Dorset sea levels are likely to rise by a metre – even if climate change limits agreed at the Paris international climate conference are implemented.

A sea level expert told a Dorset Coast Forum annual meeting that the changes were already underway and the 1m rise was almost inevitable even if global warming was kept down.

Dr Ivan Haigh, from the National Oceanography Centre at Southampton, said his research shows that sea level rises are not only increasing on the Dorset coast – but accelerating.

He told the conference, at Poole’s Lighthouse on Thursday, that current figures for the local coastline are showing a 3.3mm a year rise in average levels with storm averages much greater. At the same time the coast was subsiding at between 0.5mm and 1mm a year, according to most experts.

Dr Haigh said he worried that changes to sea levels, accompanied by sea temperature increases, might mean than by 2050 the world’s coral reefs would all be dead. The audience heard that locally the changes had already resulted in the breaking up of one third of the ‘ammonite pavement’ in Lyme Bay.

He said that of thousands of glaciers in the world, only three had shown any sign of growth in the last 150 years and there was plenty of evidence across the world of increased storms and higher rainfall as well as wildfires and drought.

He said that from 1880 to the present day, nine of the hottest average years had been in the last decade and 2019 might yet be the hottest of all.

Dr Haigh added that data showed in the 20th century there had been a 1.7mm sea level increase each year, but from 1993 to today that had reached 3.3mm a year for the UK, although some places in the southern hemisphere had seen rises of 10mm.

Other speakers at the Dorset Coast Forum meeting warned of the danger that pesticides and fertilisers posed to the earth’s natural balance, calling for a ‘nature first’ policy for the future, including returning some areas to their natural state and abandoning the idea that mankind would find solutions: “It’s all about culture change, not hoping that technology will save us,” said Chris Skelly from the Healthy Urban Microbiome Initiative.

Sam Scrivens, from the Jurassic Coast Trust, said that climate change and the resulting erosion and sea level rises were seen as the biggest issue for people the group had consulted during the year.

“Sea level rises may threaten our coastal communities and we have to look at how they adapt to and address that threat,” he said.

Other issues included how to find a balance between the number of visitors to the Jurassic Coast while at the same time protecting it.