We have been hearing a lot recently about coral reefs dying because of global warming.  And that will cause many fish, crabs, and lobsters to die.  One thing I haven't heard mentioned in any of these stories is the possibility of mutations developing.  It's known that in areas where underwater volcanic vents keep the water unusually warm, fish, sponges and tube worms grow much larger than normal.  
    Will the warming of the ocean water cause mutations also?   Will the death of some species cause others to find new food sources?  Will eighty and ninety foot sharks start attacking fishing and pleasure boats?  Will mutant barracudas start swimming up rivers looking for food?  Will mutant dolphins or whales start coming on land again to hunt for food?  Will polar bears adapt to living in the water all the time?  Or maybe one of those lobstrosities from the Stephen King novels?  The largest lobster on record is 44 pounds and there is no reason to believe that there are not larger ones in the ocean that, with global warming could become 100 or 150 pound monsters that would come ashore at night to hunt.
    Most scientists will say none of this is going to happen because it takes millions of years for such changes to happen in a species.  While that is usually true, there is also some evidence that when changes occur on the planet, such as an ice age, some species manage to adapt and mutate rapidly to survive.  Plus there is increased solar radiation reaching Earth and radiation is also known to trigger mutations.  It's total speculation, of course, but something to think about.