Some all-time temperature highs have been broken around Queensland in recent days with summer seemingly arriving while we are still officially in winter and my daily check of the temperatures in selected overseas cities last week showed Frankfurt at 36C, which seems rather high, so I was reminded of a recent Guardian article about a study predicting that the world faces record high temperatures over the next five years. Nothing too dramatic, just 0.15C, after which the warming should slow down again.
The work is the first to assess the combined impact on global temperature of four factors: human influences such as CO2 and aerosol emissions; heating from the sun; volcanic activity and the El Niño southern oscillation, the phenomenon by which the Pacific Ocean flips between warmer and cooler states every few years.
The analysis shows the relative stability in global temperatures in the last seven years is explained primarily by the decline in incoming sunlight associated with the downward phase of the 11-year solar cycle, together with a lack of strong El Niño events. These trends have masked the warming caused by CO2 and other greenhouse gases.
The muted influence of El Niño over the past decade can be clearly seen in this image:
Figure 1: Multivariate ENSO index
The Guardian article carries a temperature graph from the Hadley series. I prefer the NASA GISS version, because unlike Hadley it incorporates an estimate of Arctic warming, which has been very significant.
Figure 2: Global land-ocean surface temperature
In the NASA GISS series 2005 was the warmest year, with 2007 and 1998 equal second. This image shows where in the world it has been warmer and cooler in 2009 to date, 2005 and 2007. The bottom right shows an uptick in the past few months:
Figure 3: Comparison of 2009 Temperature to the Two Years with the Warmest Annual Means
Nothing is certain, of course. The study authors indicate that much depends on the ENSO pattern and whether there is a large volcano eruption or two.
Just to make things interesting a team led by Noel Keenlyside in Kiel and Hamburg suggested last year that there may be no increase in the next 10 years. According to the BBC report:
The key to the new prediction is the natural cycle of ocean temperatures called the Atlantic Multidecadal Oscillation (AMO), which is closely related to the warm currents that bring heat from the tropics to the shores of Europe.
The cause of the oscillation is not well understood, but the cycle appears to come round about every 60 to 70 years.
It may partly explain why temperatures rose in the early years of the last century before beginning to cool in the 1940s.
“One message from our study is that in the short term, you can see changes in the global mean temperature that you might not expect given the reports of the Intergovernmental Panel on Climate Change (IPCC),” said Noel Keenlyside from the Leibniz Institute of Marine Sciences at Kiel University.
But:
“In the long term, radiative forcing (the Earth’s energy balance) dominates. But it’s important for policymakers to realise the pattern,” he told BBC News.
However according to this New Scientist article behind the paywall, Gavin Schmidt and others blogging on RealClimate reckoned they got their data input into their model wrong and “offered the Keenlyside team a bet of €2500 that the average surface temperatures for 2005 to 2015 will, contrary to the team’s forecast, turn out be higher than during 1994 to 2004.”
The Keenlyside mob have not accepted the bet. According to Schmidt an co:
The issue is where the models start from. If you’re trying to forecast natural variability, conditions in the seas in the model must match those in the real world. Thanks to a network of undersea sensors, we are now starting to get good data on both temperature and salinity levels in the crucial upper layers of the Atlantic. However, feeding this information into models is not as easy as it might seem and – unlike Smith’s team – the Keenlyside team put only sea surface temperatures into their model.
“If you match the sea surface temperatures but not the salinity values, the water density will be completely wrong,” says Schmidt. Yet this density is crucial for determining the state of the thermohaline circulation and hence the AMO.
Meanwhile 90% of the additional heat from global warming actually goes into the ocean and only 3% warms the atmosphere. If you want evidence, look at what is happening with sea level rise:
Figure 4: Contributors to sea level rise
Follow the orange and especially the red lines. The heat goes in and the water expands. Please note, Senator Fielding.
