Photo credit: The Adler Planetarium
We are all living in a giant science experiment — an experiment with no control group, which has never been performed before, and will never be performed again in exactly the same way. Our “planetary experiment” is taking place right here, every day, on Earth, and we have the ability to affect its outcome. In fact, part of that outcome has already been determined by those who have come before us, and we hold in our hands the power to impact the future of generations of humans that will be born after us, whom we will never meet.
It’s a humbling thought, and one that sits at the center of today’s climate change policy. Such a thought requires some serious consideration. And there’s no escaping it — this planetary experiment is our project, and our responsibility.
This is the heart of the lecture delivered by Dr. Daniel P. Schrag on May 9 as the latest installment in the Adler Planetarium’s Kavli Fulldome Lecture Series. The series, which focuses on questions of planetary and space science, includes top-notch talks by experts in these fields, set against stunning, immersive graphics that illustrate the speaker’s points in engaging and easy-to-understand ways. Kavli Fulldome lectures are presented live in The Adler Planetarium’s Grainger Sky Theater, where audiences are pulled directly into the subject matter through high-quality graphics, simulations, and photography. Rather than simply sit and listen to the lecture, you will experience it up close and in person. This is not your typical science lecture!
This month’s event was broadcast live online and in several partner planetariums around the world simultaneously. But if you missed it, don’t worry — you can still find this amazing lecture online on the Adler’s YouTube channel, available to watch anytime with 360-degree viewing for an engaging experience with any computer or virtual reality headset, including Google Cardboard.
The concentration of carbon dioxide in Earth's atmosphere has risen dramatically since the industrial revolution to unprecedented levels. // Photo credit: NASA; National Oceanic and Atmospheric Administration //
Larger imageDiving deeper into the experiment
I had the opportunity to attend the lecture in person — my first Kavli Fulldome Lecture, but I am hoping it won’t be my last. As a former student and researcher in the fields of planetary science and geosystems, I was particularly interested in the subject matter of the presentation.
Dr. Schrag is unarguably an expert in the field of climate science and policy. He currently holds the positions of Sturgis Hooper Professor of Geology, Professor of Environmental Science and Engineering at Harvard University, as well as director of the Harvard University Center for the Environment. He also serves as co-director of the Program on Science, Technology, and Public Policy at the Harvard Kennedy School. Dr. Schrag’s past work includes a position on President Obama’s Council of Advisors on Science and Technology (PCAST) from 2009 through 2017, where he contributed to reports on energy technology, national energy policy, climate change, agricultural preparedness, and STEM education.
Schrag has studied climate change over Earth’s history, not just the past several decades. His lecture highlighted long-term trends in climate and atmospheric carbon dioxide concentrations, focusing in on both the manmade and natural mechanisms of climate change and how they affect both the planet itself and the organisms living on it. Earth, he stressed, has gone through massive temperature swings in the past. In fact, Schrag was part in the development of the “Snowball Earths” hypothesis, which outlines how several periods of extreme glaciations have affected our planet in the past.
But the focus of Schrag’s lecture was not only on the past — it was also on the future, on the fact that Earth is now undergoing changes due to the unprecedented increase in carbon dioxide in our atmosphere as a result of human activity. Throughout the lecture, the graphics invited us to “put on carbon dioxide glasses” and see the invisible, allowing us to envision the increasing concentrations of this greenhouse gas around our planet and how it will affect the climate for centuries to come.
Our planetary experiment, Schrag stressed, has already been set in motion. Even if fossil fuel consumption was to stop completely within the next 200 years, Earth’s fate has already been decided for millennia to come.
The good news? Earth will be fine. The planet’s climate will bounce back, likely in a few hundred thousand years — relatively nothing to worry about on geologic timescales. But the bad news? Life on Earth has never before had to adjust to such rapid changes in climate and environment, and whether or not it will be able to evolve quickly remains unknown — or, in some cases, such as the coral reefs, seems unlikely.
