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Tom and Emma are visiting today. They are our godchildren; nine year-old twins living in a developed, contemporary society with all its benefits and pitfalls. They are the subject of today’s post.

In 2048, Tom and Emma will be 50. They may have children of their own, or godchildren, or even grandchildren. What will their lives be like in that year? What sort of a life will they have had, and what hopes and fears will they have for their offspring?

In the most simple sense, this is the point of climate science; to offer us, now, a glimpse of the possibilities that exist for these children and, beyond them, their descendants. As such, it is one of a number of disciplines which aims to use current and past trends to point to likely future trends, and suggest a current ‘best action’ for a plausible ‘best future’.

But Tom and Emma aren’t the only people to concern climate science; beyond them, there are the many millions of children all around the world who are the subjects of the future. Then there is the other, nonhuman element of the world to consider; what can we expect for the ecosystems and species of animal and plant, for the wildernesses and cities? Who knows, even the old man might still be around in 2048. And climate science isn’t the only discipline which attempts to understand trends for the future; economics, politics, business, conflict studies; many areas of research have as at least one component a consideration of how things might look in the future.

But we all know that knowing what will be in the future is impossible. We are aware that, even in the most general sense, predicting how Tom and Emma’s lives will pan out is. strictly, pointless. The question is, whether we have yet reached a stage where the discipline of futurology has become scientific enough for us to be able to say, with any confidence, what sort of world they might be living in.

And this generalised, trend-based, ambiguous tomorrow is clearly dependent on a huge number of variables. One interesting question we might ask is whether the world’s timeline acts in a chaotic or a predictable manner. How much effect might a small development now have in forty years’ time? How much inertia is built into the global human system, such that any change is inevitably slow and thus trends are very reliable indicators? It is tempting to suggest that the future, especially as we deal further down the line, beyond a forty year horizon to a hundred, or two hundred years, may respond in both ways to change. Sometimes, small discoveries or ideas arrive in the right time and place, and their potential (for good or ill) is realised rapidly, the consequences felt nearly immediately and expanding as time passes. Other times, the behemoth that is human society rumbles so inexorably in a given direction that plans, however drastic, are doomed to failure because the machine cannot be stopped.

Beyond the matter of what sort of future is implied by current trends, there is the matter of what sort of systemic changes (should they be desired) will be achievable, by us and by them? This in turn might depend on what attitudes persist in society towards the problems facing society. And Tom and Emma’s attitude to their world will be shaped, at least in part, by what they learn from us.

What is becoming increasingly apparent, by whatever measure we use to ascertain the present and future state of things, is that the way in which we humans currently live in the world and interact with its natural components is not sustainable; it probably hasn’t been for fifty years or more, now. What is also apparent is that the trends in all disciplines point in similar directions into the future; towards breakdown, or collapse, of one element or more of our environment, security or (erstwhile) wealth. ‘Business As Usual’ is the currently common term to describe the path we are currently on. It is more or less certain that BAU is not a viable option for the sake of Tom and Emma, and even less so for their children. Whatever else has been argued or disputed in recent years, this conclusion seems pretty much rock solid. Which means, knowing the current way of doing things is inadequate, we need some guide as to what to do for the future, how to respond and what changes to make.

This, then, is the point of climate science. Yes, there are many, many elements which deal with this either indirectly or not at all; after all, there is a lot we don’t yet understand about the climate, especially on the global scales we deal with when considering climate change. But the value of climate science, economics, planning in all its many guises, lies in giving us a pointer, a guide, about what to do and how best to respond to the most likely changes. What we do in response to the information we have is critical. It is important for us, but for Tom and Emma, it is absolute essential that some changes in the way we live do happen. And these changes need to be powerful enough, collectively, to stop the juggernaut of BAU.

As I have said before, we can be either positive or negative about the future. It can be a shadow in which we see some inchoate terror, or a horizon beyond which lie all sorts of possibilities. Tom and Emma have the enthusiasm and optimism of youth on their side. They can develop an understanding of the world we live in based on what we have learned and what we already understand. But how they deal with this knowledge, what difference it makes to their lives and the lives of others, probably depends on something very fundamental, which is already forming within them; their ethics.

