Do you want ice with that?

A popular pastime amongst those of us who have an interest in what's going on with the climate is to try to guess how much Arctic sea ice there will be each season when the annual minimum is reached.

For anyone reading who thinks this might interest them, there is an almost endless ongoing source of information, graphs and analysis at the excellent Arctic Sea Ice Blog/ Forum/Graphs.

There is also a science program which collects various predictions, from the technical (model-based) to the amateur (heuristic), called SIPN (used to be ARCUS).

Part of the fun of this is to try to work out the different factors which may or may not affect future sea ice level down the line. On a long time scale, this is easy enough, if you simply reference the climate data since 1979 and look at the history of decline in Summer sea ice levels. It is quite possible to do a 'rough fit' with historic data and come up with a prediction which is not far off the mark, though this is going to be more by chance than reason.

One of the most popular sources of data and information is the NSIDC dedicated sea ice and cryosphere pages. These focus on the measured data rather than prediction, but contain a wealth of useful graphics and links.

On the recent page you will notice a reference to a recent piece of research conducted by some of the members of the team, Serreze M. C. et. al., JGR (2016).

This paper demonstrates a connection which has an effect on the annual minimum:

"...They found that 68 percent of the variance in the date that ice retreats from the continental shelf break in the Chukchi Sea in spring can be explained by fluctuations in the April through June Bering Strait oceanic heat inflow..."


So, one way in which we can now make a more reliable prediction in relation to one part of the Arctic is in place.


Then, I noticed (not reported widely elsewhere yet) that others of the team have been involved in a different piece of research at the opposite side: Fram Strait sea ice export variability and September Arctic sea ice extent over the last 80 Years. (Smedrud et.al.). Here we find the useful:


"...Increased ice export during winter will generally result in new ice growth and contributes to thinning inside the Arctic Basin. Increased ice export during summer or spring will, in contrast, contribute directly to open water further north and a reduced summer sea ice extent through the ice–albedo feedback..."


and: "...We find a general moderate influence between export anomalies and the following September sea ice extent, explaining 18 % of the variance between 1935 and 2014, but with higher values since 2004...".


These two useful recent pieces of work add to our understanding of two of the mechanisms which contribute to Arctic Summer minima. They don't give the whole picture; the number and range of the variables are such that we don't have a full picture of all of the teleconnections or causes.


What we can do, though, is look at these two parameters and add some inferences to our other observations. If Fram export has been relatively high recently, then the September minimum is likely to be lower than the long term average. If Bering Sea heat input is higher than usual during the Spring, then the Septemberminimum is likely to be lower. 

If both cases occur simultaneously, it is reasonable to infer that there is a high likelihood of a reduced minimum, if the other other known variables (such as the Arctic oscillation - AO) do not contradict this, and if the historic patterns of weather and overall seasonal temperature anomalies are also in alignment.

This is an example of how ongoing scientific research and information collecting adds to our understanding of the ways in which the climate can vary, and the trends which show how the climate is changing relative to the past.

When will the Gulf Stream ‘shut down’ and how will it affect our part of the World?

Quick answer: It probably won’t shut down completely in the next century or two. It will almost certainly weaken progressively during the 21st century, and will have an effect on both UK climate and US sea level. 

 This means that the UK may experience an amount of cooling relative to the global average and the long-term local average, and the US Eastern seaboard may experience an amount of sea level rise greater than the global average and the local long-term average, both within this century.

In simple terms, even if the Gulf Stream does not shut down completely, the impact of a weakening of the system will be felt this century, and conceivably within the next 20-30 years. It has already been felt at least once (2009-2011), and the current CO2 concentration pathway suggests that this kind of thing can easily be repeated, is likely to be repeated.

Back in 2006 I spent some time trying to understand how the Gulf Stream worked and what the implications of climate changes would be for me, living in the UK. This included exchanging some emails with a few of the people who were active at the time in analysing the data and models, and a lot of reading.

In 2009, the UK Climate Impacts Programme (UKCIP09) published it conclusions about projected changes to the UK in the 21st century, which also leaned heavily on similar sources to infer likely scenarios for change to our climate.

Since that time, the issue has stayed in the scientific literature, and occasionally pops up as a matter of concern on the internet or in the media.

Most recently, the technically reliable RealClimate has drawn my attention again to the matter in a post: The Underestimated danger of a breakdown of the Gulf Stream System. 

This summarises a paper which draws attention to some of the limitations of the modelling of the Gulf Stream, or AMOC.

Whilst it is a very useful reference, including links to several recent developments in both analysis and modelling, it does not address a question which I raised in the comments section but have not yet had answered: When is this going to happen?

Even more recently, The open access Journal of Ocean Science has published a paper which, though it focuses on a different aspect (sea level rise), has a strong section on the AMOC and some interesting material on modelling: Changes in extreme regional sea level under global warming.

