A new study has warned that the Sundarbans' famed 'Royal Bengal Tigers', the world's largest abode of the big majestic cat, could be gone within 50 years, especially from the Bangladeshi part, because of constant rise in sea levels and climate change.

The study titled 'Combined effects of climate change and sea-level rise project dramatic habitat loss of the globally endangered Bengal tiger in the Bangladesh Sundarbans', carried out by a team of Bangladeshi and Australian scientists, revealed that constant rise in sea levels and climate change could bring a catastrophic situation to the mangroves of Sundarbans-the iconic Bengal tiger's last coastal stronghold and the world's biggest mangrove forest. It has been published in the journal Science of The Total Environment.

"Fewer than 4,000 Bengal tigers are alive today," said James Cook University's Professor Bill Laurance, a co-author of the study. "That's a really low number for the world's biggest cat, which used to be far more abundant but today is mainly confined to small areas of India and Bangladesh," he said.

"Spanning more than 10,000 square kilometres, the Sundarbans region of Bangladesh and India is the biggest mangrove forest on Earth, and also the most critical area for Bengal tiger survival," said lead-author Dr Sharif Mukul, an assistant professor at Independent University Bangladesh.

"What is most terrifying is that our analyses suggest tiger habitats in the Sundarbans will vanish entirely by 2070," said Dr Mukul.

The researchers used computer simulations to assess the future suitability of the low-lying Sundarban region for tigers and their prey species, using mainstream estimates of climatic trends from the Intergovernmental Panel on Climate Change. Their analyses included factors such as extreme weather events and sea-level rise.

"Beyond climate change, the Sundarbans are under growing pressure from industrial developments, new roads, and greater poaching," said Professor Laurance. "So, tigers are getting a double whammy--greater human encroachment on the one hand and a worsening climate and associated sea-level rises on the other," he said.

But the researchers emphasise there is still hope. "The more of the Sundarbans that can be conserved--via new protected areas and reducing illegal poaching--the more resilient it will be to future climatic extremes and rising sea levels," said Professor Laurance.

"Our analyses are a preliminary picture of what could happen if we don't start to look after Bengal tigers and their critical habitats," said Dr Mukul.

"There is no other place like the Sundarbans left on Earth," said Professor Laurance. "We have to look after this iconic ecosystem if we want amazing animals like the Bengal tiger to have a chance of survival," he added.

However, experts and Forest Department officials expect an increase in the number of tigers in the world's largest mangrove forest with the decrease in the activities of forest robbers and poachers in the Sundarbans.

They think the tigers of the Sundarbans are now well-protected and their movement is safe as the activities of forest robbers and poachers have decreased to a large extent following smart patrolling in the forest.

Forest Department data shows at least 49 tigers were killed in the last 14 years (2001-2014) since the illegal poaching of wildlife and tiger-human conflict is on the rise in the Sundarbans, the country's only natural tiger habitat with a range of 6,017 square kilometers. Besides, about 232 people were killed in tiger-human conflict during the period, according to a census conducted by the Forest Department in collaboration with WildTeam, an NGO working for tiger conservation in the country, under the Bengal Tiger Conservation Activity project funded by the USAID.

As the Sundarbans tigers survive combating various natural disasters, there is no chance of their disappearance from the mangrove forest even if all the tigers get extinct from the rest of the world, said wildlife expert Prof Md Anwarul Islam, WildTeam chief executive and a teacher of Zoology department at Dhaka University.

He said if all the tigers are lost from the rest of the world, there is lesser chance that they will become extinct from the Sundarbans. "The Sundarbans won't survive if the tigers don't survive," he said.

According to sources, the number of tigers in the world's forests has dwindled to only 4,000 from 1 lakh over the last 100 years. Three sub-species of tiger out of total eight have already become extinct from the world due to due to unchecked poaching and destruction of natural forests.

According to the Tiger Census 2015, tiger population declined to only 106 tigers in the Bangladesh part of the Sundarbans in 2015 while it was 440 in 2004.

Striped big cats used to be found in 13 countries even one year ago but the number of the countries has now stood at 12 with the majestic cat going out of existence.