What is a responsible lifestyle for planet earth ?

Big subject - I am only going to tackle 1 question here,  and only in relation to Food .Someone else can tackle some others
Can the earth sustain the numbers of people on it at present ?-That is,  if all the people who are currently using land unsustainably stopped doing it over the next 100 years? Ans  Yes   Is such an idea impossible ?    Ans No

Some would say we can't ( no to the first question ) because they believe few human land uses are " sustainable ". That's their view but I don't know anybody who says that who is really building from the sites up( only way to prove the case) . Sure, the way we cage some animals is of  great concern to many of us  ; Squeezing the last drop out of the system has been an unsound  preoccupation of my colleagues in agriculture  for decades, and it clearly goes against the summary traditions of those who walked the path of faith before us -
HOW questions Because the volume of food is not a problem for the earth, the issue of  just how or where its grown , is the issue. Just like chooks can produce eggs on free range if we are not pushy , grazing animals can live full lives if we want to be patient for their meat. . Doing things a lot better is possible and it can be just as productive if we do it together.

We need to change how and where we grow  food in certain places , as a very  top priority.
WHERE questions   The most amzing thing is that we can grow all the food we need sustainably if we just grow it in the sustainable places available ( a greenhouse is a sustainable place, but its not cost effective for all ) The hardest thing for those of us who have studied and advised farmers for eons is that there is always a small percentage who are trying to grow something where they shouldn't, and they mostly, can't see its unsustainable.They waste resources and they hardly make a living but they often can't get out of the trap without help.
If we dealt with this issue we would not only produce just as much,  if not more food , we would reduce the pressure on the earth greatly and the pressure on the poor enormously . Another  good thing is that , with help ( farmers like the sort of help that means they get more back they did last time-) farmers can choose to invest in one area of land and not another- one land use and not another.  Governments need to encourage this too. Its not impossible because the cost to ANY government is not high --to give rural producers a more sustainable path to payments .  They don't do it enough ,so please encourage them to do this in your area.

Note: I am just talking here of current agricultural production land uses that we know can be carried out for thousands of years without loss or degradation of the natural resources involved.

As a production ecologist , I would suggest that about 30% of the people on the earth are currently not using the land in a way which can be sustained for the next 1000 years. These areas are  mainly in rural areas in hill country. The people involved are largely the poorest people we know know of .
In the last 100 yrs in the West , most of  what we used to call 'marginal lands' have been moving to sustainable uses . This improvement has involved a large but effective displacement of people  and there is little reason why the same can't happen in all continents and climate zones to bring the small percentage of marginal land uses into line with long term productive ones .
There is therfore  hope that it the next 100 years the poorest of the poor could follow a move away from unsustainable land uses . Hope,  if we focus on the target .......and don't offer tokens and gifts.
A suggested sustainable target
A  support mechanism to help people move away from using marginal lands, in the way they do it,  is a critical area for you to support if you want everyone to share in a sustainable lifestyle . How about YOU add something below ?