But in terms of predicting, remember that the oceans cover 71% of the earth’s surface, are on the average 3.6 km deep and that it’s cold down there. At this stage it seems we simply don’t know enough to predict changes in currents and hence heat transport around the globe. And the oceans drive the weather. So short-term predictions are hazardous, but in the longer run surface temperatures will respond to changes in the trace gases in the atmosphere. The greenhouse effect hasn’t been cancelled.
It’s a bit pathetic and not very good for science if every time there is a minor dispute, it comes down to monetary wagers as to who is correct. Didn’t think science was supposed to progress this way…
Politically I would hate for there to be a cool spell driven by other (non-ACC) factors over the next decade – this would disastrously play into the hands of the fools in charge. And then rebound in spades later in the decade, when it’s already really too late.
Still, I’ve been singing this a lot recently.
I didn’t react much to the wager thing, wilful, except as a sign that the RealClimate mob were fairly sure of themselves.
A repeat of the pattern we had from about 1945 to 1975 would be nice and see me off the planet, but I agree that it wouldn’t necessarily be the best for policy development longer term. Speaking of which the currently anticipated El Niño mightn’t go amiss in relation to the UN Copenhagen climate talks in December.
This is a timely post, been watching the Multivariate ENSO for a few years now, maybe it’s just the hair-shirt greenie in me but I can’t help thinking that we’re in for a “correction” after the relatively subdued oscillations of the last decade or so. Can’t expect Mother Nature to stay quiet with all that extra energy being pumped in.
Reckon we should add another variant to the data though, the “denier activity index”, ’cause those guys are more cleverer than the rest of us.
Brian.
(I love Queensland in the winter, but have never been able to bear the summers, and I spent over a year there in the mid 60s.)
I think I might have made this observation on another thread some time ago, and its purely anecdotal.
Here in New England, (at least around Armidale, for at least the past ten or fifteen years the winters have been getting progressively shorter and, comparatively, warmer, and the summers are now so stinking hot its almost unbearable. One might as well go live in Queensland come summertime.
To my ancient mind the change in climate over the past fifteen years or so is definite proof of global warming.
On the anecdote line, Melbourne had its hottest recorded August night-time minimum this year.
Bring back Neil Diamond!
“The study authors indicate that much depends on the ENSO pattern…”
Speaking of which, looking at that first graph of Multivariate ENSO Index, does anyone else see a change in the FREQUENCY of ENSO indicators for El Nino versus La Nina, from about 1977?
It seems to me that after 1977, you get more frequent red and less frequent blue. Relatively speaking, could you say that for the last 3 decades we have been getting more El Nino than La Nina conditions? Compared with 3 decades ago, when we were all young?
That trend wouldn’t bode well for the future of the Murray-Darling, I presume?
Another anecdote: last Thursday I was in the Netherlands where it was 27C. Locals said the summers were getting warmer and therefor more Dutch were staying in Netherlands for holidays rather than going to Thailand, Spain etc as is traditional. However it may also be a result of the GFC.
Another great post Brian. I went to a presentation by Prof. Matthew England yesterday and he said that a number a scientist have challenged the deniers to a bet (their houses) that there will be marked increase of temperature over the next 10-15 years.
He notes that no-one has taken up this offer.
http://web.maths.unsw.edu.au/~matthew/
Looking at the graph of contributors to sea level rise, it seems that we have a linear increase for the yellow and pale blue lines, and a wonky essentially constant average on the green line.
Human beings seem to be reasonably good at adjusting to slow incremental increases, as per the yellow and pale blue lines, because they can look at the trend in the rear view mirror and make incremental adjustments.
The more worrying lines are the dark blue and red lines (glaciers, ice caps and the surface waters of the oceans). These lines are not a constant change with time, but look more like an ACCELERATING change – the slope of the line is increasing with time.
Studies have shown that human beings are dead lousy at coping with accelerating change. The psychologists say that we tend to subconsciously extrapolate linearly, even when we are told that it is an accelerating change. As a consequence, we tend to under-react until it is too late.
We can only pray that it isn’t an accelerating change, because we don’t seem to be able to move our economy at more than glacial speed. The way things are going, perhaps that will become a redundant expression?
