There are no limits to growth: CSIRO says so

Given these kinds of multiples, a 35% reduction in materials demand (i.e., only 25% per capita given that the analysis envisages a 37 million population in 2050) would not get us far towards a global consumption rate that is sustainable and possible for all.

Finally the paper actually states that their most optimistic scenario would

result in a vast increase in materials use, i.e., multiplying by more than 2.3 times. Given the assumed GDP growth multiple of 2.7 this would be a small relative decoupling but what we urgently need is a dramatic absolute decoupling. The WWF Footprint measure indicates that world resource use must be reduced by at least one-third to be sustainable, and for materials this suggests that a sustainable rate might be around 48 billion tonnes p.a. How plausible is it then that it could rise to 183 billion tonnes p.a. while the associated scarcities and ecological impacts can be handled, and without questioning growth and affluence?

Thus it would seem that a) it is highly implausible that anything like the expected/assumed decoupling could be achieved, b) no reason is given to expect that it could, c) in fact even when Schandl et al. make very implausible assumptions they admit decoupling does not result, and d) even if the most optimistic CSIRO rate was achieved was it would leave Australian levels of resource and ecological impact far higher than those enabling a sustainable world (explained further below.)

Bio-sequestration.

The second of the two big assumptions the paper's optimism depends on is to do with the potential for bio-sequestration of carbon. It says that in 2050 large quantities of carbon based energy would still be being used and up to 59 million ha would be planted to take carbon from the atmosphere. (All our cropland is only c. 24 million ha and all our agricultural land is about 85 million ha.) The yield assumption does not seem to be stated; is it 15 t/ha, or the more like 5 t/ha likely from a very large area of more or less average land?

The main problem with the use of land to soak up carbon via plant growth is that after about 60 years the trees are more or less fully grown and will not take up any more carbon; what then?

The implications of this do not seem to have bren considered. It means that in the second half of the century an amount of new planting would be needed each year that was big enough to take out the amount of carbon emitted that year. Given that the economy in 2050 is expected to be 2.7 times bigger than it is now, and still growing at a normal rate, the area to be planted each year would be substantial, and increasing.

Fig. 2 shows that by 2050 a net 200 million tonnes of CO2 is supposed to be would be taken out of the atmosphere each year. That is, in addition to taking out the emissions generated by the large amount of fossil fuels still being used in 2050 (which seems to be around 1.825 EJ), another 220 million tonnes would be taken out (the amount from power plus transport), making a total in the region of 450 million tonnes/y. Assuming 10 tonnes/ha/y forest growth (it would be more like 5 t/y for a large area), taking out approximately 36 tonnes of CO2/ha/y, the additional area to be planted each year would be 12.5 million ha, and more when it is to cope with an economy that is growing.

When I put to the authors this point about the forests ceasing to take up carbon, the reply was"… the carbon sequestered by plantings on currently cleared satiates after a period and does not provide a permanent flow." This is difficult to understand because it flatly contradicts their entire case. Their defence of the possibility of growth and affluence depends heavily on the capacity of bio-sequestration to take out as much CO2 each year as we are putting in but this reply admits that their strategy could only do that until the trees are fully grown.

Randers, one of the original Limits to Growth authors, doesn't think we will run into limits problems by 2050, but he thinks by about 2070 they will be catastrophic. The time line isn't crucial; the original book wasn't concerned with when we will hit the wall; it was concerned that we are going to hit it. At the best the CSIRO paper might be taken to provide some reason to think it will be later rather than sooner, but it doesn't give us any good reason to think we won't hit it. Yet the paper is being taken to mean there are no limits to growth to worry about.

Has the carbon embodied in the production and transport of imports been accounted? It would seem that the 2050 economy would have to be even more dependent on services than the present economy, meaning there would be heavy importation of goods no longer produced in Australia. The energy, carbon, resource and Third World justice effects of imports is only beginning to be attended to, and the picture is disturbing. For instance for a rich country the amount of carbon emissions due to imported goods is typically as great as or much greater than the amount released from energy production, which is all we talk about. (And it shows up on the books of the exporting country, not the rich country consuming the goods.) Has the amount of bio-sequestration needed to deal with this been included?