The Scripps paper (Wei Liu et. al.) applies a flux correction to better model the freshwater exchange in the system on which so much depends. It suggest that the Gulf Stream could lose about a third of its strength by 2100.

The Brunnabend et al  paper uses a reasonably new high resolution ocean model, POP, which is able to capture the mesoscale eddy formations in the north Atlantic and the impact this has on regional sea level rise. It also, as you might expect, provides a greater resolution for modelled AMOC flow under the scenarios used (RCP8.5). The model runs out to the end of this century, from an original baseline of 1950, and a comparison between the first and last twenty years of the model.

In that model: The maximum AMOC at 26◦ N decreases from about 20 Sv to about 5 Sv (red curve in Fig. 4a). The spatial pattern of the AMOC does not change, but the North Atlantic Deep Water shallows by about 1000m (Fig. 4b–c). The maximum strength of the AMOC at 35◦ S decreases (blue curve in Fig. 4a) by more than 60 %. The decline in the AMOC causes a rise in mean DSL of up to 0.4 m near the North American continent, mostly because of a redistribution of ocean mass towards these regions (see Fig. 1a).

*Note: Sv refers to Sverdrups: "...used almost exclusively in oceanography to measure the volumetric rate of transport of ocean currents..." This is derived from a model which assumes a high CO2 concentration pathway and associated global temperature change, so might be considered a ‘worst case’ result.

Where does this get us?

So far, I am at the stage where I’m reasonably confident that the Gulf Stream will demonstrate a severe case of Hiccups over the next 80 years, with has already begun. As in 2009-2010, there will be years when the current slows by 30% or more, resulting in seasons which are noticeably cooler than the long-term trend would otherwise suggest. 

This is the UKMO comment on the Winter of 2010, which followed the most recent hiccup:

The following represents an assessment of the weather experienced across the UK during winter 2009/10 (December 2009 to February 2010) and how it compares with the 1971 to 2000 average (the period used for the seasonal forecast). 
Mean temperatures over the UK were 2.0 °C below the 1971-2000 average during December, 2.4 °C below average during January and 1.6 °C below average during February. The UK mean temperature for the winter was 1.6 °C, which is 2.0 °C below average, making it the coldest winter since 1978/79 (1.2 °C). Over England and Wales it was also the coldest since 1978/79. Over Northern Ireland and Scotland, winter 2009/10 was comparable with 1978/79 and 1946/47, with only winter 1962/63 significantly colder in series from 1910. For northern Scotland, it was the coldest winter on record, with the highest number of frosts. A generally mild first 10 days in December was followed by a colder period. This cold spell persisted for the first half of January, with some severe frosts. After mid-month, temperatures rose to around normal before a return to colder conditions. These persisted for most of February, with only a few brief milder interludes mostly in the west and south.

For the sake of simplicity, I’ll assume that a slowdown of 30% roughly equals a drop in mean winter temperature of around 2 degrees. I am not aware of a similar ‘spike’ in the US Eastern Seaboard sea level and am interested to know if this has been researched.

This occasional and regional cooling has to be taken into the context of expected rises in global mean temperature (which will go on irrespective). As things stand, depending on the mitigation scenario, this is likely to mean a temperature rise of between 2 and 4 degrees out to 2100. Again, for simplicity, I’m going to use a median figure of 3c by 2100.

So, by about 2070, the cooling effect of the AMOC slowdown will be offset by the warming effect of the global mean, which at that stage would be between 1.5 and 2.5 degrees. This suggests that the UK will experience a number of cooler winters, comparable to 2010, for the next forty years. After that, its more likely that the cooler winters will be statistically more like recent seasonal averages, i.e., mild.

Meanwhile, back on the US Eastern seaboard, I am speculating that there is a chance that AMOC weakening events could enhance dynamic sea level rise and add 20-30 cm of extra level by the end of the century. This means that a rise of a metre in some areas is plausible by 2060-2070. Add the effect of storm surges and increased offshore cyclonic activity, and New York could experience ‘Sandy-type’ surges on several occasions, with the probability and frequency rising as time goes on.

This is a complex area of study and I have not really done it justice here; my hope is that the average lay person can get a bead on what a slowdown of the Gulf Stream actually means for us and our children.

It just seemed like the right thing to do

Back in the chain Gang

I've never exactly been a Player in the online climate science field, though have dribbled around the edges for some time and have occasionally received encouraging noises from scientists whose opinions I respect.

But in previous iterations, my blogs have received a few tens of thousands of readers, and, more recently, I have a steady readership when I post on Quora.

So, though it may be a small constituency, yet there may be some people who appreciate what I try to do online and it is for them, as well as myself, that I have decided to reopen the blog.

Why now? Mainly, because it feels as if Truth is under attack. Prejudice and dishonesty abounds and is sometimes rewarded. Decency is not in vogue, and being human matters less than being noisy/young/pretty/opinionated/a cat.

