Impacts of climate change on world heritage coral reefs: a first global scientific assessment

Abstract

Since 1972, the UNESCO World Heritage Convention has
\nunited the world around a shared responsibility to protect
\nnatural and cultural places of Outstanding Universal Value
\n(OUV). The World Heritage List includes 29 natural, marine
\nproperties that contain coral reef systems. Stretching around
\nthe planet, these globally significant reefs include icons such
\nas the Phoenix Islands Protected Area (Kiribati), the Great
\nBarrier Reef (Australia), Papahānaumokuākea (USA), Belize
\nBarrier Reef Reserve System (Belize) and Tubbataha Reefs
\nNatural Park (Philippines). They are recognized for their unique
\nand global importance and for being part of the common
\nheritage of humanity.
\nCoral reefs are ecologically and economically important
\necosystems found across the world’s tropical and sub-tropical
\noceans. Despite covering less than 0.1% of the ocean floor,
\nreefs host more than one quarter of all marine fish species (in addition to many other marine animals). They are the most
\ninherently biodiverse ecosystems in the ocean – comparable
\nto rainforests on land. These ‘Rainforests of the Sea’ provide
\nsocial, economic and cultural services with an estimated value
\nof over USD $1 Trillion globally. For example, the complex
\nthree-dimensional structure of reefs not only provides habitat
\nbut also dissipates wave energy to protect coastlines from
\nerosion and damage. Coastal protection and human use
\n(including tourism, recreation and fishing) supply the greatest
\neconomic benefits from coral reefs to over half a billion people
\naround the world.
\nDespite their importance and value, most coral reefs are
\nunder enormous pressure from a range of different human
\nactivities globally including agricultural run-off, urban
\ndevelopment, and over-fishing. Superimposed on these local
\nthreats, increased ocean temperature has caused the death
\nof corals around the world in recent years. At this point, rising
\natmospheric carbon dioxide caused by human activity is the
\ngreatest threat to coral reefs globally, primarily due to ocean
\nwarming but also due to ocean acidification that ensues.