There’s been much talk in recent weeks about the 2degC global warming limit: agreed in Copenhagen, confirmed in Cancun. It has been questioned by many, including Kevin Anderson in a post on this blog, and by US Climate Envoy Todd Stern.
The scientists I’m working with in Doha, from the Climate Action Tracker, gave a press conference last Friday to outline what they think about this “goal” (I put it in quotes because I am a little tired of people saying it’s a “goal”. A goal is something you strive for, but personally I’d rather we didn’t reach it).
But despite what Kevin Anderson and others are saying, these guys, from Climate Analytics, the Pik Potsdam Institute and Ecofys, have done probably the most substantive data crunching and modeling on this issue, the most definitive to date on the subject. Indeed, they did the core work on UNEP’s three Emissions Gap reports.
Their topline is that physically, technically and economically, it’s absolutely feasible. And without having to jump through crazy CCS or bio-energy hoops or any other such negative emissions.
There are many scenarios that show that the order of magnitude of the cost of staying below 2°C can be less than 1% of global GDP, if the investments are spread over time. But this means starting now.
From today’s levels, emissions would have to drop 15% by 2020 to keep below 2degC temperature rise (well, to have a greater than 66% chance of doing that). “Coordinated early action.” We can do it without CCS but with a lot of energy efficiency.
The IEA’s “efficient world scenario” says we can do it and that we would be economically far better off – none of those costs of hideous climate impacts to deal with either. You know, those storms and extreme weather events that seem to cost us more each year.
The longer we wait the more expensive it gets. The problem is that there have been a number of statements here in Doha, including two press conferences from the US, where it’s clear that many don’t intend doing anything beyond their Copenhagen pledges until 2020.
The next global agreement on climate is expected to be done by 2015 and coming into force by 2020. This is the agreement that will have all the big emitters like China and India in it, and which Tim Groser tells us he will throw his weight into getting.
A matter of choices
The problem with this is that if we wait until we get to this magic 2020 date to take any more action beyond the current pledges, then it’s going to get pretty tricky to stay below 2degC.
It’s still possible, but that’s when our choices start to narrow. Big Time. If you don’t like nuclear energy: tough. If you don’t like Carbon Capture and Storage: tough. If you don’t like the idea of bio-energy on a massive scale: tough.
Because if we want to keep below 2degC, those are the types of technologies we’ll have to employ to stay there, if we do nothing more until 2020.
Clearly, we’re heading in the wrong direction, confirmed this week by the Global Carbon Project’s latest figures that show we’re continuing to average a 3% rise in global emissions each year.
These are the choices:
1. We could act now, stay below 2degC temp rise, deal with the inevitable impacts that we’ve already got coming, but spend the least amount of money.
2. We could wait til 2020 and face a nuclear waste and technofix nightmare (even more worrying if CCS continues to be the money-waster and not-quite-ready technology it is now). And still probably risk breaching 2degC.
3. We could continue with the political foot-dragging personified by Tim Groser: a 4degC world in 2100. That’s the world painted by the Climate Action Tracker team – whose Director, Bill Hare, was lead author for the World Bank 4degC report, out a couple of weeks ago. Here’s some of the highlighted impacts:
- A warming of 4°C or more by 2100 would correspond to a CO2 concentration above 800 ppm and an increase of about 150 percent in acidity of the ocean. At that rate, ocean acidification will rise at levels higher than ever known in Earth’s history, leading to regional extinction of entire coral reef ecosystems.
- New results suggest a rapidly rising risk of crop yield reductions as the world warms. Large negative effects have been observed at high and extreme temperatures in several regions including India, Africa, the United States, and Australia.
- Given the massive threat to the living conditions of mankind, there is no certainty that adaptation to a 4°C world is possible.
Cheery stuff.
Gareth tells me we’re not allowed to re-publish a New Yorker cartoon without paying out an awful lot of money, but here’s the link to it. The caption says it all:
“Yes, the planet got destroyed. But for a beautiful moment in time, we created a lot of value for shareholders.”
…which brings me to a natural segue to an update on our lovely Government in Doha.
They continue to be showered with awards. Five “fossil of the day” prizes so far. We’re even ahead of Canada in the Doha tally. Yesterday’s fossil was for “being worse than Canada.”
Greens MP Kennedy Graham, myself and seven NZ Youth delegates are the only Kiwis here. Kennedy and I agreed this morning that being from New Zealand in Doha means a lot of apologizing. Embarrassing. And more to come, by the sound of it.
