“We estimate that Earth will cease to be habitable somewhere between 1.75 and 3.25 billion years from now.
“A fter this point, Earth will be in the ‘hot zone’ of the sun, with temperatures so high that the seas would evaporate. We would see a catastrophic and terminal extinction event for all life.
“Of course conditions for humans and other complex life will become impossible much sooner – and this is being accelerated by anthropogenic climate change.
“Humans would be in trouble with even a small increase in temperature, and near the end only microbes in niche environments would be able to endure the heat.”
Correct, the goldilocks zone will no longer apply to us. But with global warming going ahead full steam we can make the planet that way in a 100 years or so. I think i prefer the 1.7 billion number.