Climate experts gathering this week to prepare data for the UN climate conference in December are warning that sea levels could rise by a metre this century

More than 2,000 scientists gathered in Copenhagen on Tuesday for the start of a three-day climate congress aimed at bridging the gap in climate change data that has emerged since the publication of the last UN Intergovernmental Panel on Climate Change (IPCC) report in 2007. The length of time needed to reach a consensus on that report meant that much of the scientific data contained in it stems from 2005.

The IPCC report received some criticism for not taking into account the melting ice sheets of Greenland and the Antarctic when estimating future rising sea levels, and new knowledge obtained since then and presented at this week’s congress suggests that sea levels could rise by more than a metre by 2100 – far more than the IPCC estimate of between 18 and 59cm.

Approximately 10 percent of the world’s population, or 600 million people, live in flood-danger areas and scientists warned the impact of sea level rise on them will be ‘severe’.

Dr John Church of the Centre for Australian Weather and Climate Research said recent satellite data and ground observations show sea levels rising at least 3mm per year – a rate well above the 20th century average.

‘Sea levels are currently rising at a rate that is above any of the model projections of 18 to 59cm.’

Professor Stefan Rahmstorf, a leading expert in oceanography and paeloclimate, has spent years studying the climate conditions of the past and sees a direct link between rising temperatures and increased sea levels.

‘During the Eocene period about 40 million years ago the planet was virtually free of ice, temperatures were about 4 to 5 degrees higher than today and sea level was about 70 metres higher than now,’ said Rahmstorf.

Rahmstorf also highlighted the difficulties with the current ice prediction models, which calculate the ice melting from the top of the ice sheets. However, the models have difficulty measuring the ice which is melting directly into the sea.

He continued to highlight that the models used for the IPCC report showed a sea level increase of 1.2mm per year between 1961 and 2003, while the data showed it to be 50 percent higher at 1.8mm per year.

‘So it appears that it is actually increasing more than we can predict and we have to conclude that the physics-based models are not up to the task of predicting sea level rises very well.’

Rahmstorf said that the sea level rise will likely accelerate as the planet heats up, unlike the steady rise predict by the IPCC.

The conclusions of the conference will be published in June and presented to politicians negotiating a follow up to the Kyoto Protocol in Copenhagen in December.

The chairman of the IPCC, Dr Rajendra K Pachauri, also addressed the delegates on Tuesday, warning that even if greenhouse gas emissions did not increase above current levels, then global warming would still continue to increase for the next two decades.

‘If we want to stabilise temperature increase to between 2 and 2.4 degrees, meaning we stabilise emission concentration to similar levels of today, then it requires that CO2 levels peak no later than 2015. That’s just six years and highlights the urgency of taking action now.’