Groser’s belligerent statements as he left the country for Doha at the weekend beggared belief. He said it was “time the developing countries got on the mitigation bus.” That would be the bus you just got off, Mr Groser.
My favourite cartoon this week is from the LATimes. To quote “Holy Crap! God gives you humans a planet to tend and you turn the oceans to acid! What have you got to say for yourselves?”
http://tinyurl.com/assvwsx
The thought that washed through my mind when thinking about acidic oceans is that apparently the clouds depend on the dimethyl sulphide produced by plankton to provide the nucleii for cloud droplets to form on. Acid oceans = no plankton = no DMS = a lot of extra water vapour in the air waiting for an explosive release. Could it change the dynamics of rain?
It’s scary! 150% increase in ocean pH will mean the end of more than just coral reefs, it’s bad news for all marine ecosystems.
Not only the marine ecosystems. A flipped ocean could spell doom for land dwellers as well due to the massive release of Hydrogen Sulfide into the Atmosphre: http://en.wikipedia.org/wiki/Anoxic_event
This is one reason why Geo-engineering (shading technologies) will not solve the crisis as it may perhaps mute warming but do nothing to prevent acidification and a possible collapse of ocean ecosystems contributing towards the next anoxic event.
Direct link for New Yorker cartoon.
you’re confusing me, Bill. It’s the same direct link.
Doh! Sorry – it was my scriptblocker that didn’t let me through to the correct slide from your original link – sorry; my mistake! 🙂
By the way, Cindy, that photo of the Sultan of Shite you tweeted really does take the biscuit… or has one choking on it, anyway! 😉
And now he’s been evicted. And lost his UN credentials. So he won’t be able to claim to be an author of AR5 then?
Has anyone ever witnessed a more striking and pathological need on the part of an individual to be the centre of attention?
And this is one of Denial’s leading lights… You really can tell a lot about a movement by the people it elevates to prominence.
Kevin Anderson made a few points I’d like to hear these scientists you are working with in Doha respond to.
Have them read Anderson’s Climate change going beyond dangerous – Brutal numbers and tenuous hope>/a>.
Instead of just asserting “we” can limit global warming to 2 degrees by applyiing 1% of GDP annually, how about detailed responses to points Anderson makes?
For instance, Anderson says it is “highly unlikely that global emission can peak as soon as 2015”. Since Doha negotiators are only aiming to have a treaty come into force by 2020 it seems they have accepted that it is impossible for global emissions to peak by 2020. But, let’s say the impossible is achieved and emissions peak by 2020. Anderson points out that if a 2020 peaking date is accepted, the “least demanding” set of assumptions allowing a 50:50 chance of limiting warming to 2 degrees C involves “10 per cent per year upon year from 2020 and continuing for around two decades. He points out such rates of emission reduction are “unprecedented”. Even when the Soviet Union collapsed it only “triggered 5% year on year reductions for about 10 years”, he says.
What do your Doha scientists say about this?
Anderson points out that the Stern report concludes that cuts in emissions greater than 1% per annum “have historically been associated only with economic recession or upheaval”.
He discusses what it means as the global emissions peaking date moves out toward 2020 and beyond and says “all” the analysis is based on assumptions “few, if any” analysts consider appropriate.
What about these analysts you are in touch with? Are they the types
Anderson says know exactly what he is talking about but who say nothing, or do they know his arguments and can confidently refute them?
Let them study what Anderson says, and refute him point by point.
He says bringing on massive amounts of whatever, i.e. nuclear, or carbon capture on fossil fuels, although required, “begs the question of how possible and likely it is that… [this] could be put in place fast enough”.
He’s saying the standard BS, i.e. what is in your post, “we” can do what is required for a paltry 1% of GDP, and all we have to do is start now, is preposterous.
“we have left it so late to respond that net costs are essentially meaningless”. “We live in a non-marginal world, where very large changes are already occurring, both in terms of impacts of a changing climate and of societal responses and stresses”. “neoclassical (market) economists continue to propose marginal-based theories of small changes, regardless of the scale of the problem; this is not only academically disingenuous but also dangerously misleading.”
hi David
will get a more detailed reply for you – might take a while: busy people.
Essentially, as I understand it, Anderson used the “least cost” reduction pathway models as opposed to all the full reduction pathways. And added his political opinion.