Brisbane peaked at 32.2 degrees C today, 35.4 at Archerfield in the southern suburbs and 36.4 at Amberley near Ipswich out west. Just sayin’
Paul Norton @10, speaking of living in Brisbane, have you seen the Flood Maps for rises in mean sea level?
http://flood.firetree.net/?ll=-27.8390,138.1640&z=13&m=7
You can zoom right in to your suburb and even street, to see if the rising sea level will mean that you need to tether your tinny to the back door. Pick whichever sea level you think is relevant – 1 m commonly discussed, or up to 14 m if both polar regions melt.
Check out Brisbane airport and the Gold Coast – more than 1 m and they will become mozzie-infested swamps!!!
If you are feeling adventurous, then check out Bangladesh. Estimated population 142 million…and we thought we had problems already with boat people???
Elise #6,
there was a change in ENSO characteristics in 1976. We switched into an El Nino-dominated period. The Tahita Darwin pressure index stepped up (1 in 7 chance of being random). Interestingly it is also when the current warming phase started. Note that the current phase of ENSO related variability is uncertain (post 1999).
There is both natural variability and anthropogenic change in the phenomena that Brian posted, but no-one is able to weight their significance with regard to each other. The global warming phase post 1976 is likely to be dominated by anthropogenic factors but these changes will be overprinted by variability at regional scales.
SE Australia stepped up in max temp in 1998, stepped down in rainfall. At the moment causes can only be inferred but I’d be willing to bet there’s a strong anthropogenic influence in what’s going on at the regional scale.
Roger Jones @12, thanks Roger, I thought it looked like a significant change in the pattern.
The implications of this for Aussie farmers, and our agricultural sector generally, won’t be encouraging?
Elise @ 11, I did that once and the sea at 14m comes into the other end of my suburb (Ashgrove).
Paul @ 10, it’s hot, but I gather in Brisbane we missed the all-time record (1946) by a smidgeon. It’s more than 10C above average, though.
Eat the Rich @ 8, thanks and thanks for the link to Prof England. He’s got some interesting stuff under “Publications”.
Elise @ 6, said Prof England was involved in an interesting bit of research which links the Indian Ocean Dipole (IOD) to the big dry in the “south-east” rather than the ENSO. In short they reckon we’ve been lacking negative IODs, which are associated with increased rainfall. The positive IODs are really bad news, but even worse when they coincide with El Ninos.
But there are a few caveats.
The first is that the definition of SE means Victoria and points south and west. I think the El Nino is much more strongly associated with the NE of the continent and to some extent the east.
The second is that the Murray-Darling basin I think gets over 60% of its water from Victoria, much from the Alps. Only 5% comes from Qld, the rest from NSW and the ACT. (So Cubby station had bugger-all to do with the MD as a whole.)
The third is the ENSO and IOD are not the only things going on, so the full story is complicated and I’d very soon get out of my depth.
I’ll come back on sea level rise later.
I’ll echo what Eat the Rich#8 said top post Brian – I also caught Prof. England’s talk yesterday – he was very good, very well spoken.
(There were just 2 nutter questions which he handled calmly and in a friendly manner – 1st was a long speech type question that turned out to be co2-lags-temp paleo climate chestnut. The 2nd was (introduced himself as an engineer, you know this going to go bad – I’m a bloody engineer, when did so many of my fellow engineers become science haters) the models all wrong because the artic melt is actually worse than predicted thus models are wrong and there’s another cause besides co2 emissions. Both answered very well. Besides thos 2, everybody else there seemed to appreciate and learn from the presentation as I did. – so glad I went – I was up in the big smoke as the missus is culturing me, we saw Beethoven’s Fidelio, yeah yeah, that was nice too
@#5: Forget Neil Diamond, go Billy: http://www.youtube.com/watch?v=_brVtFvZQfw
Brian @14, we are in trouble here at about 3m rise. Tinny parked outside our back door, complete with natty little life jacket for the dog!
