Many climate predictions focus on specifically 100 years in the future. What about 200 years from now? Or 1000 years, or 20,000 years?
Part of the answer, I think, is that prediction becomes more and more problematic as it tries to look farther and farther ahead, but it would still be interesting to know what scientists guess. A page like this one leaves one confused about when the next major glaciation is expected. Is it possible that positive feedbacks associated with warming will return the Earth to the warmer climate it had before the Pleistocene Epoch?
Long term predictions are problematic because they would involve a lot of theorizing about the direction society will take. There is very little hard data to go on in terms of what society will be like in 1000 years - or what technology will exist. ie will we have fusion power? Or will we be still burning the entire planet’s store of coal while folks are still denying climate change?
The predictions would therefore be reduced to mere guesses, with very little predictive power.
Man, you giantists are always trying to stir up a panic. Haven’t you figured out, yet, that it’s all a big scam? It’s just those damn astrophysicists trying to get more grant money.
Current reserves of fossil fuels will be long gone 1,000 years from now (and I doubt we will come across any massive unknown reserves); conventional oil production is increasingly regarded as at or near its peak (though there is a lot in the tar sands and oil shales, but it is also much harder and energy intensive to extract them).
Assuming most fossil fuels are burned, I am guessing that a PETM-like episode of warming would occur, after which it would gradually cool, eventually returning to Pleistocene-like conditions. That is mainly based on current plate tectonics, since I don’t think there is any carbonate-rich ocean crust being subducted at the moment (the long term cooling since about 50 million years ago started when India collided with Asia and the carbonate-rich ocean crust was consumed, along with increased weathering from the Himalayas, resulting in declining CO2 levels).
Of course, in the very long term, the Sun will gradually get warmer, as part of a continuous process at the rate of 1% per 100 million years (until it goes red giant); this will make Earth uninhabitable in as little as 1 billion years, and possibly sooner since increased solar radiation will cause faster weathering of CO2 until CO2 levels get too low to sustain plant life, below about 10 ppm depending on the photosynthetic process; even the addition of CO2 from fossil fuels (and even if no new fossil fuel deposits are created) won’t have much impact on these timescales since it is being bound up in rock and is only returned by volcanism, which will also gradually decline as the core cools down.
Petition to have the planet moved to a further orbit in the next billion years. Also, you might want to make sure no one is planning a hyperspace bypass…
This long term decline in the Earth’s environment (first the loss of CO2 leading to cooling and plant death, then the heating caused by the brightening Sun) would mean that our planet would need to be terraformed in order to support life.
Not enough CO2 to support a biosphere? Add some artificially, either by processing the crust or by importing it (Venus has got far too much). In fact scooping CO2 out of Venus’ atmosphere could be acheived using solar powered scoopships, which could then spiral out to bring their cargo to Earth. Our planet could be habitable right up until the Sun gets too bright.
And don’t give up on the planet after that; a sunshade between Earth and the Sun could cool our world until the star finally leaves the Main Sequence, at which point it would probably be a good idea to write the old planet off.