Ultimately, the driving factor behind Schrag’s lecture and the key point to take home is this: “The decisions we’re making today in terms of what energy we use have implications, not just for our children or grandchildren, but the carbon dioxide we’re putting in the air today is going to be there for tens of thousands of years,” he said, as the talk drew to a close. “I don’t even know how to think about that from any kind of political or ethical perspective. We don’t think about those timescales. Even as a geologist, I don’t think about the implications of my behavior for 20,000 years.
“But that’s the experiment we’re doing.”
Our Earth and other Earths
After the lecture, I had the opportunity to speak with Dr. Schrag. One of the topics we discussed was the field of exoplanet research. Not only is the discovery and study of exoplanets one of the hottest new fields in astronomy, but perhaps learning more about Earth-like planets around other stars and their unique conditions, their own “experiments,” might help us better understand our own, or vice versa. This is why, even if you’re here only for the astronomy, it’s important to understand and support research into our own planet’s past, present, and future climate and the factors that affect it.
Kepler-22b, a planet orbiting in the habitable zone of a Sun-like star. // Photo credit: NASA/Ames/JPL-Caltech
“It’s really important for people who are beginning to think about the climate of exoplanets … to actually understand the Earth’s system as well as they can,” Schrag says. “It’s not that exoplanets can’t be very, very different, but ultimately the tests of the complex geochemical cycles we’re going to see in other planets do rest on our own understand of Earth’s history.”
It’s a straightforward concept that makes a lot of sense — putting the resources into understanding our home will help us better understand the slew of exoplanets we’ve already found, as well as the countless others not yet on our radar. Plus, it’s easy to study our planet, compared with those that are currently difficult to directly image and characterize.
In some ways, Schrag says, thinking about the Snowball Earth or the evolution of atmospheric oxygen on Earth is like thinking about a different planet. “The Earth was a different planet four billion years ago,” he says. “To me, the Earth is more unusual than I think most people appreciate. Many astronomers thought that as soon as we started seeing other planets, we’d see things just like the Earth. And the answer is, ‘just like the Earth’ is still not just like the Earth today. Even in Earth’s history, this is a special place.”
To that end, Schrag stresses how it actually took things like the Snowball Earth to create conditions like the modern oxidation state of our planet and generate a home where we can live. While he thinks it’s unlikely astronomers will find something “just like Earth” as it is today, “It’s exiting. We’re on the cusp of discovery, and like any field, new data will change our minds.”
He estimates that within 10 years, astronomers will have geochemical information about other planets. When that happens, he says, “a collaboration between geochemists and climate scientists with planetary scientists is going to be essential.”
Closer to home, we also discussed briefly the idea that intentionally injecting reflective particles into Earth’s atmosphere could slow down the current warming trends. He spoke about this point at the end of his lecture, because as the climate continues to change — which it will — it may become necessary to physically offset these changes to maintain a home where humans and the organisms we need to survive can live.
“We know enough to know that we should be doing something more than we’re doing,” he says. But before we “do something,” we need to spend a lot more effort understanding what that something is, “including understanding everything that could go wrong.
“Ten years ago, everybody was talking about this, we were focused on sulfate aerosols, because that’s what volcanoes do,” he says. “They send sulfur into the stratosphere and that can have a cooling effect. What we know now is, that is likely to disrupt the stratospheric ozone that shields us from UV radiation. So now there are other ideas — but that’s the importance of research. Had we not done the research on this, we wouldn’t have known. And then maybe someone would have done this and it would have been catastrophic.”
In the end, our home and the conditions in which we live are in our hands. Climate change is real, and it’s going to become increasingly important in our lives as time marches forward. The solution now, Schrag says, is to ensure that policymakers and those with the power and drive to make changes “have the best information available.” As scientists and science enthusiasts, “that’s our obligation.”
You can check out the entire lecture online, and stay tuned to the Adler Planetarium’s website to learn about future Kavli Fulldome Lectures.