More seriously, sections of the Kwinana Freeway (including the new light-rail connection to Mandurah), parts of Riverside Drive and Mounts Bay Road will go under @ 1m or so, severely limiting access to the CBD. Traffic chaos if nothing is done in the meantime.
Hope the town planners, here and in Brisbane, are giving the matter serious thought for the future? It could be an expensive business trying to relocate major infrastructure, or alternatively trying build long dykes everywhere as in Holland?
Since Perth is built on sand in many places, shoreline erosion and embankment undercutting from erosion could be a problem?
And Hobart airport – looks like they will have to pick it up and move it.
SC @16
Was I too young when that first came out (pun intended) to notice its campy charm?
Booleanbach @18, also most of historic charming Busselton (WA South West coast) including the regional hospital.
They could up stakes and move the town inland, back behind the highway, but I wouldn’t want to be a home owner at the time.
Puts a new meaning on “sunk costs”.
Some August records broken today in the northern rivers of NSW:
Ballina: 36.2
Evans Head: 37.4
Lismore: 36.2
That broke previous August records for Ballina and Evans Head by a good 5 degrees. 5 degrees!
My Dad works at the W.A. Dept of Agriculture and he reckons that something is going on but the specifics of what is going to happen is another story.
He says that it is like buying insurance because at this point in time no one really knows for sure how many feedback and counterfeedback mechanisms are going to come into play.
Dr David Mills from AUSRA is on the internet saying things like 440ppm is unachievable, btw!
5 degrees, whoah: I would like to know why this is insignificant and I expect the papers will be tellling me one way or the other over the coming days!
Actually on the TV tonight I think they gave the Brisbane max as 35.4 as against the record of 32.8. The max wasn’t reached until after 4pm which means the sea breeze failed.
We’ve had 2.8mm of rain this month so far against decile 5 of 29.5mm.
Actually ABC TV News reported the top temp at Evans Head as 38 degrees and weatherzone agrees. According to weatherzone the top temps today were:
Ballina: 37
Evans Head: 38
Lismore: 37
Elise, on sea level rise the article I linked to is, I think, a pretty fair summary, but some of the numbers are different from what I found last September although it is drawing from pretty much the same literature. Back then we were told that thermal expansion by 2100 could be as much as 30cm and glaciers and ice caps, if they all go, 55cm. That leaves Greenland and Antarctica, which led me to believe that 2 metres was not unreasonable if we keep pushing things hard under BAU.
Since then we (or I) have learnt that West Antarctica has collapsed and regrown 60 times in the last 3 million years with CO2 levels no higher than they are roughly now and that the sea level rise could be higher in some parts of the world, notably the Pacific and the Atlantic coasts of the US.
That was meant to be because of changes in the earth’s gravitation, but a meltwater pulse from Greenland or Antarctica is thought to take 50 years or more to have much impact on the other side of the equator (see Figure 16 in this post.)
Things will no doubt proceed in a reasonably linear fashion for quite a while but if either or both of the aforementioned ice sheets comes seriously into play then the pact could quicken. I believe that net ice loss from West Antarctica is increasing faster than from Greenland. If the giant Ronne and Ross ice sheets start to destabilise then hang onto your hat.
Meanwhile the bigger worry apart from certain low lying parts and islands could come from storm surges. I repeat again a quote provided by Barry Brook on an earlier thread:
Mr.Burns makes me laugh,I wore a beanie last year all the way through to November,I admit today was hot being in Coffs Harbour.Even people in the Happy Frog were concerned it seemed a Fire Brigade type of day.Getting back up here to the T..ham smoke everywhere.The smell has dissipated a bit now.Like a Japanese Soldier or two after the second World War had ended,I will continue to say,however the world is getting cooler,and maybe ,the seasonal matter now is again,the problem of the soil types in Australia being excessively hard,from years of drought,and rains that do not soften the material greatly.As I travelled from North Dorrigo towards Bostobrick where the hills have the combination of winter drought look and summer dryness,near the Little Murray River,I concluded the loss of trees across some of the shape of the Geological forming was allowing a continuous drying.It would be interesting to see if the grasses are losing protein matter year in year out.Wind plays across shapes in its ow ways and will increase the likelihood of temperature increase,if there isn’t stiff resistance to it by clumps of older trees.Where I am talking about,the wind in and of hotter days will without any form of resistance go down into the depths of the valley and up at a constant or increasing temperature.It would be interesting to have something spinning and large in the depths of those geological formings.Or even a series of walls of strawbale rendered across shapeings in decline.To claim all matters in relationship to earth based warming like it is a series of steps has no real steppes in the Australian Landscape..just previous works done,which may need further work.