Which leads to my second reason: for some time I have been concerned that there is a moral issue in respect to climate science and future-casting in general which is being steadily eroded. And this issue is our treatment of, and respect for, each other as humans. 

Today is Holocaust Memorial Day. It exists because many people think it important to remember the evil which can and has been done in our names, or with our consent. It is important.

As I spend more time than is healthy considering, analysing and speculating about our collective future, I am reasonably confident that our society is changing, not for the better. There is an ongoing and future injustice which, if the projections play out, represents a human harm, a level of suffering, which is not just comparable to the suffering of the holocaust, but on a scale so vast as to be almost unthinkable.

Seventy five years ago, there were people who saw what was happening in Europe, in Nazi Germany and elsewhere, a more virulent continuation of historic persecutions going back centuries, and they turned away. Some did not.

And this is why I have returned. If a vast, unspeakable crime against humanity is to be committed, it will not be with my consent, not in my name, and I will not ignore it or simply let it happen. I am opening a dialogue to people who understand the stakes in climate, politics, environmental and social Justice and injustices, and who believe that such depravity should not go unchallenged.

All this is very serious, but please don't be put off - I'll still sometimes make a joke.

No news is not news, but nonetheless.

Picked up a short review on Newsnight this week, where Kirsty Wark praised Chris Rapley's new (ish) book, "2071, the world we'll leave our grandchildren". When I've read it you'll get my opinion, but on the surface it looks pretty decent.

One of the things which has been happening to me alongside the new job - yes, thanks, it's going okay - is a new 'way of living'. This hasn't been arbitrary. Having been less than ideally placed in the health department, early April saw a diagnosis of Type 2 diabetes and some fairly serious reevaluation of my circumstances, choices and wishes.

As a consequence, there has been a rediscovery of the joys of cycling, which anyone who keeps up with Annan & Hargreaves knows, is a bit lively round this neck of the woods. Which is to say, there aren't very many flat roads. Or, more accurately, there are no flat/level roads, just downhills or uphills, some more so than others.

Starting from a base of some past experience some years ago but not much in recent years, since work moved me off travelling to work by bike and on to travelling to visit clients by car, there was the mixed challenge of getting the bum-bones used to the idea of sitting on a saddle for more than a few minutes, getting the heart and lungs working beyond 'normal', and generally shifting far too much excess weight around one way or another.

So, here's the slightly bizarre parallel, and probably not very original. I have been self-indulgent, easy-living, comfortable but essentially not very healthy. A bit like Western (sic) society in modern times. As a consequence I got a few problems, which aren't the type which go away in a hurry, especially if they are ignored. So, for no better reason than it seemed the sensible thing to do, I have slightly adjusted little bits of my life habit to steadily modify the present effects of past indulgence, and to reduce the risk of future complications or, at worst, crises. Are you following so far?

So, the parallel is with the way as a society we tend to live in the world; comfortable, self-indulgent, unhealthy. The planet is showing the kind of symptoms and problems that indicate a long-term problem with both present and future issues, which won't be resolved by ignoring them. So, to make a difference to present and future circumstances, we could do worse than make some small, positive adjustments to the way in which we live in the world.

Is Carbon dioxide the Sugar of the Environment? There, that's the question. Your thoughts?

On notice

I've tried to sustain this blog for a while, feeling that there is still room for some odd thinking here and there, but events have conspired to make it rather more difficult in future.

In short, I'm starting a new job next week which is likely to demand a fair bit of my 'spare' time and a whole chunk of energy.

Luckily for the climate science debate, this isn't a significant contributor, my viewers are eclectic, if high quality (thanks, chaps), and  a lot of what I cover features elsewhere, with a slightly different slant.

Sometimes I pick up on things which seem to have gone under the radar, and I wish that a few more people had seen what I saw as significant, but readerships have a way of telling the story in their way, too.

I don't intend to abandon writing about climate and related issues, but it could be some weeks between messages (yes, real hiati) , but regulars have got used to that.

Its also highly likely that my regular appearances in the commentariat elsewhere will be curtailed.

Thank you for your support and patience. When it matters, I'll still be posting, especially after the General Election, where I have been supporting the Green Party and getting involved locally.

Fergus.

In defence of Tol, or not

This morning's exchange with Richard Tol at the Guardian allowed me the opportunity to raise a point which I think needs to be clear to people engaged in climate science discussions online: Tol is not a hardcore denialist.

Below is what has appeared so far. The point is Richard's central comment, divided into four parts: 

off topic, and in the public record
- climate is changing
- greenhouse gas emissions are a major cause
- climate change is, in the long-term, net harmful
- polarization a la Nuccitelli hampers climate policy

No problem with points one and two, and all those who love or hate RSJT on the basis that he is a denial monkey should read and digest.

