Ramina raises a important point: how reliable are these data? We will be discussing the theory behind these estimates in a future class, but it might be worth a word or two now:
The footprint makes an estimate of the amount of land needed to sustain human food production, the physical land needed to produce our energy resources, the amount of land needed to produce our timber resources, the amount of land needed to sequester carbon produced from burning of fossil fuels etc. The tally starts to mount rapidly when we fly or drive a lot (lots of land needed to both produce our energy as as a sink for our wastes), when we eat a lot of meat (meat requires a lot more land to produce than vegetables (since the animals eat plants and do so inefficiently)), when we live in a large home that is not energy efficient.
Although, it is tempting to disregard this test as a tedious piece of enviro-promotion, my reading of this over the years is that the footprint in a fairly rigorously developed bit of modeling, and cannot be easily disregarded. It was developed by respectable academic scientists.
We will discuss this later but for now play around with this.
My footprint is 14 acres, we would need 3.2 planets to support >6 billion Liams. If I made our house more energy efficient (we usually keep our house colder that most people would like), bought more of our food locally (reduced transportation costs), and if I did not fly, I could get this down to 1.6 planets. We are planning to get solar panels for our house, and we are optimisitic that we can but more of our food from the farmer's market. I fly to several meeting for my job each year - at the moment it may be difficult to minimize this.
Thought I'd share
Liam