
Yeah, probably not.
Via lib blog Raw Story:
Enrico Fermi, when asked about intelligent life on other planets, famously replied, “Where are they?” Any civilisation advanced enough to undertake interstellar travel would, he argued, in a brief period of cosmic time, populate its entire galaxy. Yet, we haven’t made any contact with such life. This has become the famous “Fermi Paradox”.
Various explanations for why we don’t see aliens have been proposed – perhaps interstellar travel is impossible or maybe civilisations are always self-destructive. But with every new discovery of a potentially habitable planet, the Fermi Paradox becomes increasingly mysterious. There could behundreds of millions of potentially habitable worlds in the Milky Way alone.
This impression is only reinforced by the recent discovery of a “Mega-Earth”, a rocky planet 17 times more massive than the Earth but with only a thin atmosphere. Previously, it was thought that worlds this large would hold onto an atmosphere so thick that their surfaces would experience uninhabitable temperatures and pressures. But if this isn’t true, there is a whole new category of potentially habitable real estate in the cosmos.
So why don’t we see advanced civilisations swarming across the universe? One problem may be climate change. It is not that advanced civilisations always destroy themselves by over-heating their biospheres (although that is a possibility). Instead, because stars become brighter as they age, most planets with an initially life-friendly climate will become uninhabitably hot long before intelligent life emerges.
The Earth has had 4 billion years of good weather despite our sun burning a lot more fuel than when Earth was formed. We can estimate the amount of warming this should have produced thanks to the scientific effort to predict the consequences of man-made greenhouse-gas emissions.
These models predict that our planet should warm by a few degrees centigrade for each percentage increase in heating at Earth’s surface. This is roughly the increased heating produced by carbon dioxide at the levels expected for the end of the 21st century. (Incidentally, that is where the IPCC prediction of global warming of around 3°C centigrade comes from.)