Once we get to 2020 it’s a heap of “ifs”. Including the big “if”, for example, around whether CCS will work and others such as “if” govts are prepared to shut down the newly-built coal-fired power stations that are on the planning books right now.
But if they were to start now they wouldn’t be building the new infrastructure on those planning books.
I too have been thinking about Anderson’s statements. The climate action group says that action must begin now. I get a sense from somewhere that the window in which a difference may be made is about 10 years but maybe others have been saying that. This is a carbon cliff. Climate action have done an analysis of Mexico and find their actions fall far short of their announced intentions and further Mexico say that the rest depends on financial aid. Here lies a problem of Kyoto. It is the only plan on the table, very fine in parts, but the sense of time to change things has created a gap wherein governments can keep shoving things into the future. So the “85%” that are not in Kyoto now have no plan and suppose wrongly that 2020 is soon enough to get round to one. Under Kyoto aid has been pledged to developing countries but never delivered except maybe in rather small ways. Nor will it ever be delivered because every country has more than it can cope with within its own boundaries – ongoing floods, storms and droughts are seeing to that quite apart from the instability of consumerist societies. China calls itself a developing country but is probably the only country with more money than it knows how to spend. That they want to take on the Canadian tar sands suggests that they are not serious about emissions either. David uses above the phrase “dangerously misleading”. Good intentions and unworkable ideas can be dangerously misleading.
I consider that the first thing in any program or plan to reduce GHG emissions, on the part of a government that says it is serious about mitigation, is a programe to keep the issue before the public, in climate understanding, in planning, action and reporting on action. That would be a test of seriousness in itself, visible to everyone. We know a lot more about the issues now. Does anyone know of any government led programs to keep people thinking about climate issues? A serious government might also treat wilful disinformation with respect to climate change issues in the same ways that misleading parliament, or misleading investors is treated. When it comes to money the law is sure -there can be no more important a prospectus than a plan to reduce emissions. But on keeping the people informed, it is that attention that creates momentum, secures cooperation, enables people to make their own choices, hard choices if necessary. I’ve found that laying everything on the table then inviting and enabling cooperation can get large jobs done cheaper, more effectively and with goodwill, whereas those who keeps things to a select few for fear of criticism or discovery manage very little and earn criticism.
Noel
Boy! You slobbered a bib-full there Noel! Good on yer, mate. May I plagiarise you if and when needed?
Wipes chin 🙂 Use what you like. Did you find the phrase “instabilities of consumerist societies” an extreme understatement?
However, I’ll take the opportunity to put another perspective. Soon after WWII a writer forcast that “right human relations” (whatever we think that might mean) would be the future idealism. He described the scope of this as right internal relations, right relations between people and right relations between humanity and all other lives. The last is what we are on about with climate change with the issues in the other areas getting in the way of right action.
Noel
What Anderson claims is that the Tyndall Centre examined the most widely accepted analyses of what could be done about climate and found them to be so flawed their conclusions, that sufficient action can be taken to stabilize climate while traditional levels of economic growth are maintained, cannot be and should not be part of the debate. This goes at least for the Stern Report, the UK Committee on Climate Change, and the EU’s adaptation and mitigation (ADAM) report, as he specifically names these.
As he often repeats the word “all” or “virtually all” when referring to such reports, if I had taken part in writing the Emissions Gap reports you mention I would be assuming Anderson was talking to me.
I don’t see where the politics is in what Anderson is saying. His call is for scientists to speak clearly to civilization about what the facts are.
When he states “virtually all mainstream analyses assume that emissions will grow by only 1-2 % per year before peaking”, and he states that “in reality emissions are growing nearer 3-5% per year and are set to continue”, there is no politics in what he is saying at all. He is either correct, or he isn’t.
When he points out that “almost all orthodox, low-carbon emission scenarios are premised on implicit assumptions about emission peaks from non-Annex I nations that few, if any, analysts consider appropriate”, I fail to see what is political about it. All the analysts either believe non-Annex I countries are going to do what the mainstream projections assume they must in order for the climate to be stabilized while prosperity is maintained in the developed world and extended to the entire human population, or they don’t.
Everyone involved in the negotiations at Doha might believe China and India are aiming or will aim to have their peak emission year in 2017 or 2018 or it may actually be the case that everyone actually believes something else. Everyone might believe that carbon emissions will grow in the future by 1-2% per year until the rate falls to zero by some date prior to 2020, or they don’t.
Anderson says Tyndall studied what what the mainstream reports say, found them detached from reality, and then studied what it means if things are actually not the way they are assumed to be in the reports.
