The era of nuclear weapons and of global climate change poses dangers to human existence which must be addressed in coming decades.
In the century from 1945 to 2045, the human community has been and is required to confront two existential problems.
The first is its capacity to damage and possibly even destroy itself through new weapons technologies. It survived the first dangerous phase of the nuclear era less by wise decisions than by good fortune, and it now has an opportunity to render nuclear weapons obsolete. The less widely acknowledged danger of new bio-weapons may actually be more problematic, but progress on both issues could be rapid if a new period of serious multilateral engagement can be fostered by 2009-10.
The second problem is the recently developed capacity to have an impact on the entire global environment.
Here, too, the message is mixed. Ozone depletion was in a sense the "marker" of humanity’s new capacity. It was specific and had a relatively straightforward solution but the rapidity of international action in the mid-1980s was still impressive. Climate change is a problem of far greater scope, and will be considerably more difficult to handle. At the same time, awareness of the issue is growing month by month.
In this respect, it is the period through to around 2015 that is the key. If genuinely major changes are made in that time – perhaps through a unique combination of citizen action and political acumen – then the prospects could be good. By 2045, the world may have learned both to control adverse technologies and safeguard the biosphere. In the context of the entire century, it may well be the seventh decade – 2005-15 – that proves pivotal. The world has entered interesting times, and they are about to get more so.