Watch: 100 Million Years of Simulated Evolution Shows Earth's Drastic Changes

Earth’s landscape has always been in flux. But most large-scale changes take far longer to manifest than we’ll ever witness in our lifetimes.

Hundreds of millions of years had to pass for the continents to split apart, creating the seven land masses we know today. Earth’s mountain ranges didn’t appear overnight, but rose gradually after the collision of tectonic plates. And many of the enduring rivers we’re familiar with now were formed through the tedious, steady process of erosion.

A new computer model described this week in the journal Science offers a detailed view of how much the surface of our planet has morphed over the past 100 million years. Employing data from past and present observations of the planet’s geology and landscapes, researchers present an exploration of the natural processes that carved Earth’s surface over time.

They also write that the model could be a valuable tool for other scientists to predict how our planet will continue to evolve, especially in the face of climate change.

Ever-shifting Earth

Roughly three years ago, researchers at the University of Sydney in Australia began a huge undertaking: creating a model that could simulate millions of years of landscape changes across the entire globe.

Since the 1990s, they write, software has been developed to simulate the erosion and movement of sediment, which is one of the major factors that shapes features on the Earth’s surface. But there wasn’t yet a model that could simulate sediment changes in concert with other processes happening on Earth.

“If you look for a continuous model of the interplay between river basins, global-scale erosion and sediment deposition at high resolution for the past 100 million years, it just doesn’t exist,” Tristan Salles, a lecturer at the School of Geosciences at the University of Sydney and author of the new study, said in a press release.

So Salles and colleagues created the Global Scalable Paleo Landscape Evolution model (goSPL for short). It incorporates dynamics from the atmosphere, hydrosphere (all of Earth’s water), tectonic plates, and the planet’s mantle. The researchers say it is the first model of its kind.

Chronicling changes

For the new study, goSPL was combined with models of past global climates and reconstructions of historical plate tectonics. Then, several hundred computer processors were employed to run simulations of the Earth’s changes over the past 100 million years.

Because it covers such a long period of time, the model is broken into intervals of a million years. With each leap of time, the continents shift slightly, oceans expand, mountains begin to evolve, and waterways appear or disappear across the land.

The model allows users to zoom into as small as a 10-kilometer (6.2-mile) area, offering a high-resolution view of every part of the Earth.

Modeling the interplay of the many different dynamics that shaped Earth’s surface can give researchers insight into how today’s landscapes formed. But it could aid in other ways, too.

“It’s not only a tool to help us investigate the past but will help scientists understand and predict the future, as well,” Salles said in a press release.

Future predictions

One of the biggest factors shaping the Earth today is human-caused climate change. We know, for example, that greenhouse gasses are causing excess warming in the atmosphere, that glaciers are melting at unprecedented rates, and sea levels are gradually rising.

But there’s still a lot we don’t know about the effects of climate change on Earth’s future. Not every region will experience the same outcomes, thanks to the complicated nature of many different systems working together to shape environments.

Looking into the past, though, could shed light on the future. As the model clearly shows, Earth has gone through many changes in its climate and landscapes for the past 100 million years.

“The geologic record is rich with examples of ‘alternative Earth’ states in which extreme conditions and environmental change are recorded,” writes Todd Ehlers, a professor in the department of Geosciences at the University of Tübingen in a related commentary about the new model.

“Understanding how past topography and sedimentary by-products changed through time is one important piece of the puzzle for understanding future Earth system responses, such as climate change,” Ehlers writes.

And having a better understanding of how different systems work together could inform future predictions of changes, as well. Salles notes that the flow of sediment from land into oceans has altered their chemistry over time — just one example of how a slow process can transform landscapes.

“Given that ocean chemistry is changing rapidly due to human-induced climate change, having a more complete picture can assist our understanding of marine environments,” he said.