What is the point of climate science? One version would have it that is exists to save the world, to prevent destruction, and to avoid the dangers of the future. The other, that it is there to point us to the trail that leads to the pass in the mountains. And when we get to the mountain pass, and see what is laid out on the other side, we will know where we are going.

Here is a long post: I have taken a selection of extracts from the NSIDC press releases, going back to early August, to provide an overview of the season so far.

More remarkable, perhaps, is the figure from CT, regarding the number of days below 7 Mkm2 ice area this year; nearly twice the long-term average, and nearly three times the number compared to 1980.

NSIDC, 10th August:

July 2007 showed the most extreme ice-loss anomaly ever seen since the satellite record began in 1979, with a monthly average extent of only 8.1 million square kilometers (3.13 million square miles).

The absolute minimum usually occurs during the second week in September, but as of only August 9, sea ice has already sunk below that mile-marker. In fact, the daily extent fell below the long-term average absolute minimum back in mid-July.

Record rate of sea ice decline, July:

NSIDC, 17th August:

Yesterday and today, Arctic sea ice surpassed the previous single-day (absolute minimum) record for the lowest extent ever measured by satellite. Sea ice extent has fallen below the 2005 record low absolute minimum and is still melting. Sea ice extent is currently tracking at 5.26 million square kilometers (2.02 million square miles), just below the 2005 record absolute minimum of 5.32 million square kilometers (2.05 million square miles).

NSIDC, 4th September:

August in review

The low ice extent for August 2007 stands out sharply compared to all previous Augusts. The August 2007 monthly average extent was 5.32 million square kilometers (2.05 million square miles), falling well below August 2005 extent, which was 6.30 million square kilometers (2.42 million square miles). Additionally, August 2007 ice extent is 31% below the long-term average of 7.67 million square kilometers (2.95 million square miles).

Even more stunning is that the August 2007 monthly average is the lowest extent in the satellite record for any month, including any previous September, which is typically the lowest month each year. September 2005, the previous record, had a monthly mean extent of 5.56 million square kilometers (2.14 million square miles).

Current Sea Ice Conditions: September 9, 2007

Figure 1 provides the updated map of sea ice extent for September 9, 2007. Sea ice extent now stands at 4.24 million square kilometers (1.63 million square miles). The magenta line shows the median September monthly extent based on data from 1979 to 2000.

The Northwest Passage is still open. The Northeast Passage, along the coast of Siberia, is still closed by a narrow band of sea ice.

17th September:

Sea ice is still declining, although the rate is very slow at present. Sea ice extent at this time of year can vary from day to day, as regions within the Arctic have small episodes of melt, freeze, or wind movement of the ice, just before the strong autumn cooling. As of September 16, sea ice extent was 4.14 million square kilometers (1.59 million square miles), surpassing the previous one-day record of September 20–21, 2005, by more than 1.2 million square kilometers (461,000 square miles).

20th September:

The long-term average minimum, based on averaging data from 1979 to 2000, is 6.74 million square kilometers (2.60 million square miles) and occurs on September 12. Compared to this average, five-day mean ice extent for September 16, 2007, was lower by 2.61 million square kilometers (one million square miles), an area approximately equal to the size of Alaska and Texas combined, or the size of ten United Kingdoms.

The minimum for 2007 shatters the previous five-day minimum set on September 20–21, 2005, by 1.19 million square kilometers (460,000 square miles), roughly the size of Texas and California combined, or nearly five United Kingdoms.

Current sea ice conditions: October 17, 2007

Figure 1 provides an updated map of sea ice extent for October 16, 2007; the magenta line shows the median October monthly extent based on data from 1979 to 2000. Sea ice extent is 5.65 million square kilometers (2.18 million square miles), an increase of 1.52 million square kilometers (590,000 square miles) since we reached the minimum extent of 4.13 million square kilometers (1.59 million square miles) on September 16.

While sea ice is again growing, we didn’t actually get above the previous absolute minimum record extent, set on September 20–21, 2005, until October 14 of this year.