When you write things like “There are many scenarios that show that the order of magnitude of the cost of staying below 2°C can be less than 1% of global GDP, if the investments are spread over time. But this means starting now, I suggest, if Anderson and Tyndall are correct, that this is like saying, after Hitler conquered France, that there are many scenarios that show that France can be successfully defended, if we start now”.
Anderson: “I think the climate scientific community has hugely underplayed the size of the problem, knowingly, because its very hard to come up and say what you really think, because people don’t want to hear the message”
When Anderson sums up where we are headed, i.e. 4 degrees, he says: “there is a widespread view that a 4 degrees C future is incompatible with any reasonable characterization of an organized, equitable and civilized global community. A 4 degrees C future is also beyond what many people think we can reasonably adapt to….. Beyond this, and perhaps even more alarmingly, there is a possibility that a 4 degree C world will not be stable, and that it might lead to a range of natural feedbacks, pushing the temperatures still higher”.
The concluding sentence of Beyond ‘dangerous’ climate change: emission scenarios for a new world:
“However, this paper is not intended as a message of futility, but rather a bare and perhaps brutal assessment of where our ‘rose-tinted’ and well intentioned (though ultimately ineffective) approach to climate change has brought us. Real hope and opportunity, if it is to arise at all, will do so from a raw and dispassionate assessment of the scale of the challenge faced by the global community. This paper is intended as a small contribution to such a vision and future of hope”.
Despite the unfortunate Godwinism, David Lewis has a point. But only that Anderson is saying that the emperor has no clothes.
Warning: if you reacted badly to Kevin Anderson’s blunt speech, you may wish to stop reading here.
A world that can “start now” is not the world that we live in. It’s a world in which Asian and African peasants have secure property rights and access to credit at fair interest rates, and their leaders want the best for all their people (not merely to stay in power and enrich their kin). Not our world.
Our world is also not a world that cares about coral reefs, or even the death of all vertebrates in the oceans. Sorry, but actions speak louder than words. Actions say that we don’t care whether fish survive the next century. That’s not a surprise when we don’t care about people.
What I would like to see, and what is suspiciously absent from the NGOs’ studies, is quantification of the social effects. Study after study spouts numbers about the physical effects under various scenarios–x degrees of temperature rise, y percent loss of corals, and so on–but when it comes to what that means for people, suddenly the numbers disappear. Instead, we get “large”, “massive”, etc. How large? How massive, exactly?
(We also get speculation, such as the “outpourings of H2S could kill all chordates” idea, presented as a definite possibility. As far as I know, this is one team’s postulated explanation for a large extinction event in the past. It doesn’t seem to be the accepted explanation for anything, and the evidence is not overwhelming. Saying “it’s going to happen” is just hysteria.)
What’s that–you don’t know the numbers for social impacts, and you can’t know them? Well, that’s what scenarios are for. The NGOs and institutes know how to do scenarios. Why aren’t they doing them?
One of the very few social-impact numbers I can find is a quote associated with Anderson himself: that it is “widely believed” that there will be “up to a billion deaths” from BAU climate change.
A billion deaths sounds bad (and it’s terrible for the victims and their families), but how bad is it in context? A billion deaths in the remaining 88 years to 2100 is just over 11 million per year on average.
According to the WHO’s “top ten causes of death” page (figures for 2007), 11 million is less than double the number of deaths from smoking, and less than double the combined number of deaths from heart disease, high blood pressure and road accidents–all things that we inflict on ourselves. Or again, less than double the total from diarrheal disease, mal- and under-nutrition, and respiratory disease: diseases caused by leaders’ callous unconcern for their people.
Also keep in mind that a steady-state population of eight billion with an average lifespan of 80 years will experience an average of 100 million deaths per year no matter what. An additional 11 million (or 22 million in some years) is bad, but given that it will be concentrated in areas where expected lifespan is already low and the death rate high, are we really going to notice? (I warned you to stop reading, didn’t I?)
And remember that “up to”. “Up to” a billion deaths. Up to.
Unless there is something a lot worse than just “less than a billion deaths this century”, the worst case scenario is something that we will hardly notice, cruel and selfish beings that we are.
Similar remarks apply to economic effects. We already accept and live with similar-sized We are now willingly reducing GDP growth by at least two percent–in poor countries through corruption and extortionary policies, in wealthy countries through preferring to believe a (false) morality tale of wicked debtors, victimised creditors, and just retribution instead of Economics 101. We–our leaders–really don’t care about a reduction in GDP from what it might have been in 2100.
