Did Climate Change Make Extraterrestrial Life Scarce?
David Waltham, physicist and author of "Lucky Planet", recently wrote an article for theconversation.com proposing his rather unique take on the increasingly mysterious Fermi Paradox, adding climate change to the growing list of possible solutions including the self-destructive nature of civilizations, the possibility that we are the first intelligent life in the galaxy, and the idea that we can't receive communication from other intelligent species.
Waltham believes that the principal factor that could explain why we haven't encountered extraterrestrial life in this galaxy, which is theoretically full of hundreds of millions of potentially habitable planets, involves the lack of life-supportive particularities on the vast majority of these planets as a result of climate change. He explains that since, "stars become brighter as they age, most planets with an initially life-friendly climate [may] become uninhabitable hot long before intelligent life emerges" thereby preventing the traces of life as we know it to form.
Waltham suggests that our planet might just have the precise conditions of life and geological movement that allows our Earth to defy the otherwise-standard trajectory of temperature to which other planets seem doomed. According to geological research on Earth's climate over the past 4 billion years, "biological and geological evolution have generally produced cooling and this has compensated for the warming effect of our aging sun." Although there have been times when the competing forces of the sun and the Earth's "geobiological cooling" have been unequal, causing the earth's temperature to rise or to fall, these forces have been able to provide the relative stability needed to sustain a constant supply of liquid water, since long before the beginnings of life on earth." With it's 4-billion-year-long stretch of "miraculously moderated climate change," Waltham nicknames our lucky little planet "a precious, fragile, jewel in space."
Although the search for extraterrestrials has generally been conducted under the hypothesis that Earth is not at all special, it could be that Earth is one of a few lucky worlds that have been able to develop and continue life as we know it.