Consider what an increase of 4 °C over pre-industrial level means. In a December 31, 2013, article in The Guardian by Damian Carrington, Professor Steven Sherwood, at the University of New South Wales, in Australia, said "4C would likely be catastrophic rather than simply dangerous [ . . . ] For example, it would make life difficult, if not impossible, in much of the tropics, and would guarantee the eventual melting of the Greenland ice sheet and some of the Antarctic ice sheet."
If Greenland melts, it has been widely reported seas will rise "6 meters (20 feet)," and if the Antarctic Ice Sheet melts, "60 meters (197 feet)."
Below I wrote we need a modern Alan Turing (invented computer) with enough vision to matter. However, the more one looks into the scale and trends, the more obvious it is that social engineering is needed as much as technological geoengineering, especially since, as was noted below by Stefan Rahmstorf, Potsdam University Professor of Physics of the Oceans, speaking at the 2017 Bonn Climate Conference, geoengineering is unlikely to work. Many people cringe when they hear the term "social engineering" so how about "global social awakening"?
Robert Bly's book The Light Around the Body quotes Jacob Boehme (1575-1624): "For according to the outward man, we are in this world, and according to the inward man, we are in the inward world…. Since then we are generated out of both worlds, we speak in two languages, and we must be understood also by two languages." and
"Dear children, look in what a dungeon we are lying, in
what lodging we are, for we have been captured by the spirit
of the outward world; it is our life, for it nourishes and
brings us up, it rules in our marrow and bones, in our flesh
and blood, it has made our flesh earthly, and now death has us."
It is possible the IPCC is wrong, but probably not.
If you are a prayerful person, now would be good. I recall in Leonardo Dicaprio's Before the Flood, he met with my favorite Pope, Francis. Dicaprio noted "He said that as far as the Paris Conference is concerned, he felt was a step in the right direction, but certainly not enough. He feels we all need to keep speaking out about this issue as loud as we can, and that we must immediately take action. But more than anything, he said to pray for the human race."
If space aliens are watching, children of the same God, I hope they don't follow a Star Trek-like "Prime Directive" or "Temporal Prime Directive."
If they are following those, or aren't watching, it's up to you, me, and anyone willing to help.