I loved this piece. The idea behind it is new and refreshing. I would suggest you try and make smaller paragraphs. Readers tend to get lost in trying to figure out where they need to read next.

***(new paragraph) Jack ran quickly down the hillside and caught up with Deb. (NOT a new paragraph) "Why are you in such a hurry to get home, it is the weekend?"
***"You know it is Brad Field's funeral today, (period not a comma, caps on -I) it is being televised at 3 p.m."
***"Oh, I forgot, (period not a comma; caps on -Y) yes we should not miss that, (period not a comma; caps on -G) guess neither of us would have jobs and none of this would exist without him." He waved a hand at the green landscape as he spoke.
***"Exactly," said Deb, "So chop chop let us move", doubling her pace. (Rewrite: “Exactly. So chop chop let us move,” said Deb as she doubled her pace.)
*** (new paragraph)They got to the terminus, at the foot of their giant apartment block, just 5 minutes later, and disembarked, taking the lifts to the 212th floor, to their apartment.
***They rushed into the Living Room, shouting to the Home AI as they did, to turn on the 3D viewer and tune into the funeral. They got pictures of the grand cathedral in Sydney, where the funeral was taking place, (period not a comma, caps on -T) and the commentator was speaking about Brad's life, as they waited for the coffin to arrive, (period not a comma, caps on -M) millions of people lining (-ed not -ing) the streets, with Australian flags in their hands, waiting for the convoy to appear.
***(new paragraph, add opening quotes) “A lake, that previously filled only 4 (normally any number below ten is spelt out, so you might want to put the word “four” here) times a century naturally, became the major inland freshwater sea we all know and love today.
***(new paragraph, add opening quote marks because the announcer is still talking) “As forests and farms replaced deserts Australia started sucking in the CO2, that had been warming up the world for a generation and reversed the greenhouse effect.
***(new paragraph, add opening quote marks) “There has perhaps been no man in all history who was so mocked in the early stages of his life and yet who is so praised, as he is today.
***"Oh look into the sky," said Debs, (no -s) "Oh that is marvelous."
***(new paragraph) It was an amazing unbroken story of success and expansion coupled with clean air, clean energy, an explosion of life, and an end to the toxic wasteful exploitation and desertification of landscapes that had preceded it.
***Brad Field's eldest son, the current chief executive (caps) of the Australia Transformation Project, proudly stood up to give a tearful eulogy.
***"We celebrate the life of my father today, (period not a comma, caps on -W) we remember a man who was written off by the most important people of his time for the vision he carried in his heart. They told him that what he wished to do was too expensive, that it could not be done.
***"I will miss him, (period not a comma) I think we will all miss him", (comma inside the quote marks) he sobbed, unable to hold back his tears anymore.
***And the whole of Australia cracked and cried, in the same moment, so united were they in their grief for this great man, that had changed the world and made it forever green (period)

My review has been submitted for consideration in "Good Deeds Get CASH!" .