As a new study has found that sea levels are rising more rapidly than the rest of the world has been aware of, it has highlighted the need to address the issue head-on.
The paper, published in the journal Nature Climate Change, shows that sea level rise is accelerating, with the world experiencing at least three times as much sea-level rise than the average for the past three decades.
“It is now clear that the sea level is rising faster than the IPCC’s projections,” said lead author Dr Tim Dickson, from the University of Southampton.
“Our findings show the urgency to take urgent action to reduce the rate of sea level change, and to act now before the problem worsens.”
The study used satellite data to show the sea-levels are rising faster and faster.
It found that the rate at which sea levels were rising is increasing in tandem with the global average, with sea levels rising by 2.3mm a year since 1992, while global average sea-surface temperatures have remained stable at 2.1mm a decade.
The increase in sea-rise was accompanied by an increase in the amount of time it took for the sea to rise, from just 1.6 years to 3.5 years.
“The IPCC’s models predicted that sea-sea-level warming would continue to accelerate over the coming century, with global sea-tide rise continuing to increase from the 1990s,” said Dickson.
“But in the last decade the IPCC has been under pressure from sceptics to abandon its sea-water projections, despite the overwhelming evidence that they are reasonable.”
He said the study showed that sea surface temperatures are a key factor in sea level trends, and it was the most important indicator of sea-floor stability.
“If sea-salt levels had risen as fast as they are, the world would have been able to cope with a much higher proportion of coastal flooding and storm surges by now,” he said.
“Now, by relying on the IPCC models, the IPCC is giving the impression that it’s OK to continue to sink into the sea.”
The researchers used satellite-based measurements of global sea level from 1996 to 2013 to calculate the rate and extent of sea change.
“Using a new method we have built into our model, we were able to estimate the rate by which the rate increases with the rate on the land,” said Dr David Anderson, lead author of the study.
“This is the most accurate measurement of the rate change that we have had.”
“In fact, it’s much better than anything the IPCC currently has available.”
Dickson and his co-author, Dr David Turner, from Durham University, found that when it came to the rate per year, the rate has been accelerating for the last 25 years, and that it has accelerated for the next two decades.
However, they found that as the world began to realise the seriousness of sea levels, the rates of sea rise started to slow down.
“What we’ve found is that it actually started to get worse and worse from the late 1990s to the late 2000s, and then began to pick up again,” said Anderson.
“We are now seeing a rapid decrease in the rate that is happening right now, which is probably due to a combination of global warming, increased coastal development, and a reduction in the number of coastal areas that are vulnerable to flooding.”
“We’re now seeing some very slow rate increases over the last few years, but they’re all still too high, which means that they’re very, very large.”
“The trend of global temperature rise is increasing very quickly, and we’re seeing the global sea levels rise faster than any other period in human history.”
“These results are very important to all of us, and will be of great interest to policymakers and the global community as they try to manage this rapidly accelerating change.”
The research is based on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, which can detect changes in Earth’s climate.