Can the earth support 9 billion wealthy people?

As China and India continue to grow, we must ask whether the earth could support several billion more people at European levels of wealth. Michael Lind says yes:

...there seems to be no insuperable physical or ecological reason why 9bn people should not achieve something like the lifestyle of today's rich, with technology only slightly more advanced than that which we now possess.

Here is part of the argument:

As machines get ever cheaper, more people will be able to afford more of them. Today the combined mass of all machines, at more than a gigaton (Gt), exceeds the combined mass of human beings, about 1 megaton. The total amount of carbon, 5Gt, required to power and construct machines and electric utilities greatly exceeds the 1.3Gt global consumption of carbon by human beings, mostly in the form of food. As affluence grows, the amount of energy and raw materials "consumed" by machinery will escalate even more rapidly than human consumption. But this need not mean an end to the machine age. If manufacturing processes were to imitate the recycling that takes place in the biosphere, then most machine materials might be recycled to make new machines, rather than thrown away. And long before all fossil fuels were exhausted, their rising prices would compel industrial society not only to become more energy efficient but also to find alternative energy sources sufficient for the demands of an advanced technological civilisation - nuclear fission, nuclear fusion, solar energy, chemical photosynthesis, geothermal, biomass or some yet unknown source of energy.

Here is more:

...agriculture, including logging, accounts for about 21m square miles, or ten times as much land as that occupied by urban areas and reservoirs.

Cutting urban land use by half would free only 1m square miles or 2 per cent of the ice-free land surface, while cutting agricultural land use by half would free ten times as much land - 10.6m square miles, or 21 per cent of the earth's non-glaciated surface.

In Lind's view, producing enough meat for nine billion wealthy people is likely to be the biggest problem. In my view, the biggest problems are ones of transition, rather than the end-state. China could get much richer before it moves close to environmental "best practices"; right now per capita income is just approaching that of Guatemala.

A fun tidbit:

Lind quotes Paul Romer: "[if America continues growing] in 50 years we can get extra income per person equal to what in 1984 it had taken us all of human history to achieve."

Addendum: Here is the working link.