time to solve the crisis.

It’s a controversial topic to some, but Kravitz is interested to learn more about it. He thinks that if we want to survive the climate crisis, we’ll have to at least consider every potential solution.

What are the defining features of the climate crisis and humanity's response to it? 

Climate change is affecting, or poised to affect, pretty much every aspect of our lives. We're seeing droughts and floods, so-called polar vortex events, changes in hurricane frequency and intensity - the list goes on and on. One of the things that I think about is reliability of weather and climate predictions.

<strong>Ben Kravitz</strong> is an assistant professor in the Earth and Atmospheric Sciences Department at Indiana University.

Trees are changing their leaves at different times. Birds are migrating differently, and maybe not in concert with their food supply. Shifts to these ecosystems have really important cascading effects. And farmers need to be able to predict when they should plant so that we all have enough to eat. A lot of that historical knowledge is getting upset.

There has been some movement on addressing climate change. The Paris Accord was monumental, and there is evidence that many countries are not only on track to reach their pledges, but are coming up with new ones. I just saw a paper within the last week about how greenhouse gas changes are less than the "no climate policy" scenario, exactly because a lot of places have implemented a climate policy.

"If climate engineering is all we do, and we don't curb our greenhouse gas emissions, we have to keep doing climate engineering in increasing amounts forever. That's not a sustainable solution to climate change." ~ Kravitz

There's evidence that there's a will to do something about climate change, so it is possible. That said, the problem of climate change is so massive and embedded in the way we live that getting to net zero emissions is a daunting task. While I want to be optimistic about what people have done so far, it's unfortunately not enough to prevent more climate change.

Can you explain what climate engineering/geoengineering is? What are some possible scenarios for future action that interest you?

Climate engineering is a set of technologies designed to deliberately, temporarily modify the climate system to prevent some of the worst effects of climate change. Because climate change is such a daunting problem, solutions (like reducing our greenhouse gas emissions) will maybe take a while to implement.

<strong>The Greenhouse Effect</strong> is a process where gasses trap large amounts of heat in Earth's atmosphere. Putting a stop to these emissions will take a lot of time that we don't have. Climate engineering might buy us that time.

Climate engineering might prevent that catastrophic change, buying us the time we need to get our greenhouse gas emissions down.

There are a few ideas out there that have a lot of research behind them. The most studied one is stratospheric aerosol geoengineering. Aerosols are microscopic droplets that are created in the atmosphere from chemical reactions. Some of these aerosols, like sulfur, are really bright and reflect sunlight back to space, cooling the planet - we know this because large volcanic eruptions do it.

People have talked about the idea of putting sulfur in the upper atmosphere on purpose, maybe by flying the sulfur up in airplanes.

Another idea is marine cloud brightening. There are certain types of low clouds over the ocean that, under the right conditions, may get brighter if one were to spray sea salt aerosols into them.

A third idea that has been looked at is cirrus cloud thinning. Cirrus clouds trap heat, preventing it from leaving to space - this has a warming effect on the planet. If we could thin those cirrus clouds, then more heat could escape to space.

<strong>Wispy cirrus clouds</strong> like this trap heat. If we could thin these clouds, we could possibly buy ourselves more time to lower our emissions.

All of these ideas that have been proposed (and others) are only temporary means of addressing climate change. If climate engineering is all we do, and we don't curb our greenhouse gas emissions, we have to keep doing climate engineering in increasing amounts forever.

That's not a sustainable solution to climate change.

And also, if climate engineering were to suddenly stop, there would be a catastrophic rebound warming, far faster and far worse than the gradual increases in temperature we're experiencing from climate change. That's why climate engineering can't be the only thing we do, if we do it at all.

Geoengineering techniques to fight climate change have never been implemented in the real world. Can you talk about how modeling helps you explore this area of study? What role does supercomputing play?

Supercomputing plays an enormous role in our understanding of climate engineering. You're right that these geoengineering techniques have never been implemented in the real world, and for good reason.

<strong>Supercomputers like Big Red 200</strong> allow us to simulate climate engineering experiments. We can't test these theories in the real world without major consequences, and HPC machines like this are crucial. Courtesy Emily Sterneman, Indiana University

There are certain processes that could be tested by field experiments, like how do these aerosols form and disperse in the upper atmosphere. But we can't design a field experiment to test the climate effects - because the climate system is so noisy, the field experiment would have to do so much climate engineering that it would basically look the same as deployment.

That's not a good way to test this idea, because we only have one planet, and we live here, so we don't want to risk messing it up just to see what would happen.

Climate models allow us to take our best understanding of the way the climate system works and simulate it in computers. With these climate models, we can inject sulfur into the upper atmosphere or brighten low clouds and see what the climate effects might be without risking any of the unknown side effects that might show up in a real-world deployment.

These climate models run on supercomputers, which are an essential part of our toolkit in understanding climate engineering.

During our last conversation, you said: “The first time I heard about geoengineering I thought, ‘This is crazy – who wants to do this?'” Obviously, the more you learned the more interested you became. Is the climate crisis really so bad that geoengineering is a reasonable possibility that we need to consider?

I think we need to consider everything, even if we never end up doing some of it.

<strong>World leaders</strong> and the constituents they represent will be the ones deciding on climate change, not scientists like Kravitz. His job is to make the rest of us as informed as possible.

Climate engineering is scary, but so is climate change. Climate engineering has the potential to save a lot of lives, and it also has potential for side effects. At some point, decision makers are going to figure out whether climate engineering is something that we as a society want to do, and if so, what it's going to accomplish.

My goal as a scientist is to give them the best information possible so that they can make an informed decision.

Is it too late to save organized human life on planet Earth?

That's a really hard question, and I'm afraid it's out of my area! Organized human life depends on so much more than climate science - ecosystems, agriculture, geopolitics, and ethics just to name a few.

I will say that whenever I go to conferences or interact with colleagues, I see a lot of really smart people who care about the problem of climate change and want to do something about it. That gives me hope.

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