"[A]n international group of leading technological thinkers were asked to identify the Grand Challenges for Engineering in the 21st Century."
The Engineering Challenges site is running a poll to get some insight into what the top engineering challenges are for 21st century. Right now the top two have to do with energy (solar and fusion) which is no surprise give the recent rapid rises in energy costs. Stop by and take a look and vote if you feel strongly about one challenge over another.
What strikes me about this list is that to find solutions to almost any of them a multidisciplinary approach will be an absolute must. It seem to point to the fact that the age of lone inventor solving great challenges is over (and may have been over for a while) and that teams will have to tackle the next set of great challenge. Teams that understand sociology, engineering, physics and environmental science. Teams that can build complex math models that actually replicate and predict what happens in the real world. And teams that can work together like they were all sitting in the same room even though they may never have met face to face. May the best team win.