“If the bee disappeared off the surface of the globe then man would only have four years of life left. No more bees, no more pollination, no more plants, no more animals, no more man.” ~ Albert EinsteinColony Collapse Disorder is the clinical name for the mysterious abandonment of bee hives. The bees aren't obviously dying, they are most certainly dying but there is no pile of dead bees either inside or outside the hive. The just seem to be disappearing in large numbers both in North America and Europe. Nobody knows the cause but there are several suspected culprits.
Replacing flowers with ringtones
One theory is that cell phones are disrupting the navigation of bees so they can't find their way back to the hive. A German study found that bees will not return to their hive if a cell phone is nearby. This has received a lot of press such as here and here, but the absence of the problem so far in Asia causes questions.
Killing them with confusion
The modern human habit of deliberately poisoning his environment with pesticides and weed killers has endangered bees in the past. A new nicotine-based poison called Imidacloprid, it goes by dozens of trade names, is effective against termites by confusing them so they cannot find their nests. It is widely used as a systemic poison on fruits and vegetables crops. This theory holds that the poison is having the same effect on bees.
Crops with pesticides genetically modified into their cells are known to be able to pass on that trait to weeds flowering nearby, killing bees by proxy. As much as I hate GM foods, this theory is a bit weak. European bees are suffering too and Europe does not have anywhere near the level of genetically modified crops as the United States.
Some people are blaming Sunspots. This is a theory I can't approach understanding. This is the favorite theory of rightwingers who can't stand the notion that humans might be harming the Earth.
Whatever the cause, if we can't reverse the trend soon beehives will disappear from much of the planet. With them will disappear citrus, nuts, many vegetables, and many many flowers. Much of agriculture depends on the pollination of bees. Almost all of the beauty of God's creation depends upon bees as well. Einstein may be right, humans will not survive on this Earth for long without the honeybee.