We think of climate change in terms of hot and cold (mostly hot). In fact, temperature is just one way to measure the effects of climate change. Daniel Grossman is a science journalist who spent much of the last decade reporting on how scientists study climate change. Grossman’s new enhanced e-book app is Deep Water: As polar ice melts, scientists debate how high our oceans will rise. Based in part on his trip to Australia with an expedition led by Maureen Raymo of Columbia University’s Lamont-Doherty Earth Observatory, Grossman shows how scientists are looking to the past to see our future.
LN. How many places did you go in researching this book?
DG. The book is mostly about an expedition I joined in Australia. We traveled all across the continent and partway up the western coast. That was the only place I went specifically for the book, but the book brings together a lot of the reporting that I’ve done over the years. For instance I talk about Illulissat, a town about a third of the way up the western coast of Greenland, where something called the Jacobshavn glacier off the Greenland ice sheet empties into the ocean. I spent a year in Boulder, Colorado, one of the leading places in the world for climate change research.
LN. Why did you go to Australia?
DG. The research I focus on in my book app has to do with how high the sea rose during the Pliocene, about three million years ago. As you can imagine with all the geologic changes that have occurred over the last 3 million years, you can’t go to just anywhere to find this evidence. You only get preservation of the geological record, coral or fossils of shells, in certain places. The researchers chose Australia because it has certain characteristics [it’s dry, and does not sit on or near the boundaries where tectonic plates come together] that they thought would make it more likely they could find a Pliocene beach.
LN. Why the Pliocene?
DG. The last time carbon dioxide levels were as high as today was during the Pliocene. Carbon dioxide levels went down for 3 million years and then it went up the same amount in 150 years. To understand what our future might bring, we look back to the last period where we had levels like that.
It’s not like we’re immediately going to be like the Pliocene because there’s a lag between certain parameters and other parameters. When you have a higher carbon dioxide level you don’t immediately get the temperature called for by that carbon dioxide level.
And once the temperature reaches a certain level the effects will take time. Then we’re going to have Pliocene level ice sheets. But it’ll take time and we don’t know how long that lag will be.
LN. Are they’re trying to figure that out by going to these places?
DG. The ultimate goal of this team is to figure out how big these ice sheets were during the Pliocene. What [Columbia University researcher] Maureen Raymo and the rest of her team is interested in is what earth’s ice sheets might do in the future as carbon dioxide goes up and as temperature goes up. One way to think about that is to look at what the ice sheets were like during the Pliocene.
There are many ways to go about doing that. One way is to go and look at the ice sheets; and people do this, they take ice cores, they look at the sediments right outside the ices sheets and try to figure out how big the ice sheets were. Now, these guys are doing something quite different. They’re looking at shorelines and they’re hoping that will tell them what the ice sheets were doing back then.
LN. What’s your takeaway?
DG. There’s no question that the earth is going to get many degrees warmer in the next 100 years [Editor's note: see Grossman's comment in the Comments section]. That’s just irrefutable. Even if we completely stop burning fossil fuel, there’s a certain amount of warming that we’re going to face anyway, just based on the fact that there’s a time lag between carbon dioxide levels and actual temperature. That will have many, many effects, some of which haven’t even been imagined yet.
We’ve noticed all sorts of things we hadn’t anticipated—animals changing their migration patterns. One of the takeaways of my reporting is that there are going to be big changes and we don’t even know what all of those big changes are.
We have optimized ourselves for certain conditions. And although we may be able to change how we live and what kind of structures we build to meet at least some of the future conditions, we’re not ready to do that. Those could involve massive expenses.
LN. So are you going to move to Australia?
DG. People quite glibly tend to talk about climate change having winners and losers. I think it will, but it’s not going to be as simple as people think.
It’s expected that ecosystems are going to be moving north. If the temperature was just right for you here in Boston, just right for sugar maples and maple syrup, then in 10 years or 50 years you’d expect that that ecosystem would’ve moved a little bit north up to New Hampshire, towards Canada.
But you don’t just have an ecosystem pick up and move. Trees can’t move very fast. Birds can move very fast, but birds may try to move north and find the trees with the insects they like aren’t there. The trees will eventually move, but by the time they get there the birds they rely on, for pollination or killing off insects, will be wiped out, because they got there too early. So all the ecosystems will come apart. It’s hard to know which parts of the world will be best to live in and over what time scale they’ll change.