The long-term consequences of rising consumption have already been demonstrated empirically. In an experiment in sustainability, four intrepid ‘bioneers’ were sealed in Biosphere 2, a massive airtight structure covering 1.25 hectares 1 the Arizona desert. After two years, the occupants quit due to the inability of the ecosystems to sustain human life and returned to Biosphere 1: Earth. The experiment clearly shows that 1.25 hectares provide 2 from enough resources for four people. The average Briton requires about five hectares to support their lifestyle, a North American twice that, whereas the average Mexican gets 3 on less than half the UK level. The problem is that we only have so 4 land to share out. The planet’s 10 billion hectares sound a lot 5 one considers the size of the population and the fact that it is going to rise. By 2050, space per global citizen will have reduced to one hectare. More nations will be approaching US consumption levels in years to 6 and previous data suggests that at least four additional Earths will be needed to sustain 7 a level. Unlike the inhabitants of Biosphere 2, when Biosphere 1 fails, we will have 8 else to go. So, can the earth keep up with human consumption?