- Reality: Local sea level is rising, and the rate of rise has been increasing. (Note, by the way, that this isn't true of all areas. Global mean sea level is rising and accelerating, but some local areas are seeing a local sea level fall -- the land is rising faster than the water due to solid earth activity. But the examples below come from areas where it is true.)
- Reality: This increases the area that can be affected by storm surge if nothing changes.
- Reality: It means some areas currently occupied will go below sea level if nothing changes.
- Reality: Those previous 3 mean that if nothing changes, more people will be affected, possibly killed, than already are, each year or decade.
Given those realities, it would be reality based decision making to respond:
- I don't care, let the low-lying areas drown.
- Let the buyer beware.
- We should rezone to have less property in the way of the storm surge.
- No new building in the areas that already flood more than once a decade.
- If anything bad happens, we'll declare a state of emergency and let taxpayers from the rest of the country bail us out. Too bad, though, for the people who are killed.
- We'll build a dike to keep the water out. After all, that's what the Dutch have done.
- The cost of response is greater than the value of the lives and property that would be destroyed, so don't respond.
- The cost of rebuilding after this predictable event destroys the area is good for the economy.
- ....
- You can't make any decision about sea level response for at least 4 more years (passed both houses in NC, might be vetoed by the governor)
- You cannot use your scientific understanding of the issue to make your projections for the future (only past trends were allowed by this bill) (this passed the NC senate, but did not pass both houses)
- Sea level rise is a UN Agenda 21 conspiracy
- Ice melt can't change sea level
- God won't let climate change hurt us*
- Delete reference to climate change from scientific reports. "We stayed away from human-induced climate change, but we felt like we had to talk about sea-level rise," he said. "After all, it's been happening for 12,000 years. We were surprised the data on sea-level rise became a contentious issue."
- ... your contributions here ...
The reality-based responses cover the range of what political groups in the US have argued, I think. I don't think acknowledging reality on sea level dictates your response. It seems many, whether they agree with me or not on preferred response, disagree with that.
In any case, I don't think that we're going to be making good decisions for ourselves and our posterity if we ignore reality. It seems one motive for the unreal arguments and mandates is a desperate desire to get a particular result. It's the school of "The ends justify the means".
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Okay, different decisions for different circumstances. Beach resort properties obviously shouldn't be getting flood insurance supsidies. So, if Dauphin Island gets blown away every 20 years, that's okay so long as the wealthy don't mind doing their own rebuilding. OTOH the North Carolina outer banks are a more thorny issue. The road that runs up and down the thing probably can't be kept open much longer unless they rebuild the whole road up on pilings. Probably not economically feasible. So at some point they're going to have to decide to abandon the state highway and let those wealthy enough provide their own boat service, etc, again one hopes without subsidized flood insurance.
The hardest problem of course will be the cities. I am pretty sure there will come a time when New Orleans (full disclosure, that's me, two feet below sea level but protected for the time being so long as the Harvey Canal control structure is intact) and Norfolk VA and Miami become untenable. Some time between now and a hundred years from now this is really going to happen. We don't have a philosopher king that can decide to move whole cities. And in the case of New Orleans you have complications, there is a huge port facility, the intracoastal waterway intersects the Mississippi, there may actually be a reason to keep something here.
But if you really want to think big, it may be time to redesign all of southern Louisiana. The Mississippi wants to divert away from New Orleans anyway via the Atchafalaya, maybe the Corps of Engineering needs to start the redesign now and start transitioning vital facilities and population out of Orleans, Chalmette, and Plaquemines. Or, if you want to leave it to the Invisible Hand, start phasing out the flood insurance subsidies, and gradually make it more and more difficult to keep living here. Either way, not easy.
Good illustrations. I don't know which answers are best. As a general matter, it will probably be different answers in different places.
But I'm confident we'll get to better answers by considering our options and the different situations than by acting surprised that sea level is rising (and floods out those North Carolina areas that are pretending it doesn't) or pretending that the Gulf and Atlantic Coasts of the US don't get hurricanes.
One interesting model was developed to determine the economically efficient solutions along the entire US coastline in the face of sea level rise:
http://onlinelibrary.wiley.com/doi/10.1002/wcc.90/pdf
Caveats: The study assumes efficient behavior. The study does not take into account storm surge (which introduces stochastic behavior into the problem). The study accounts for local subsidence/uplift by assuming continuation at historical rates (probably good for most areas), but doesn't take into account any non-uniform global SLR (as in the "northeast hotspot" that made the news recently). Finally, the study does not discuss how to actually implement the efficient response, or how to distribute costs.
