Earth is worth 3000 trillion.That value may be for the possibility that we are already here and earth has a hospitable environment. One wonders if this valuation is worth solely for its environment or the inhabitants.
Some of the planets are not worth much as they are far away from the humans and would be very costly to reach them with negative value for the human currency.Earth with its environment and life diversity has great economical value.As we pollute the waters and air including the fauna and flora value of the earth is decreasing.
If we do not pay much attention we may have a planet not as useful for human habitation and will increase the cost of habitation in it.
Areas away from equator are more expensive( in caloric needs) to live and reduce value of the planet.
If we increase the brain power of the inhabitants we will have a planet much higher valued than otherwise.I guess the valuation is based on Flora,fauna,water,land, atmosphere and the humans who can make decisions independent of all other factors to improve the well being of one species and may be many others.
How much the Human capacity alone is worth .With six billion population.If we can bring value to each human at one million dollars( in body parts they may be worth more in present market conditions) the race is worth six million billion that is six thousand thousand million.Oh that is six thousand trillion.
Finally it seems the scientist who calculated the value of earth at 3000 trillion was Short changing us .Humans alone can be worth double of that.If you added all the other stuff it becomes a complex matter and new questions arise?
What is the cost of exploitation of the resources of this planet.Is the value received from oil for transportation enough to offset losses to environment because of depletion of resources ,hydrocarbon release in the atmosphere and other impact on the species native to earth.