Two weeks ago officials reported that around half of the northern part of the barrier reef have been bleached. If the bleaching trend continues, most of the coral could die. Reasons why this is happening include rising temperatures and a strong El Niño. If temperatures remain high, this world heritage site may become endangered.
Read more at: http://www.theguardian.com/environment/2016/apr/11/mass-coral-bleaching-now-affecting-half-of-australias-great-barrier-reef