Resource Limitations of the 21st Century

Is overpopulation as bad as it sounds?

Ten years ago, if you had asked me what the most important problem to solve was, I would have told you immediately and without hesitation overpopulation. I have given it a great deal of thought since then and no longer have a way of knowing for sure.

We are nature. Everything we do, no matter what we do, is what "nature intended". On the other hand, we have the ability to choose our future. Or at least the illusion to do so. It is important to fight for whatever it is that you believe in. In general, events tend to culminate in some sort of balance. I'm a lot less worried.

A good method of measuring overpopulation is to find the ratio of available resources (ordered by priority) to the number of people who need them. One thing is often overlooked, however. The greatest resource of all is people. The more people we have, the more people there are to solve problems. We are dramatically under-utilizing the average person as a resource. Most people have no solid concept of what major problems there are that need to be solved. By connecting important problems to solve with the average person who would ordinarily have no knowledge of it, the likelihood of solutions being created would rise drastically. People wouldn't be able to stop themselves. Solving problems is much, much more stimulating and rewarding than, say, watching movies. Now the tough part is inventing an objective technique for identifying top priority problems to solve, and putting them in the hands of as many people as possible.

What are the most pressing resource limitations in order (2015)? In the US? In California? In Santa Cruz? Where are these answers?