Earth formed about 4.6 billion years ago, some 9 billion years after the Big Bang. Life would appear on our planet a billion years later but would not emerge from the sea until 440 million years ago. Primates evolved about 60 million years ago and the first hominins appeared about 5 million years ago; finally, modern man graced the scene about 150,000 years ago.
While our species had a limited effect on natural ecosystems for most of our history, we began to significantly pollute the planet over the last few centuries. Fouling the air, water and soil, we have also altered the climate through our widespread use of fossil fuels. There is a reasonable probability that Earth may become uninhabitable within a few more centuries unless we make major strides in the areas of population control and pollution curtailment. Of course, supervolcanic eruptions, asteroid strikes and nuclear war could also play a role in our extinction.
Many humans envision that we will escape to other planets or other solar systems before our species is annihilated. More likely, it seems to me, we will fall victim to our lack of stewardship, perhaps aggravated by natural catastrophe, and, in our absence, nature will heal herself. Hundreds of millions of years later, assuming the sun has not yet begun to die, we may re-evolve from "lower species" that managed to survive the turmoil on Earth.
While our species had a limited effect on natural ecosystems for most of our history, we began to significantly pollute the planet over the last few centuries. Fouling the air, water and soil, we have also altered the climate through our widespread use of fossil fuels. There is a reasonable probability that Earth may become uninhabitable within a few more centuries unless we make major strides in the areas of population control and pollution curtailment. Of course, supervolcanic eruptions, asteroid strikes and nuclear war could also play a role in our extinction.
Many humans envision that we will escape to other planets or other solar systems before our species is annihilated. More likely, it seems to me, we will fall victim to our lack of stewardship, perhaps aggravated by natural catastrophe, and, in our absence, nature will heal herself. Hundreds of millions of years later, assuming the sun has not yet begun to die, we may re-evolve from "lower species" that managed to survive the turmoil on Earth.
