The effects of global warming are expected to cost California up to $15 billion annually by 2050. In a summary of cost analysis presented to Gov. Schwarzenegger's climate advisers, the impacts of sea level rise, wildfires and other events associated with global warming are expressed as a dollar amount. If losses are up to $15 billion annually, that would represent double or triple the budget of some large cities. Much of California's population lives in coastal and fire prone areas, meaning that even relatively small changes in sea level, precipitation or temperature can easily exacerbate an already threatening situation.
If nothing is done globally to reduce emissions, hotter temperatures will lead to rising sea levels that will flood property in the San Francisco Bay area, lead to lower crop yields and water shortages, produce more intense wildfires and cause more demand for electricity to cool homes.
The story of California is extreme, but not necessarily unique. Most of the world will be adversely impacted by global warming, and that is going to hit people in their pocketbooks. The Stern Review , a large study financed by the British government estimates that the impacts of inaction on global warming could cost the world 20% of global GDP every year! That same study said that the cost of prevention would not be cheap, but would only cost a small fraction of the cost of inaction.
I feel like there is an old adage that applies to situations like this, an ounce of prevention is worth a pound of the cure.