The nature and scale of changes described in Part 1 indicate that,
without additional policies, the global environment will degrade
further – from a situation that already raises considerable
concern. A crucial question, therefore, is how to halt and reverse
such trends.
While previous Global Environment Outlook (GEO) reports have
explored several scenarios looking at very different futures
(UNEP 2002, 2007), the emphasis of GEO-5 is on the choices and
strategies that could, from 2012, lead to a sustainable future.
This is advanced by looking at two very different storylines based
on a review of existing scenario studies:
• a view of the world in 2050 assuming business-as-usual
paths and behaviours – “conventional world” scenarios; and
• an alternative that leads to results consistent with our current
understanding of sustainability and agreed-upon goals and
targets on the road to 2050 – “sustainable world” scenarios