An astonishing figure from Cryosphere Today:

The number of days with sea ice area below 7 Million Km2 was 42 in 1980, and as low as 39 as recently as 1996. 2006 saw a record 89 days below 7.0 Mkm2. So far in 2007, (my estimate), we have had 110 days below this figure. We can expect another 30 days, give or take, perhaps 140 days.

The current areal anomaly is close to -3 Mkm2. The most recent figure (from Walt Meier) for extent anomaly was ‘close to’ -3 Mkm2, slightly up from the absolute limit around October 14th.



Currently a discussion paper at CPD, Etien et. al. is a new reconstruction, making use of several proxies, for Northern European Temperature since 1596. As well as providing a new dataset for intercomparison, the paper offers new insights into uncertainties, and suggests that its finding act as an independent validation of the Manley CET.

The paper is open access, available at the bottom of the page I have linked to. It contains a great deal of information which should be useful, so I won’t do it the disservice to trying to reduce it to a paragraph or two.

Why is it useful? It offers a reconstruction which is independent of the  previous work which has been criticised, for example, at Climate Audit. It also seems to demonstrate that the Manley CET is a reliable reconstruction, which is reassuring. There is an opportunity to compare this reconstruction with previous efforts (Mann, Briffa, Moberg, etc…) in graphic form in the later pages. It also concludes a clear warming of 0.8C over the instrumental period compared to pre-industrial averages, up to 2000.

Whilst it is possible that there are problems or errors which have yet to be picked up, this is clearly a substantial and carefully constructed piece of work, which could be a benchmark for future reconstructions, using as it does a variety of proxies and a clearly defined, uniform baseline dataset.

As ever, opinions and feedback are welcomed, but Please at least browse the paper first; it really is jam-packed.

This looks like bad news for the USA…

Current and future U.S. weather extremes and El Niño

Meehl GRL

…Future El Niño teleconnection patterns over the U.S. are projected to shift eastward and northward due in part to the different midlatitude base state atmospheric circulation in a warmer climate. Consequently, projections for the changes in the patterns of extremes over the U.S. during future El Niño events include: decreases of frost days over the southwestern U.S expand northward and eastward; increases in intense precipitation in the SW U.S. expands eastward and areas in the SE U.S. become stronger; and decreases of heat wave intensity over much of the southern tier of states turn to increases.

Whilst this at least is good news; at least some tundra types  should act as a carbon sink as conditions change in the far North; and remember, there’s a lot of tundra…

The exchange of carbon dioxide between wet arctic tundra and the atmosphere at the Lena River Delta, Northern Siberia

L. Kutzbach1,*, C. Wille1,*, and E.-M. Pfeiffer2

 The wet polygonal tundra of the Lena River Delta was observed to be a substantial CO2 sink with an accumulated net ecosystem CO2 exchange of −119 g m−2 over the summer and an estimated annual net ecosystem CO2 exchange of −71 g m−2.


 But some less good news for those guys who were trying to get funding to try geoengineering a solution by dumping millions of tons of iron into the oceans; it don’t work…

The impact on atmospheric CO2 of iron fertilization induced changes in the ocean’s biological pump

X. Jin1, N. Gruber2,3, H. Frenzel1, S. C. Doney4, and J. C. McWilliams3

 …Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean’s biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.


  And back to a popular subject here at the cave; how good are the models of the cryosphere?

Atmospheric forcing validation for modeling the central Arctic

Makshtas GRL.

…Our analysis shows an excellent agreement between observed and reanalysis sea level pressures and a relatively good correlation between observed and reanalysis surface winds. The observed temperature is in good agreement with reanalysis data only in winter. Specific air humidity and cloudiness are not reproduced well by reanalysis and are not recommended for model forcing. An example sensitivity study demonstrates that the equilibrium ice thickness obtained using NP forcing is two times thicker than using reanalysis forcing.

This is a disparate bunch of stuff which caught my attention as I trawled the net. They all have uses, though the US projections and the iron thing stand out. To readers, please note, an interesting but obscure paper is always a welcome thing here at the cave, especially if you understand its implications…

Is so much easier if you can take advantage of expert opinion. So I did some back-of-the-enveloping, then decided to ask someone who would know much more than me.

