PBrosnanMansionMalibu1211_04_X17inset.jpgmansion disaster real estate malibu beach house

Pierce Brosnan recently sold his gorgeous Mediterranean estate on Broad Beach Road in Malibu for $2.79 million ... in order to move into this enormous, beachside Bali-style mansion also on Broad Beach Road that's been under construction for eight years. Back then, the 007 actor shelled out close to $45 million for the property.

Problem is ... the sand in front of this property has been eroded so much over the years that Brosnan and his wealthy neighbors are concerned that their oceanfront properties will soon be sitting up right against the water. As the sand gets washed away, so does the value of these pricey properties!

Residents living on the posh Malibu street have brought in massive boulders to protect their oceanside homes from the rising tides.

One of Brosnan's neighbors (two doors down!) is director Steven Speilberg ... who recently rented out his sprawling beach house to the Beckhams.

See more of Brosnan's diminishing property in our gallery below.