Traditional owners are devastated by the lack of recovery at the site of Australia's worst recorded mangrove dieback and are calling for action to limit climate change threats.

Key points: Scientists have said the severity of the mangrove dieback is on a par with Great Barrier Reef bleaching

Scientists have said the severity of the mangrove dieback is on a par with Great Barrier Reef bleaching The Top End is experiencing sea level rise at two to three times global averages

The Top End is experiencing sea level rise at two to three times global averages The CSIRO is warning the world is not on track to halt sea level rise

Traditional owner Patsy Evans had hoped there would be signs of recovery at the site of the mangrove dieback, in the Gulf of Carpentaria.

But during a recent visit to the area for the first time since 2015, when she and her husband alerted the Northern Territory Government to the extent of the damage, she was devastated by the scene.

"This is bad, worse, it's unbelievable, I can't even believe what's happening here," Ms Evans said.

She said she wanted policy makers to see how climate change was affecting the land near her home on the Limmen River, 750 kilometres south of Darwin.

"Go out and see what's happening, be aware and look at it, and don't make decisions where you are," she said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 4 minutes 50 seconds 4 m 50 s The Top End is on the front line of Australia's most severe climate challenges

The mangroves were once nurseries for the mud crab, barramundi and prawn fisheries, but now consist mainly of dead trees and dusty earth.

The few live seedlings coming through are exposed, and vulnerable to damage from the fallen dead trees.

"Through the mangroves you get a lot of bush tucker, mud mussels and shells, and they're all just dead. It just makes me feel sad," Ms Evans said.

Scientists from Queensland and Northern Territory universities said one contributing factor was a temporary drop in sea levels, caused by a change in the trade winds, which left the forests unusually high and dry.

But they said another factor in the dieback along 1,000 kilometres of coastline was climate change and a sharp increase in the sea temperature.

Dead shellfish now line the coastline, where mangroves used to thrive. ( ABC News: Jane Bardon )

On par with Great Barrier Reef bleaching

"We can't see any other driver of the dieback other than the extreme climatic envelope has shifted," Charles Darwin University professor Lindsay Hutley said.

Dr Hutley said the extent and duration of the dieback was on a par with the severity of Great Barrier Reef bleaching.

"It's the canary on the coastline; it's quite significant, probably globally significant," he said.

Madeline Goddard and Lindsay Hutley are seeing mangroves move inland. ( ABC News: Jane Bardon )

Along with colleague Madeline Goddard, Dr Hutley has been researching other impacts of climate change on mangroves.

They've found mangroves have been adapting to climate change and sea level changes by moving inland.

"In parts of the Top End we are experiencing some of the highest sea level rises in the world," Ms Goddard said.

"If we give mangroves space, the whole forest can move landward, until they hit manmade barriers, and then they are at risk of drowning.

"That they are shifting, to this large degree, because of these climate change influences, is a warning to us."

Polar icecap melting underestimated

The CSIRO has mapped the average sea level rise of the Top End at between six and 13 millimetres a year — two to three times the rate off southern Australia and the global average.

Professor Stephen Garnett has said the Top End may have a sea level rise of a metre by the end of the century. ( ABC News: Jane Bardon )

"That is partly because north of here we've got the Arafura Sea, which lies on top of the Continental Shelf, and so it's very shallow and so it warms up very quickly," Stephen Garnett from the Charles Darwin University Research Institute for the Environment said.

"So, we're looking at a metre rise by the end of the century, and we've already had a fifth of that," Professor Garnett said.

CSIRO Sea Level and Coastal Extremes senior researcher Kathy McInnes said even if the Global Paris emissions reduction targets were met, that would not be enough to stop this rate of sea level rise.

Dr McInnes said the impacts of polar icecap melting on sea level rise had also been underestimated.

She warned that would leave the Top End vulnerable to more impacts like mangrove dieback.

"We can expect greater frequency at which extreme events can occur, and this can lead to cascading impacts on society and ecosystems like the massive dieback of mangroves," she said.

"The compounding effect of that can be felt years down the track because of the flow on effect into our fishing industry, when stocks of both prawns and fish species drop."