Who best to ask? WTF: I emailed Mark Serreze the following enquiry:

I have noticed that Bill Chapman’s site at CT/UIUC is currently showing a negative areal anomaly of more than -2.7 Million Km2, which as far as I can ascertain is the largest recorded anomaly for this metric in satellite records.

Can you tell me if the same is true for your method of calculating extent, i.e., if the present anomaly (for the past 5 days, for example) is now larger than it was during the week of minimum extent, Sept. 16th?…

…I am also curious to know how far you think the anomaly might go before next April; is there any chance we might see a total areal anomaly of -3.5Mkm2, or even more?

Never let it be said that scientists aren’t good, decent considerate folk. Heck, these guys have their jobs to do, as well as handle the press, and could do without dumb emails from the likes of the Old man. So I wasn’t surprised when Mark replied, though I was extra pleased by the bonus email from Walt Meier. Here are a couple of extracts from their replies:


… in terms of ANOMALIES, yes, I would not be surprised if we still had a record, both in terms of ice area and extent. Check our last posting, you will see that extent is still way below normal.

Walt: do you have the numbers handy in terms of current ice extent anomalies?

Ice extent and area are increasing only slowly this autumn, the reason being that there is still so much heat in the Arctic Ocean. Will anomalies grow through this winter? I just don’t know. However, the ice we have by April will likely be pretty thin, setting us up for another big loss next summer.

Mark C. Serreze

And Walt replied, too:

Hi Fergus,

Yes, we have been tracking the extent anomalies relative to the climatology (1979-2000) and indeed it did continue to grow well after the minimum extent was reached on Sept. 16.

In fact, it reached as much as -3.25 million sq km about a week ago. Since then it has moderated some, but it’s still nearly -3 million sq km.*

This isn’t too surprising. There was such a huge area that was ice-free, allowing the ocean to warm up. This means it’s going to take longer to cool to the freezing point allowing ice to form. I would expect that the anomaly magnitiude will decrease through the winter**, but may still stay larger than the previously anomalies of ~1 million sq km we’ve seen the past couple of years. Also, as Mark mentions below, if where there is ice, it will be thinner.


* a quick technical point; the numbers I use are for the CT ‘area’ metric, Walt’s are the NSIDC ‘extent’ anomaly numbers.

**walt emailed to mention the typo, where he put ‘summer’ rather than ‘winter’; it has now been adjusted.

So, the anomaly did increase after the minimum was reached, by both measures. CT is still going downwards, though this could change within a week; to answer a potential disagreement on the earlier thread, my ‘eye’ estimate reads the ‘tale of the tape’ showing an areal anomaly of -2.75 Mkm2 +/- 0.05.

From this, plus my unique method of pseudo-straight-line analysis, I will now estimate the forthcoming seasonal mean extents for Autumn (October-December) and Winter (January-March). This can be compared against the fourth of the top-line graphs at CT – the one with the pretty colours.

The OND mean extent will probably not exceed 10Mkm2, and is more likely to be as low as 9.3Mkm2, +/- 0.2.

JFM should be below 13.5; my guess is 12.8 Mkm2 +/- 0.4. The mean annual extent, calculated at the end of Autumn, will be below 11 Mkm2, perhaps as low as 10.2.

I couldn’t work out how to estimate the Spring mean.

This sets the scene nicely for the bets between William, Eli and the others over at Stoat, for next Summer’s minimum. There is a very good chance that the maximum in March will be down by more than 1 Mkm2, and it could be as much as 1.5. The ice in April will be thin, and will melt or dissipate more rapidly as a result. Next year’s minimum might be very close to this year’s all-time record decline. I don’t know which side of the line it will fall, but I’ll hazard that it will be considerably lower than the 2005 (former) record minimum.

If anyone thinks my estimates are likely to be out by more than 1 Mkm2 either way, I’m willing to consider a small wager…

My sincere thanks go to Mark and Walt, and the excellent people who work at both the NSIDC and the UIUC to produce the data; you’re all heroes.


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October 2007