text: climate changeeartherecosystemsland-use
  An aerial shot north of Miami showing islands filled with houses, apartments, and other buildings. (Photo: Daniel Slim/AFP, Getty Images)
  To quantify these ecological changes, the researchers examined hundreds of years of fossil records from the global Neotoma Paleoecology Database. By looking at shifts in fossilised pollen records gleaned from records of sediment cores, they were able to determine what types of vegetation lived in different locations across North America at different times. In particular, they looked for signs of abrupt, system-wide transitions, such as when a grassland becomes a forest, or when an oak forest sprouts up where a spruce forest once was.
  The scientists can't yet pinpoint what exact human activity drove each of those rapid shifts, but much previous research indicated that agriculture, pollution, logging, fishing, and extracting fossil fuels have all played a role. The climate crisis — driven by some of those very activities — is also a likely culprit. Regardless of which activity is mostly to blame for specific shifts, the new findings as a whole suggest human actions changed North American ecosystems more than the last Ice Age.
  This authors findings are, to say the least, troubling, especially because we're not done making changes yet. We — or usually, those of us with power — are continuing to exploit the natural world, burning down trees, extracting fossil fuels, and clearing more and more land for farming. Studies show that many more of these abrupt shifts could be on the way unless we makes big changes. We could lose rainforests, coral reefs, and wetlands. That's not just a problem for the wildlife and unique flora that live there.