Our solar system orbits the black hole at the center of the Milky Way galaxy with a period of 225Ma-250Ma, the Galactic Year or the Cosmic Year. This means that approximately one Galactic year ago, the Permian-Triassic Extinction event or the “Great Dying” occurred on Earth, with about 90% of all species going extinct. We are entering the first galactic anniversary of the P-T extinction event, the Great Dying, as far as the solar system is concerned.
Our sun is also a G-type main sequence star (G2V) and assuming that it didn't exhibit strange anomalies during its evolution, it would have had a fairly predictable increase in intensity as its hydrogen molecules get converted to helium in the nuclear fusion reactions in its core. Since birth, the luminosity of the sun would have increased by about 40% and over the past 500 million years during which complex life evolved, the luminosity of the sun would have increased by about 5%. While a luminosity increase of just 5% may seem like a minor change, it actually has major implications for the sensitivity of the Earth to greenhouse gas perturbations. Greenhouse gases are like the blankets that the Earth wears to ensure optimal conditions for Life and as the sun gets hotter, the Earth would need to shed some of those blankets.
When the solar system was born 4.6 billion years ago, planet Earth was perfectly situated near the center of the Habitable Zone (HZ) around the Sun. The HZ is the zone where liquid water would be available on the surface of the planet, which is essential for life to flourish on the planet. The boundaries of the HZ are typically calculated using 1-dimensional, cloud-free climate models as pioneered by Kasting et al. The inner edge of the HZ is calculated for the loss of liquid water on the surface and the outer edge of the HZ is calculated using the maximum greenhouse effect. Using this model, it can be shown that the HZ around our sun, at present, is 0.95AU to 1.67AU, where AU is the Astronomical Unit, the average distance of the Earth from the Sun. In this model, the Earth is presently 0.05AU away from the inner edge of the Habitable Zone around the sun.
Recently, an updated 1-Dimensional, radiative-convective, cloud free climate model, with updated H2O and CO2 absorption coefficients was used by Dr. Ravi Kopparapu and others at Penn State University to show that the HZ limits of our solar system is from 0.99AU to 1.70AU. This would mean that the Earth is extremely close to the inner edge of the Habitable Zone and therefore, very sensitive to perturbations in the greenhouse gas composition in the atmosphere. According to best estimates, the CO2 concentration in the Earth's atmosphere 500 million years ago when complex life first formed on Earth was between 4000ppm to 20,000ppm. In that atmospheric environment, a 2000ppm increase in CO2 concentration would, at most, be a 50% increase, a similar percentage increase to the one that we've caused in the Earth's atmosphere since pre-industrial times. However, the same 2000ppm increase in CO2 concentration from pre-industrial levels would be like a 700% increase and most likely fatal to Life on Earth today. This is because the CO2 concentration in the pre-industrial atmosphere was a relatively minuscule 280ppm.
In such an extremely sensitive atmospheric environment, at the very inner edge of the Habitable Zone around the Sun, the Earth spawned a superlative, tool-building species that has the capacity to quickly reverse any major perturbations in the atmospheric composition through technological interventions. Knowing that the chemical feedback mechanisms were too slow to prevent catastrophic consequences to all Life at this inner edge of the Habitable Zone around the sun, the Earth fashioned some fast feedback mechanisms through Life - to defend Life. In order to ensure that our species fulfills the caregiver role in the ecosystem, the Earth birthed our species with the core Dharma of compassion for all creation. Further, to ensure that the species develops the necessary technology first to fulfill its sentinel role, the Earth spawned the species in an environment of abject terror so that the species overcomes its core Dharma and spends 200,000 years fashioning increasingly sophisticated weapons and technologies to overcome that terror. In the process, the species creates an atmospheric perturbation similar to, though not as severe as that which would be encountered with sustained volcanic eruptions or through an asteroid impact in the ocean. In that sense, what we're about to embark upon in the next few decades is a trial run for the real long-term tasks that we've been spawned to do.
The Earth had to force us to go through all that violence and suffering of the past 200,000 years for there is no way that a human society full of compassionate, enlightened "Buddhas" would have ever been motivated to develop sophisticated weapons technologies and constantly seek to improve those technologies. It is only fratricidal, intra-species warfare that could have compelled us to develop these technologies. It is only natural that when we are in a system that has normalized war, the act of killing other human beings, we would consider it normal to destroy forests and the ocean and kill other species. But it is mostly the same sophisticated technologies that are now being deployed to monitor the Earth’s biogeophysical and biogeochemical processes. In the future, it is these same technologies that will be deployed to defend all Life on Earth from both internal and external threats.
Thus Mother Earth, or if you will, God, Yahweh, Allah, Brahman, the Creator, the Great Spirit, Higher Consciousness, or just plain Life, that beautiful process which seemingly creates order out of chaos, with infinite compassion for all Life, spawned a species that can control the Earth's CO2 thermostat more finely, deter the collisions of asteroids and comets, and protect Life against any existential threats, external and internal, even as the Sun inexorably gets brighter over time and as the solar system enters the first galactic anniversary of the Great Dying. Who knows, in another 500 million years, when the Sun is 5% brighter than today, the evolutionary descendants of our species will deploy technologies to reflect all that excess energy from the Sun back into space and allow life to continue on Earth, well beyond the inner edge of the Habitable Zone.
The possibilities are endless, when our technological prowess is marshaled in the service of Life. As Father Pierre Tielhard de Chardin predicted nearly a century ago,
"The day will come when, after harnessing space, the winds, the tides, gravitation, we shall harness for God the energies of love. And, on that day, for the second time in the history of the world, man will have discovered Fire."
But in our story, we have always been harnessing "for God the energies of love," for we have always been building our tools and technologies for a larger purpose. We unknowingly stabilized the Earth’s climate during the first 10,000 years of the Holocene era, mainly through deforestation and desertification. But over the past 200 years, we developed all the technologies we need to consciously maintain that climactic stability for the foreseeable future, without having to depend on further deforestation and desertification. In the process, we have caused the Earth to suffer a mild fever, but we know that this fever will subside once we help regenerate forests on half the Earth’s land surface and we transition from fossil fuels to clean energy sources.
Besides, an Earth with a stable climate maintained by a compassionate human presence, is an Earth that no longer has to undergo the periodic glaciations and deglaciations that occurred over the past 3 million years due to the Milankovitch cycles. Every such climactic gyration caused untold suffering to species that had to migrate and compete for habitat. Therefore, in the final analysis, the temporary suffering that humans and other species had to endure as we developed our tools and technologies, will turn out to be minor compared to the suffering that is avoided with our compassionate, technological presence.
Therefore, we are no different from the elephants of SAI sanctuary that so effortlessly and routinely contribute to the good of the planet's biosphere. We are no different from the forests that regulate rainfall, or the ants that sequester CO2. We are the thermostat species, the sentinel caregivers (Khalifahs) of the Earth!
In that affirmation of a plausible evolutionary purpose grounded in science, just as envisioned in the world’s religious scriptures, we will indeed be rediscovering Fire for the second time!
 Kasting et al, “Habitable Zones Around Main Sequence Stars,” ICARUS 101, 108-128, 1993. http://bit.ly/1TpFbat
 Kopparapu, R, et al, “Habitable Zones Around Main-Sequence Stars: New Estimates,” Earth and Planetary Astrophysics, 2013, Doi: 10.1088/0004-637X/765/2/131, http://arxiv.org/abs/1301.6674