Sea Levels Rising Faster than Previously Expected

According to new research, sea-levels are rising 60 perfect faster than central projections made by the Intergovernmental Panel on Climate Change (IPCC).

Although current rising temperatures seem to be consistent with the IPCC’s projections in the fourth assessment report, satellite measurements are showing that sea-levels are rising at a rate of 3.2mm a year, which is quite a bit higher than the estimated 2mm a year in IPCC’s projections.

Since IPCC projections are being used more often in decision making, the researchers believe that these findings are important for tracking how previous projections match the accumulating observational data. The study, which has been published in IOP Publishing's journal Environmental Research Letters, involves an analysis of global temperatures and sea-level data over the past twenty years. The analysis is then compared to projections made in the IPCC’s third and fourth assessment reports.

Results were obtained by taking averages from the five available global land and ocean temperature series. After removing the three known factors that create short-term variability in global temperatures (solar variations, volcanic aerosols, and El Nino/Southern Oscillation), the researchers found that the current warming trend is 0.16°C per decade, which is very close to IPCC’s projections.

For sea-level rise, satellite measurements showed that the current increase rates are 60 percent faster than IPCC projections. The study also shows that it is very unlikely that the increased rate is down to internal variability in our climate system and also shows that non-climatic components of sea-level rise, such as water storage in reservoirs and groundwater extraction, do not have an effect on the comparisons made.

Lead author of the study, Stefan Rahmstorf, said: "This study shows once again that the IPCC is far from alarmist, but in fact has under-estimated the problem of climate change. That applies not just for sea-level rise, but also to extreme events and the Arctic sea-ice loss."