The New Scheme
Researchers have developed a new classification system for planets, based on the reality of non-equilibrium thermodynamics. That sounds really complicated, but in simpler terms, the new schema takes account of the (possibly) negative effects a global species with industrial technology can have on the overall biosphere. The chemical composition of a planet and its average temperatures change when human-like species interfere with the biosphere.
The system is split into five different categories. Class-I planets have no atmosphere, rather like our Moon or Mercury, but a Class-V planet is profoundly affected by the presence of a post-industrial species that contributes entropy, or chaos, to the host planet.
Since we've begun studying how humans induced climate change, scientists have concluded that we are entering the Anthropocene epoch — the era defined by our profound impact on the environment. Earth is said to be transitioning from a Class IV to a Class V planet, going by the newly developed metric.
Keeping up with Kardashev
The Kardashev scale is a well-established method of classifying advanced civilizations based on the scale at which they have the capacity to harness energy (e.g., planetary, solar, interstellar, galactic, et al.). This new study describes it as the "gold standard" for ways of thinking about technologically advanced societies, but argues the case for a different type of scheme.
The original purpose of the Kardashev scale was to help SETI organize its attempts to find intelligent life. This new scheme instead sets out to understand the intertwined trajectories of the evolution of planets and their inhabitants. This information will hopefully help us learn what makes a civilization sustainable in the long-term.
The paper hypothesizes that the key is to "think like a planet." If civilizations don't consider their ecological impact on their home world, they're liable to thwart their own evolutionary progress.
The Bigger Picture
"The discovery of seven new exoplanets orbiting the relatively-close star TRAPPIST-1 forces us to rethink life on Earth," said Marina Alberti, one of the paper's authors, in a press release published by the University of Washington. "It opens the possibility to broaden our understanding of coupled system dynamics and lay the foundations to explore a path to long-term sustainability by entering into a cooperative ecological-evolutionary dynamic with the coupled planetary systems."
The study examines the relationship between technologically-advanced civilizations and their home worlds on the largest possible scale — but doing so might reveal harsh truths about the way humans treat Earth in the precarious here-and-now.
By looking at sustainability on a macro scale, we can see the greater consequences of a blasé approach to problems like climate change. Failing to treat our planet with the proper care could be the mistake of humanity's lifetime; a self-condemnation that denies our species the chance to evolve beyond its current form.