Or, air pollution - put scrubbers on smokestacks. The solution must come from a change in human behavior. These changes can be prompted from our various institutions such as religions, morals, governments, economics. As an example, how are we going to solve the arms race problem - change our attitudes. As another example, HIV is currently a problem with no satisfactory technical solution.
Many environmental problems fall into the class of problems with no technical solutions.
That is, there is either no quick fix to the problem from the lab, or the fix is so expensive or otherwise unattractive to make it non-existent. Thus, these problems will only be solved by human behavioral changes. Population growth is one such problem - there are ways to control human fecundity, but they rely on individual application. Destruction of a commons is inevitable - unless freedom is restricted . This is another lesson from Hardin's article.