Sea level rise may be accelerating

Climate change predictions are not fixed, they keep needing to be adapted as more research results become known.

A new Australian study appears to explain a previous puzzle. Radio NZ reports in Sea level rise accelerating – study.

Satellite data dating back to 1993 appeared to show sea level rise accelerating in the 1990s and then slowing over the following decade.

But a new study claims that was incorrect due to early inaccuracies.

Sea level rise accelerated faster in the past two decades than it did for the majority of the 20th century according to a new study.

The report, published in the journal Nature Climate Change, corrected an anomaly that had puzzled the scientific community for years.

Satellite data dating back to 1993 appeared to show sea level rise accelerating in the 1990s and then slowing over the following decade.

Over the past five years, researchers from the University of Tasmania have been using tide gauges to check the satellite data.

Lead researcher Christopher Watson said they now thought they had the answer.

“Now, once we make a correction for how much land motion is at the tide gauge, or how much it’s moving up and down, we’re able to get a better picture of the really small inaccuracies within the altimeter record.”

He said the study suggested satellites marginally overestimated the rate of sea level rise in the first six years and that distorted the long-term picture.

Revised data suggested the rate of rise actually increased over the past 20 years.

“What we can see here is sea level clearly rising over the 20-year satellite altimeter record with acceleration in the record,” said Dr Watson.

If this is accepted then a few climate models may need to be adjusted.

Report co-author John Church, a fellow of Australia’s CSIRO science agency, said sea levels were predicted to rise by up to 98 centimetres in the next 85 years.

He said that would affect more than 150 million people living in low-lying coastal communities.

“If we have major mitigation, then we can limit that rise to be somewhere between 30 and 60 centimetres during the 21st century,” he said.

Two things are certain about climate change – the research will continue and the arguments will continue.

Nature Climate Change article: Unabated global mean sea-level rise over the satellite altimeter era

1 Comment

  1. Alan Wilkinson

     /  13th May 2015

    When the data doesn’t give the result you want, adjust it until it does. Funny how this sort of paper never makes the news headlines:

    Now from the Geological Society of America:
    http://geology.gsapubs.org/content/early/2015/04/27/G36555.1.abstract?papetoc

    Coral islands defy sea-level rise over the past century: Records from a central Pacific atoll

    P.S. Kench, D. Thompson,M.R. Ford,H. Ogawa andR.F. McLean

    Abstract

    The geological stability and existence of low-lying atoll nations is threatened by sea-level rise and climate change. Funafuti Atoll, in the tropical Pacific Ocean, has experienced some of the highest rates of sea-level rise (∼5.1 ± 0.7 mm/yr), totaling ∼0.30 ± 0.04 m over the past 60 yr. We analyzed six time slices of shoreline position over the past 118 yr at 29 islands of Funafuti Atoll to determine their physical response to recent sea-level rise. Despite the magnitude of this rise, no islands have been lost, the majority have enlarged, and there has been a 7.3% increase in net island area over the past century (A.D. 1897–2013). There is no evidence of heightened erosion over the past half-century as sea-level rise accelerated. Reef islands in Funafuti continually adjust their size, shape, and position in response to variations in boundary conditions, including storms, sediment supply, as well as sea level. Results suggest a more optimistic prognosis for the habitability of atoll nations and demonstrate the importance of resolving recent rates and styles of island change to inform adaptation strategies.