The environment will enter a new state, said Hadly. And we don't know exactly what that state will look like.
[...] There's the idea that, once you have more than 50 percent of wholesale disturbance in a given ecological system, major disturbance in the rest of the system will inevitably follow, said Hadly, who is also a senior fellow at the Stanford Woods Institute for the Environment.
[...] About 43 percent of Earth's land has already been converted to agricultural or urban use and, if current trends continue, is expected to reach the 50 percent mark by 2025. By 2060, using current trends, the number will be 70 percent.
By comparison, the last critical shift Earth underwent was the end of the last Ice Age. That famously dramatic example of climate change only involved ice melting from 30 percent of Earth's surface, and it resulted in a major transition in global climatic conditions and the distribution of life on the planet.
[...] Human population growth and increased resource consumption mean that anywhere from 20 to 40 percent of the planet's energy produced by living things now goes to support human society.
[...] Citizens of wealthy countries like the U.S. are less aware of catastrophic shifts in ecosystem services because we have the ability to cobble together short-term fixes that mask the global trend, said Hadly. But other countries aren't so buffered. In a world marked by water shortages and climate change, we simply aren't yet equipped with a flexible intergovernmental structure necessary to manage for this future.
Aucun commentaire:
Enregistrer un commentaire