Global sea levels could go up by as much as 1.9 metres by 2100, which is almost three times the rise predicted by the Intergovernmental Panel on Climate Change (IPCC), said a new study by German and Finnish researchers.
The authors of the study, which appeared on Monday in the journal Proceedings of the National Academy of Sciences, used a climate model to look at how changes in glacier melt could affect rise in global sea levels over the next century.
The IPCC didn’t include all these changes in its 2007 predictions, arguing that the science didn’t yet exist to model them.
The PNAS study isn’t the only recent study to take issue with the IPCC’s conservative estimates. Last week, the Scientific Council for Antarctic Research suggested that global sea levels could rise by as much as 1.4 metres over the next century.
A study published on Sunday in Nature Geoscience suggested that long-term factors such as changes in forest cover and land ice could accelerate the effects of climate change in the next century, leading to stronger climate change effects than predicted by the IPCC.
“We know that many long term processes have not been included in the climate change projections [previously] used by IPCC,” said Kevin Trenberth, one of the lead authors of the 2007 report.
World leaders have only recently managed to build a political consensus to cap future temperature rise to 2 degrees Celsius above 1990 levels, the target identified in the IPCC’s 2007 report.
Even to match the two-degree target, the world will have to limit total carbon dioxide emissions to 1000 billion tonnes between 2000 and 2050. Between 2000 and 2006, the total emissions were a third of that.