This is my attempt at predicting Environmental Sustainability [2007] - I'm sure everybody can come up with a different version. The graph is meant to illustrate possible trends only, and assumes that the currently observed enhanced global warming (additional to natural climatic changes) is precipitated by human activity.

[Note May 2016: we don't seem to be doing very well regarding behavioural changes. Buying cheap goods from distant places which often get discarded quickly, and probably not made responsibly regarding energy efficiency and pollution. Building new roads, faster cars, disregarding green belts ... I may need to steepen the curve downwards!]

1. You can make up your own vertical scale - could be in terms of sea level, number of species remaining, human mortality rate etc. I believe human mortality related to global warming is currently around 300,000 per year, but wars instigated by resource shortages and land degradation can have a big effect on this number.

2. If there are no significant behavioural or technological changes (black line), and the enhanced global warming trend continues, the future is unpredictable because the earth's behaviour cannot be modelled in this region.

3. If there are technology developments which could help sustain the environment, but they are not widely taken up, they will have little effect - hence the plummeting blue line.

4. My favourite line is the red one - preferably voluntary (worldwide) behavioural changes with technology advances. I've been optimistic and shown an improving situation in time but we can't recreate non-renewable resources and extinct species, and re-freezing ice caps or removing excessive greenhouse gases from the atmosphere could be tricky ....