Ask an astronomer! Should we block out the sun to stop climate change?

Michelle Thaller from NASA examines if it's possible to put up a giant disk to block out the sun's rays and cool Earth.

Lisa, I share your concern about climate change. This is something that’s one of the biggest challenges that humanity has ever faced, and it’s something that in the next couple of decades and centuries we’re going to have to really band together and work together to solve.

And when you ask a question like you did, about “how might you solve climate change,” it actually gives me a lot of hope because it means that young people like you are really starting to think about ideas about how we could address climate change.

You said, “could you build a giant disk and put it between the earth and the sun and have it act as a kind of sunshade actually cooling down the earth?” That’s a wonderful idea. There are some things about that that would be quite difficult and one thing is that the sun is actually very large, it’s much larger than the earth, so it actually projects light around anything that you put up there.

You’d have to put a very, very large disk up there. It might have to be something roughly the size of the planet in order to shade the planet effectively against the sun. So that’s something that might be possible, but it would be very expensive and difficult to construct. But I love the fact that you’re thinking about it.

It does however to me sort of not address the underlying problems with climate change. A lot of people have ideas similar to yours that, what if we could just block out some of the sun’s light, would that actually make climate change go away? And one of the ideas people have is possibly launching lots and lots of particles of dust up into the atmosphere.

We observed that when there’s a volcanic explosion and the earth naturally puts lots and lots of dust up into the atmosphere, the earth’s climate cools. We observed this in the ‘90s when Mount Pinatubo erupted and we actually had a decline, a little bit of a notch on the global warming, just due to this volcano putting lots and lots of stuff up into the atmosphere.

So could we do that artificially could we just darken our atmosphere to actually have less sunlight get through? The answer is yes, we probably could, but it would be a huge effort.

A single volcano puts up many, many thousands of tons of dust up there, so this would have to be something continuous: lots and lots of rockets or aircraft distributing dust across the atmosphere. And the thing that kind of frightens me is that we really don't understand our atmosphere enough to know what that sort of cooling would do. The atmosphere stores heat, it creates winds and of course the air moves around, there are storms; scientists spend a lot of time studying how the atmosphere stores heat, how the weather forms, and when you darken the atmosphere I’m not sure what it would do to our weather. It would be a very dangerous experiment to do if you couldn’t control it.

And the same thing with building a disk: I’m not sure that darkening the earth is a very good idea; it may change things like weather patterns or even ocean currents, the winds, all of that. It also doesn’t get at the problem of carbon dioxide.

Now the reason our atmosphere is getting warmer and warmer and warmer is because we humans are putting lots of carbon dioxide up into the atmosphere and this acts as what we call a greenhouse gas. Sunlight can get through the atmosphere but the carbon dioxide traps it and it can’t release itself back into space so it gets warmer and warmer over time. Carbon dioxide doesn’t just warm the atmosphere, it also affects our oceans. When ocean water combines with carbon dioxide it creates something called carbonic acid and it makes the oceans more and more acidic over time and this is a really big problem for marine life. There are things like algae, the algae in the oceans are responsible for most of the oxygen that we breathe, and the algae are having trouble forming because of the higher acid levels in the ocean.

So even if the one thing you solved was cooling the earth down, if we continue to put more and more carbon dioxide into our atmosphere there will be other serious repercussions. We could end up killing the ocean life system, for example.

So the problem really isn’t an external one, it’s not simply cooling the planet putting up lots of dust or building a wonderful shade like you suggest, the problem is really getting at our emissions of carbon dioxide and stopping those and stopping these dramatic changes that we see coming. Some of them are going to be very difficult to stop. I mean right now we’re observing the ice caps at both poles of the planet, in Antarctica and in the North Pole, melting very quickly. That won’t stop. Those ice caps will largely melt over many, many centuries and the ocean levels will rise in accordance.

I do think right now the challenge is how are we going to deal with the changes? We might not be able to change very many of them at this point, we need to band together as people make sure that we have ways to deal with refugees—people need to leave where they are because the oceans are rising. There’s going to be a lot of people that need homes, and there’s going to be a lot of support needed for the changes in agriculture, in fishing, in so many parts of our economy and our lives. There’s no easy solution. I do love that you’re thinking about it, and we need you to keep doing that.

Couldn't we just put up a giant disk to block out the sun's rays and cool Earth? Michelle Thaller from NASA answers if that's possible. She also wonders if any such solution is really looking at the underlying causes of climate change.

LinkedIn meets Tinder in this mindful networking app

Swipe right to make the connections that could change your career.

Getty Images
Sponsored
Swipe right. Match. Meet over coffee or set up a call.

No, we aren't talking about Tinder. Introducing Shapr, a free app that helps people with synergistic professional goals and skill sets easily meet and collaborate.

Keep reading Show less

Can the keto diet help treat depression? Here’s what the science says so far

A growing body of research shows promising signs that the keto diet might be able to improve mental health.

Public Domain
Mind & Brain
  • The keto diet is known to be an effective tool for weight loss, however its effects on mental health remain largely unclear.
  • Recent studies suggests that the keto diet might be an effective tool for treating depression, and clearing up so-called "brain fog," though scientists caution more research is necessary before it can be recommended as a treatment.
  • Any experiments with the keto diet are best done in conjunction with a doctor, considering some people face problems when transitioning to the low-carb diet.
Keep reading Show less

Steven Pinker's 13 rules for writing better

The Harvard psychologist loves reading authors' rules for writing. Here are his own.

NEW YORK, NY - JULY 21: Steven Pinker speaks onstage during OZY Fest 2018 at Rumsey Playfield, Central Park on July 21, 2018 in New York City. (Photo by Brad Barket/Getty Images for Ozy Media)
Personal Growth
  • Steven Pinker is many things: linguist, psychologist, optimist, Harvard professor, and author.
  • When it comes to writing, he's a student and a teacher.
  • Here's are his 13 rules for writing better, more simply, and more clearly.
Keep reading Show less

Want to age gracefully? A new study says live meaningfully

Thinking your life is worthwhile is correlated with a variety of positive outcomes.

YOSHIKAZU TSUNO/AFP/Getty Images
Surprising Science
  • A new study finds that adults who feel their lives are meaningful have better health and life outcomes.
  • Adults who felt their lives were worthwhile tended to be more social and had healthier habits.
  • The findings could be used to help improve the health of older adults.
Keep reading Show less