I agree with previous commenters that, based on my limited knowledge of such issues, our current flood insurance model is pretty warped.
-MMM
2nd independent thought: I think that rather than its approach of poking science in the eye with a sharp stick, if the North Carolina legislature didn't want to deal with adapting to 1 m of SLR, they could have tactically chosen to adopt the IPCC 2007 numbers, stating that "state policy shouldn't be based on individual scientific studies, but rather on broad scientific assessments", and there wouldn't have been nearly as much fuss.
(Personally, my gut instinct is for somewhere between half a meter and a meter globally. But since North Carolina has local subsidence, I think 1 meter is probably a pretty good assumption for long term planning).
-MMM
3rd thought: see this paper on rolling easements as one approach to dealing with rising sea levels:
http://water.epa.gov/type/oceb/cre/upload/rollingeasementsprimer.pdf
-MMM
I prefer first choosing my decision to fit my ideology, and then forming my reality to support that decision. Call it Decision Based Reality Making. :-)
Well, since this was posted we have had Sandy, further illustrating the need for clear thinking in the redevelopment of affected areas. Of less national attention has been the situation here in New Orleans. Traditionally we have been worried that the river would cut a channel to the Atchafalaya at a time of high water, leaving the city without fresh water, among other problems. But what we have now is the opposite problem- low river water secondary to the drought, resulting in the invasion of salt water up the river. Barges of fresh water have been going down to Plaquemines and an underwater dam has been put in the river to keep the salt water intrusion away from the water intake for Orleans. See: http://www.nola.com/environment/index.ssf/2012/12/underwater_dam_in_mississippi.html#incart_river
Anyway, it's sort of an interesting exercise in the various pressures climate change is exerting on infrastructure, at some point something is going to give, perhaps in an unexpected way.
Thank you for your invitation to pose questions and suggest topics here.
I would like to start by seeing if we're on the same page regarding SLR in recent times and what science can confidently claim about the near term future.
I am comfortable with the record of sea level rise being about 2mm/year until the mid-2000s, rising to 3mm/year for several years and more recently dropping back to 2mm/year.
Does that in your opinion capture the recent record accurately?
I am also quite comfortable with the IPCC's AR4 statement that projected SLR in this century would fall between 18 and 59 CM, not counting any contributions from dynamic movement of major ice caps. Again, does this accord with your understanding?
And then lastly, my takeaway from what I've read about such dynamic changes in the major ice masses has left me with the overwhelming impression that it would be very surprising to seem them occur in this century--and possibly in the next.
How well or poorly does this represent reality as you see it?
Thanks
Vigilius:
Absolutely. One issue is, you can't change just one thing. Perhaps the most substantial issue. New Orleans and the Mississippi River have an effective love/hate relationship. Trying to cure one thing which was hated, the flooding, has lead to problems with a different thing, which people are learning to hate, the sinking of the Mississippi Delta (leading to ... flooding. Now by way of storm surge.) When you have problems with processes which were already occurring, adding another uncontrolled change, by way of climate, almost certainly makes things worse. Hence the issues you name.
Tom:
I'll take up sea level in a full post in its own right. For the purposes here, the issue is merely that the politicians chose to ignore the science that the scientists they commissioned to study the issue came back with. Not because the politicians knew the science better, but because they didn't like the answers.
Your highly detailed time history for sea level rise (distinguishing between mid-2000s and more recent -- a total span of less than 10 years) points to an issue. 5 years is almost certainly not climate. I'll examine the data and show the results in the separate post.
A word choice, relevant to the point of this post. The North Carolina politicians were not comfortable with the scientific results. In the usual sense of the word 'comfortable', I'm quite uncomfortable with a lot of things regarding climate change. But, in the scientific sense -- does the science provide consistent support for a conclusion -- I'd have to say I'm comfortable with the conclusions regarding, say, sea ice and sea level.
Thank you Robert. I'll continue my questions when you post your sea level thoughts.
Robert,
See:
http://www.northjersey.com/news/Rebuild_vs_Retreat_Christie_and_Cuomo_offer_contrasting_plans_in_wake_of_Sandy.html
New Jersey says, rebuild in place. New York says, get out of Dodge. Perfect illustration for this post, I guess.
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