The author of the article above seems to be an intelligent, reasonably informed fellow who’s been following the science of global warming for some time.
What’s perplexing to me is how the author, and the authors of countless similar articles, could be familiar enough with the subject to post NASA GISS data, but have seemingly no awareness whatsoever of recent, pivotal studies which have completely and irrefutably disproved virtually every premise of global warming theory?
I highly recommend the following report by Christopher Monckton. It is an excellent summary of the evidence:
http://scienceandpublicpolicy.org/images/stories/papers/originals/co2_report_july_09.pdf
“A reasonable man, when presented with facts in evidence proving a previously-held belief to be false, will acknowledge the truth and discard his previously-held belief. Into which category do you fall?”
Whatever!
LOL@Monckton
Also LOLing @Monckton. Not referring to is not the same as unaware, “a”.
#28…”pivotal studies” as in ‘spinning madly in a deepening hole’…
“completely and irrefutably disproved virtually every premise of global warming theory”
Hooray! The laws of chemistry and physics have been overturned! Rejoice!
Now if only we could crack the great cabal of scientists and their evil peer-review process.
Booo hiss! As my geography lecturer used to rant on a regular basis*, weather isn’t climate. Climate change is certainly a reality, but you can’t guage its progress on local, short-term vagaries of temperature and rainfall.
*his hate-on for John Schluter was pretty hilarious.
I have to confess that I only skimmed the referenced article – the Guardian is a turgid read at the best of times, and this subject is usually far from its best of times – but the sentence “The world faces record-breaking temperatures as the sun’s activity increases” sprang out.
Haven’t we always been told that anyone trying to explain global warming in terms of the sun’s activity should be shot at dawn; the science is in and fossilised, and it is teh evil CO2 which is wholly responsible?
Besides, as you point out Brian, it is only a year ago that we were being told that warming is likely to take snooze for the next few years, not accelerate. I will keep my own wager in my wallet for a couple of months; the Melbourne Cup is far more predictable than the twists and turns of settled climate science.
As for those who are seizing the chance to parade the temperature yesterday at Ballywopwop as the clincher for imminent global incineration, well, it’s probably a good thing that Grumphy has already already said it since I would have been a good deal more snarky.
I think perhaps my snark was understated, given that I recall comments on this site lampooning conservative blogs/bloggers for doing the same thing but backwards when cold weather occurred.
Or maybe that was on pandagon. My robot brain needs caffeine.
Brian @26, thanks for the extra info. I’m not sure about 2m being the upper limit though, if the icecaps melt. Do you discount sources like the US Geological Survey (USGS)? http://pubs.usgs.gov/fs/fs2-00/
Admittedly I was thinking of “only” the Greenland and West Antarctic icesheets, with the 14m prediction. The USGS adds another about 65m if the East Antarctic icesheet melts also.
Apart from trying to calculate the level from thickness of ice and areal cover, we could consider the geological evidence from prehistoric times. My understanding was that the sea level in geological time, during periods of higher temperatures and less ice cover, has been a lot higher than 2m above current levels.
Our “massive sulphide” mineral deposits (copper, lead, zinc, etc) were laid down UNDER WATER, which is why they didn’t oxidise, and stayed as sulphides. Guess what? Those deposits are located on dry land now.
