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Has the law caught up with science in North Carolina?

  • 25 Jun 2012, 17:00
  • Carbon Brief staff

A new bill that would prevent planning authorities from being guided by scientific predictions about sea level was passed in North Carolina last week. But now it appears the bill may have been defanged, just as new research is published that says the state and others on the East Coast are in a sea level rise 'hotspot'.

So what's going on? Here, we summarise the latest somewhat ridiculous tussle between US climate scientists and legislators over scientific research.

Outcry

There was outcry over the decision by state legislators to approve a bill which would 'all but outlaw' projections of sea level rise made by the state's scientific commission, in favour of a lower estimate put forward by a group representing local developers.

The bill has been seen as an attack on scientifically-informed policy making, and following some rather scathing coverage of the decision, last Thursday a North Carolina legislative committee met to reconsider, according to the Huffington Post.

There was a degree of rollback: Committee chair Pat McElfraft told HuffPo that amendments to the contentious bill will include requiring more sea level studies by the Coastal Resources Commission, which gives planning permission to new projects, over the next three to four years.

There will also be no law dictating that calculations may only be based on historical trends, as was suggested in the original bill - which would have put  sea level rise by 2100 at just 20 centimetres.


However, regulators will still not be able to use work by a group of scientists, the Science Panel on Coastal Hazards, which estimated future sea level rise to accelerate to around one metre by 2100, threatening more than 2,000 square miles of coastal land.

Representative Ruth Samuelson told the Huffington Post:

"Before we set coastal policy for 100 years we need to make sure we're looking at it carefully."

So although a historically-based projection - originally put forward by NC-20, a group representing coastal development companies and other businesses in response to the scientists' submission - won't be enshrined in law, North Carolina is still not acknowledging studies that project higher levels of sea level rise.

It puts the Coastal Resources Commission in a strange position - how is it going to assess planning applications over the next few years?

Ocean circulations

Meanwhile, new research has been published that supports the Science Panel's 2011 suggestion that sea level rise is accelerating.

The US Geological Survey released a study today concluding that the east coast of the US - from Massachusetts to North Carolina - is a sea level rise "hotspot". Sea levels are rising at a rate three to four times faster than the projected global average in this area, it says, in part due to circulation patterns in the ocean and atmosphere which distribute water unevenly.

The study supports data from climate models suggesting that not only is sea level rise likely to accelerate in the future, it is already doing so now.

North East Hotspot SLR
Difference in rate of sea level rise relative to global average. Source: Nature Climate Change

We asked Dr Abby Sallenger at the US Geological Survey at St Petersburg, Florida what this could mean for North Carolina. She said North Carolina is at the southern edge of the hotspot, adding that "the data at present show accelerations of sea level rise in the northern half of the state."

Sallenger told us, however, that other processes could alter the rate of sea level rise in the future. So we can't necessarily say that this acceleration will continue.

Sea level rise up to two degrees celsius

Meanwhile, another paper from the Potsdam Institute for Climate Impact Research says that even if humans manage to keep temperature rise to within less than 2 degrees celsius - the amount of warming suggested by the Intergovernmental Panel on Climate Change to be the upper limit for harmful climate change - global average sea level may still rise by between 75 and 80 centimetres by 2100.

The research looked at observed sea level rise over the past 1,000 years as well as scenarios for future greenhouse gas emissions, and added estimates of the effects of melting ice on sea level rise to existing IPCC projections.

According to Michiel Schaeffer, the lead author of the study, since oceans and ice masses respond to temperature increases much more slowly than the atmosphere does, "emissions today will determine sea level rise for centuries to come". The paper argues that halting sea level rise over the next few centuries won't be possible without extensive geoengineering efforts to remove carbon dioxide from the atmosphere.

Co-author Stefan Rahmstorf says the potential impacts of such rises could significantly increase the frequency of severe flooding in areas such as New York, and significantly affect low-lying countries such as Bangladesh and the small island states.

What does this mean for North Carolina?

These recent studies broadly agree with work done by another scientist, Ben Horton, whose studies of sediment cores in North Carolina show a " consistent link between sea surface temperatures and changes in sea level for the past millennia".

So assuming that the North Carolina government decides to take scientists' future sea level predictions into account, it will presumably be planning for at least a one metre rise in sea level by 2100.

However, with the legal status of the predictions in limbo for at least three years, it's likely that construction projects along the coast will be given the go-ahead before another scientific review happens. After a two-year legislative process, North Carolina has basically managed to ignore any sort of prediction of future sea level rise, scientific or not. Inertia can be hard work.

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