So unless things are much worse than just a drop in the rate of growth, that means the world in 2100 will be only twice as rich as now, instead of five times–who cares? Not our leaders, that’s for sure.
So: what are the numbers? Where are the social scenarios? Exactly how bad can things get?
(Obviously in the “outpourings of H2S kill all chordates” scenario, they become infinitely bad. But what about other possible, and more likely, scenarios?)
Umm, I guessing you’re looking for an update to the IPCC Working Group II report?
http://www.ipcc.ch/publications_and_data/ar4/wg2/en/contents.html
Thank you for reminding me of AR4 WGII. Actually, the WGII report exactly typifies what I am talking about. The thing is a mess, endlessly rehearsing WG I type results and jumbling together physical effects, effects on ecosystems, and the various effects on humans.
Although it begins, in chapter 2, by briefly discussing the SRES scenario groups, the rest of chapter 2 and later chapters almost completely ignore them, preferring a completely unorganised presentation of the literature. Where numbers are given they are mostly for uncertainties rather than substantive results. Where substantive results are presented they are presented without context. (For example, a cost of $30 billion sounds dramatic and huge, but that sum is 0.2% of the present-day US economy, and less than 0.05% of the US economy in 2100 under standard assumptions.) The amount of weaselling and cavilling in the report is gargantuan.
To be fair, the working group is not responsible for the state of knowledge (although it could have and should have pressed researchers to use the SRES scenarios to structure their research), but it really, really needs to improve its presentation skills.
I really don’t want a repeat of AR4 WGII. I want something informative.
In our highly interdependent and just-in-time manufacturing society effects of major disruptions can be chaotic and are hard to put numbers on for sure.
A better indicator I think is a look through the history books and the analysis of collapse scenarios that did play out, despite the fact that the planet proper was still there, full of its resources.
It is the complexity of a culmination of rapid exhaustion of the “low hanging fruit” in many important resources – energy a central role here – and the ecological disasters that loom as a consequence of AGW that is most concerning.
I believe that putting our faith into “gradualism” (i.e. we will muddle through and if the fish run out we will switch to algae cakes…) is a dangerous illusion.
Unless we take possible conclusions such as the “outpourings of H2S kill all chordates” scenario seriously we will underestimate the severity of the situation we are walking into.
Even the fact that we are certainly currently triggering a major extinction event no less (even without any H2S) through our actions is horrendous and inaction indefensible.
4th IPCC report, see Wikipedia for a summary on the matter of extinction risks:
http://en.wikipedia.org/wiki/Extinction_risk_from_global_warming
I’ll drop this in here – I’ve just shunted a few $ to Avaaz to help them in their legal fight against Chinese corporations taking over a substantial portion of the Canadian tar-sands, then using GATT-style strategies to ensure they won’t have to face all the bothersome environmental regulations that are getting in the way of ‘native’ production. You may be interested.
Nothing to worry about folks – none of it is quantified properly, according to the “libertarian” smart aleck who regularly haunts the blogs in the mainstream media (last reply):
http://www.stuff.co.nz/national/politics/blogs/first-reading/7954334/Backtracks-on-climate-change-cause-little-heat
I note that he hasn’t the b***s to come on here and make his points.
I think Kevin Anderson is responding to a certain social and political framing commonly applied to climate change science.
I call this framing the “weak sustainability effects and mitigation” approach. Or; it’s just another “environmental issue”.
In New Zealand, this framing is typified by the Resource Management Act; the plan making and the resource consent approvals. I spent eight years in the 2000s observing this framing when I worked in resource management in Canterbury either for a certain decapitated regional council or as a consultant/contractor.
In this framing, environmental effects are always accompanied by the appropriate mitigation; and resource depletion is always within the politically sanctioned resource limit. So yes we can keep taking water from the Waimakariri River for irrigating dairy conversions on the thin sandy loam soils, as there is lots of “headroom” (in terms of ‘unallocated’ cubic metres per second of flow) before we hit the plan minimum flow for the Waimakariri.
We can see say the Stern Report in this light. Stern is interpreted as saying the “limit” for the carbon dioxide concentration in the atmosphere is 550ppm, when the actual concentration in 2005 was 380ppm. So there was lots of “headroom”. We could even keep on emitting for a long time. As there was plenty of time to reduce GHG emissions before we hit the “limit” The same (false) logic is applied to the 2 degrees C average global temperature change or to the “0.59m of sea level rise by 2100” interpretation of the IPCC 2007 AR4.