Our coastal cities in many parts of the world are built on sand and shale – they are former beaches and mudflats, and former river deltas. The sea level has obviously been much higher at some stage, when these beaches were formed. Encouraging news, hey, that the sand gropers have been more-or-less building their houses on the beach?
As long as we don’t go past the tipping point, where we get rapidly accelerating change, then perhaps the maximum sea level rise will remain a moot point?
Those coastal deposits (Qa and similar on geological mapping) are pretty much all Holocene deposits, Elise, so from the last ten thousand years or so – before that the SL was much lower due to a period of glaciation, where big chunks of the now-settled globe were under miles of ice.
Anyway, current data indicates that the sealevel has veered up and down slowly over that last 10k years, between -0.3 or so to a highstand of about +1 to +1.5 ~6000 years ago. That’s not a “huge” difference, but it was enough to create layers of marine sediment along the coast, much of which is now covered by more recent terrestrial deposits. And yes, things might get tricky for coastal construction in the next century or so, but at least the acid sulfates will be harder to disturb
Brian @24, reflecting on the trend of decreasing frequency of blue in the ENSO Multivariate Index (implying longer dry spells without a good soaking La Nina), and your comment: “We’ve had 2.8mm of rain this month so far against decile 5 of 29.5mm.”
It would now seem clearly apparent that we will have to build increasing numbers of desal plants for all major Australian cities, especially on the east coast?
Perhaps we will see the day when building regulations require gardens to be watered ONLY from household greywater, coupled with rainwater from household tanks – what rainwater is available that is…?
It would make sense if we all got around to reusing greywater (e.g. from handbasins and showers) since the average household uses as much water on the garden as on the house, most of it only lightly used before going down the drain. We would probably need to have more garden-friendly soaps, shampoos and detergents, if this were the case?
Up to 32.9 degrees in Brisbane just before 1pm today, and the wind is still coming in from the west.
Elise, I looked at those maps and found that even on a 14 metre sea level increase, my humble abode stays above water. Regrettably, my favourite holiday destinations don’t.
Paul Norton @40: “I looked at those maps and found that even on a 14 metre sea level increase, my humble abode stays above water.”
Are you planning ahead for space to accomodate all the Brisbane refugees from lower in the valleys?
I, for one, am designing a balcony-mounted, solar powered laser to fend off the moneyed hordes fleeing their canal estate “investments”.
There can be little doubt of Anthropogenic Global Warming (APG), but it is not wise to emphasise short term trends like warmer temperatures – short term trends are a technique that deniers use to hide the truth.
I live in Melbourne so of particular concern to me is the longest, driest and hottest period in the temperature record – now almost 13 years. Although the Indian Ocean Dipole (IOD) might have a role it is has been argued that its effect has been to decrease spring precipitation in the last three years. I have been following the work of Dr Bertrand Timbal who makes a strong argument that the decline in Southern Australian ranifall is related to increased atmospheric pressure. This is likely caused by the intensification of the subtropical ridge.
He will soon publish a paper directly attributing the southern Australian “drought” to APG. An article describing the new study is found at this link .
Quite right Steve – a point I’ve made myself in my more serious moments. The banter between Brian and myself (and others) in the comment about the current unseasonal Brisbane weather should be seen as just that, rather than a serious argument.
yep it has been warm, tho not really down here in Melbourne Town right now. I have, however put my first four tomato seedlings in.
Grumphy, I’ve been watching to see whether anyone stepped out of line in confusing weather observations with climate. The only possible exception is Paul Burns @ 4. I didn’t think anyone would confuse his opinion of the elders with an authoritative statement on climate change.
But he may well be right, it’s just too early to say on a scientific basis.
At 12 Roger Jones said:
In Brisbane we definitely stepped down in rainfall in 2000 after good rain in 1998 and 1999. But I read somewhere recently that Qld’s millenium drought is only just longer/worse than the federation drought. So I’ll wait until the climate scientists declare it AGW. Meanwhile in the post about the recent report by Will Steffen Climate change 2009: faster change & more serious risks I summarised what he said this way:
In the case of El Nino, I think he meant in relation to AGW. I didn’t try to summarise what he said about the Indian Ocean Dipole.
