Big problems such as health care, feeding the world and addressing climate change don't necessarily require big solutions. In the 19th century, Ignaz Semmelweis helped save the lives of hundreds of thousands of women by getting doctors to wash their hands prior to assisting in the delivery of a new-born child. (Unfortunately, however, it still required the medical community nearly two decades to unlearn their stubborn and unhealthy habits.) 
Alas, in the 21st century, the number of infections in hospitals remains unacceptably high. Why? Many healthcare professionals still aren't employing good hygiene. If they were better at the simple act of washing their hands, the results would be impressive -- on the order of saving thousands of lives annually and preventing billions of dollars in unnecessary costs.
In the field of agriculture, it was the addition of ammonium nitrate -- a cheap but effective crop fertilizer -- which allowed the world's farmers to feed billions more people with the same land.
Continued advances in the field of genomics may also continue to increase the yield of corn, wheat and rice by making these crops more efficient in terms of how they utilize water and fertilizer. The result: More people can be fed using the same amount of land but with less impact on the environment.
In the automotive industry, it was the installation of the seat belt that saved the lives of thousands of motorists -- even though the device was at first ridiculed as "inconvenient, costly, and just a bunch of damn nonsense" by auto executives. The next life-saving advance could be the introduction of super-strong, super-light nanomaterials.
As strange as it may sound, the problem of hurricanes may also just need a simple fix. As Steven Levitt and Stephen Dubner outline in their delightful new book, Super Freakonomics, in may be possible to prevent costly hurricanes (which, since 2005, have inflicted an estimated $153 billion in damage to the United States alone) by deploying a few thousand "hydraulic heads" in those areas where hurricanes start. The devices work by bringing cooler water from the bottom of the ocean to the top thus cooling the surface temperature of the ocean water and preventing hurricanes from forming in the first place. The estimated cost: $1 billion.
On the bigger problem of climate change, Levitt and Dubner also outline the logic behind "Budyko's Blanket" -- a super high hose which would spew sulfur dioxide into the atmosphere -- which could theoretically cool the planet for a mere $250 million.
Now, to be fair, both the "hydraulic heads" and "Budyko Blanket" may not work and serious questions remain on both ideas. But the broader point is that when faced with big problems there is absolutely no reason why we must first look to "big answers" as the solution. Often, big problems can be solved with small solutions. After all, as a child, how many of your cuts and bruises were solved with a tender kiss from your mother?