If you are conservative and business-oriented and wish to exploit natural resources for economic gain, then this framing is a natural fit as it justifies business-as-usual. You will probably unconsciously view environmental issues through your “effects are minor and mitigated and within the limits” spectacles.
If you are genuinely concerned about global warming, or the environment and consider the environment has intrinsic value, then you might end up adopting this framing as you think you need to target your message to the masses in the middle. You may even start calling the mitigation “green growth” and invoke the likely future economic benefits.
The problem is that the message of “real environmental problem but packaged with mitigation over time frame 2XX0” is heard by the other end of the spectrum as “just another environmental problem, yada-yada, still lots of time and headroom, techno-fix later”. Kevin Anderson’s point is that there has been NO SUCCESSFUL MITIGATION.
As an example Gareth noted that ‘New Zealand’s leading right wing blogger, National Party spinmeister and opinion poll guru David Farrar’ had a real hissy fit when he read that NZ scientists were giving estimates of sea level rise that differed from Farrar’s favoured rosy-tinted view.
Farrar said he had read the 2007 AR4 and understood that sea level rise was a real adverse effect of global warming. BUT (applying the framing) it would only be 59cm by 2100 at 450ppm CO2.. So the PR line to feed the National Party and his other PR clients was “59cm-by 2100-within-limits-no problems”.
So when the ANDRILL project found otherwise, he criticised the scientists for…well…contradicting his perceived “business-as-usual” framing of sea level rise.
One NZ politician who I thinks speaks consistently with the Kevin Anderson message is Kennedy Graham of the Greens. He gave an outstanding talk in Wellington after the Rio+20 conference about how Rio+20 represented a twin crisis; the environmental/geo/biophysical crisis of global warming and the international governance crisis of 20 plus years of the as yet unsuccessful UNFCCC process that culminated in Rio+20.
You can get some idea of his talk from this blog post and this post and this blog post, but without the passion he displayed in his talk.
Graham’s speech strongly showed up both the neophyte NZ Environment Minister Amy Adams (who was just embarrassing – repeating Tim Groser lines like “getting people on the mitigation bus” and Nick Smith lines like “the NZ delegation punched above their weight”) and the very boring and monotonous talk by Agenda 2021 and sustainability advocate Diana Shand (sorry Diana).
Oh well, a long comment in a post of long comments!
Indeed, many long comments.
@ gregvp
“what is suspiciously absent from the NGOs’ studies, is quantification of the social effects.”
Um. Let’s see.
1. The World Bank 4degC report covered social impacts, in a big way, from agriculture to disease and disruption of social systems and dis/re-location.
2. Then there’s the Dara Climate Vulnerability Monitor http://daraint.org/climate-vulnerability-monitor/climate-vulnerability-monitor-2012/report/
3. There’s also the Maplecroft Climate Change Vulnerability Index http://maplecroft.com/themes/cc/
sorry, don’t have time to do the proper html links, but i think you’ll find the figures in there.
Much appreciate your framing of the ‘framing’ Mr February. – Thoughtful discussion going on here. So as a friend of mine pointed out – clear vision needed. In many contexts I’m often reminded of that remark: “Where there is no vision the people perish.”
Noel
Regarding the framing by Mr February. A place where government climate change policy is hitting reality right now is the new expressway proposed between McKays Crossing and Pekapeka along the Kapiti Coast. This “Road of National Significance” will bring SH1 much closer to, if not into, the coastal zone, and into areas under 10 metres above sea level.
I recommend looking at this excellent summary of evidence from Martin Manning from Victoria University. He says you must plan for 1 metre SLR by 2100 at least – and that level might be reached sooner than that. His figures are not contested.
http://www.epa.govt.nz/Publications/04-12%20Martin%20Manning.pdf
He argues the expressway designers need to be sure they can deal with groundwater rise of 1 metre and associated flooding.
When he presented his evidence on Monday he also verbally added that ‘at grade’ ie local ground level roadway projects in the same area would really suffer under these conditions (the expressway is on a purpose built embankment).
A particularly chilling comment was that, at a mere 0.5 metre SLR some coastal areas can expect to experience a ‘100-year return event’ floods several times a year.
He also includes a graph reminding people that the 1 metre by 2100 is only a middle line projection. Another possibility is that we get to 0.9 by 2050.