Point three is of course a key matter and IMO worth engaging in discussions about. Where Tol sometimes seems to miss the point is that climate change is, ipso facto, a long-term problem (it may also be a short-term problem, but this is open to discussion, too). The point is that his qualifier 'in the long term' is redundant. There is a tendency for people to extrapolate from this idea that it is not a 'problem' in the short term, therefore it is not necessary to create mitigation policy now. To reach this conclusion is to fundamentally misunderstand the nature of the risks and problems which science has highlighted.

Which brings us to point four. Richard accuses Dana of polarising the issues and thereby obstructing policy. Anyone familiar with his track record will find this a most peculiar claim, since Tol has allowed those who wish to obstruct policy, notably the GWPF, a number of Tory MPs and people such as Matt Ridley to persistently misrepresent his work without correction, whilst at the same time offering self as critic to those, such as Cook and Nuccitelli, who are clear advocates of policy action.

I believe that Richard Tol believes himself to be a rational, impartial observer, but you have to judge a person (insofar as judgment is required) on what they do, not just on what they say. By this parameter, Tol has by default placed himself in the 'denial' camp. if this sits uncomfortably with him he must respond to it. By distancing himself from the people who misrepresent him to obstruct climate policy he can undo some of the harm already caused by these people. Should he feel no obligation or responsibility to so do, one feels inclined to presume that he is satisfied with this state of affairs, and by implication supportive of it. In which case he should stop whinging about the whole thing and accept that to many people he is a 'bad guy' and his actions (or inactions) prove him so.

Come on Richard, show your capacity for decency. There is a very important discussion of policy to be had and it could benefit from your input, but before that you need to detach yourself from your current reputation. Will you do that?

RichardSJTol 

54m ago

12

I particularly like the bit where Mr Nuccitelli tells Dr Spencer what Dr Spencer really thinks.

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  John Samuel  RichardSJTol 

  52m ago

  23

  I liked this bit. Gremlins.

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  JJRichardson  RichardSJTol 

  50m ago

  This comment was removed by a moderator because it didn't abide by our community standards. Replies may also be deleted. For more detail see our FAQs.
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  Fergus Brown  RichardSJTol 

  41m ago

  12

  I for one would be interested to hear from RSJT what RSJT actually thinks about whether the climate is changing and whether this represents a social risk.

  Well, Richard?

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  RichardSJTol  Fergus Brown 

  24m ago

  01

  off topic, and in the public record
  - climate is changing
  - greenhouse gas emissions are a major cause
  - climate change is, in the long-term, net harmful
  - polarization a la Nuccitelli hampers climate policy

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  John Samuel  RichardSJTol 

  22m ago

  01

  Polarization as in the anti-science promoted by the GWPF? Maybe the GWPF needs a scientific advisor.

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  Fergus Brown  RichardSJTol 

  14m ago

  12

  Kudos due for paying attention and bothering to respond. TY. I sort of know this anyway, really, because I've read your (available) papers. But people often misunderstand you - probably because you are as guilty as Dana of stirring things up, so I think the polarisation comment is a bit rich.
  I know many 'denial' commenters such as Ridley etc depend heavily on your work, especially as distorted by Lomborg via Copenhagen, but you never seem to spend time correcting their misunderstandings or inaccuracies. As a result, there's a tendency to place you one one side of 'the divide'. This may be unfair in your eyes, but it is perfectly understandable in mine.
  Polarization? Isn't that the bread and butter of journalism? I agree it can be frustrating, but via friends in the USA it is clear that there the discussions are not just polarised, they are politicised.

  
  

It's not us! New report casts doubt on Anthropogenic source of climate change!

Once the news gets out about the new paper published in the obscure but worthy Journal of Mythological Climate Studies there is going to be a lot of trouble.

The new report from academics in Iceland claims that humans are NOT the cause of climate change. After extensive research. they say, it has been established that Trolls are the principle source of the hot air - via CO2 and methane emissions.

Iceland has long included consideration for elves and trolls in its legislation, for example making sure that roads and other developments avoid certain stones and features in the local landscape which are said to be occupied by mythological beings: Guardian, 25/03/15 .

But the new research is truly unbelievable. "According to the data gathered," we were told by lead scientist Arne Illbebaackersson, "we have historically vastly underestimated the volume of emissions generated by Trolls and other quasi-human entities. Once these new estimates are incorporated into climate models the correlation becomes obvious."

Dr Illbebackerrsson's team has been collecting data from around elf-stones for more than a decade and their new paper shows the correlations in startling detail. Unfortunately, the article is paywalled so this blogger cannot provide a link.

Similar material published in nature and reported by well-known blogger Rabett (here) attributes the origins elsewhere, based on the same core evidence.

Famed climate scientist Michael Mann was unavailable for comment.