Climate change is the most serious threat to the Great Barrier Reef, according to a major new report.

Warmer ocean currents are also likely to remain a threat to the Queensland coral ecosystem for many years, the Great Barrier Reef Outlook Report 2014 said.

“It is already affecting the reef and is likely to have far-reaching consequences in the decades to come,” the 300-page report said.

Climate change remains the reef’s biggest threat, despite improvements since the last report five years ago.

While the northern third of the reef enjoys good water quality, other areas are in jeopardy.

“Key habitats, species and ecosystems in the central and southern inshore areas continued to deteriorate,” the report said.

Poor water quality from land-based run-off, coastal development and fishing remain concerns.

But the report noted progress in the rising numbers of humpback whales, estuarine crocodiles and loggerhead turtles.

The Great Barrier Reef Marine Park Authority has prepared the report with contributions from Australian and Queensland government agencies and scientists.

“More needs to be done at reef-wide, regional and local scales,” it said.

The report came ahead of the United Nations’ world heritage committee decision, due in 2015, on whether to give the reef “in danger” status.

At its annual meeting in June, Unesco decided it would give Australia until 1 Feburary next year to prove it was looking after the reef.