Steve S @ 43, that’s interesting about the intensification of the subtropical ridge. I’d noticed a lot of large highs over the southern part of the continent and the lows also intensifying and being pushed further south. I’d associated it also with the tightening of circulation around Antarctica, which I believe is due to the ozone hole, which of course is far from fixed.
It could be related to the expansion of the tropics, which I understand involves stronger uplift in the centre of the tropical band with dry air then coming down at the extended edge of the band. Hard to explain without a diagram, but try this one or put “hadley circulation” into google image -eg this or this.
That’s definitely associated with AGW.
wozza2 @ 35, I think some people are snarky because that’s what they do. I mentioned the hot weather at the beginning of the post as a kind of free association in my mind and Paul N’s “just sayin’” should have been a clue. People like to talk about the weather.
I mentioned the study last year that predicted a pause in warming because it’s there, but I’m inclined to think the criticism of it was valid.
I was a little surprised that in the most recent study the change in the solar cycle was given such prominence, but my job here is to report what scientists are saying. It doesn’t mean the whole AGW thing is overturned, so settle down!
Elise @ 37, 2m isn’t the upper limit as such, merely the upper limit by 2100 according to one study that to me made a fair bit of sense.
The USGS article is fine, as far as it goes, except that they give 8m for West Antarctica instead of the usual 5. Glaciologists used to think that it would take about 6000 years for ice sheets like Greenland to melt. Hansen et al are saying “considerably less” but I don’t recall them being too specific.
As to the paleoclimate record, have a look at the third image in this post and the first image in this one. Note especially the dot for Pliocene 3 million years ago when the sea level was 25 metres up on now, plus or minus 10.
I’m no longer inclined to be as formulaic as I was in the five statements just after the second figure on that post, but each has a basis in what has happened. We’ve had a lot of icy climate in the last 3 million years and now east Antarctica in 4k high, which becomes a factor in itself. The elevation makes it extra cold and it’s very dry, only a few mm each year. So now that it’s there it’s probably got some extra stability. It will probably melt a bit around the edges, but there’s likely to be extra precipitation further inland.
Another factor going a long way back is the shape of the ocean basins. So at some stage the sea level was considerably more than 80m higher than now.
I haven’t studied the sea levels during the Holocene, but what Grumphy said @ 38 makes sense. The temperature was a bit higher back then. But the bottom line is that if the temp goes up by a degree or two and stays there for centuries you can expect quite alarming sea level changes to follow. We just don’t know how quickly.
It’s not just a matter of steady incremental warming as I understand it, but possibly some quite wild developments as feedback loops kick in and synergies between different weather/climate elements emerge – have I got that approximately right? Here in Melbourne, I can’t help but feel that gale force winds are on the rise. Is this so, or is it just my observation?
To the commenter above with the tomato seedlings – I’m very glad I haven’t done that, with the wild tornadoes yesterday and more predicted for today! We did however get a bit of a rain deluge in our area, for which I’m hugely grateful.
Helen – ‘To the commenter above with the tomato seedlings – I’m very glad I haven’t done that, with the wild tornadoes yesterday and more predicted for today’
The wind is a bother,and it is a bit of a gambit, but our vegi patch is well sheltered. I blame my inner Canberran, who doesn’t feel too cold.
Re the solar cycle and warming; the way it was explained to me, back in the bright but hazy early ninties, was that during the solar maximum the sun delivers more energy to the earth. during the solar minima there is less energy delivered to the earth. ( wellduh). the greenhouse gases help trap that energy in the earth’s atmosphere. all other factors being neutral there will be a considerable lag time, after an injection of greenhouse gases into the atmosphere, before the maximum temperature range is reached. the temp was expected to rise in steps associated with the solar cycle, highest temps around the solar maxima, lower around the minima. The analogy that was offered was late summer. the temps around the summer solstice are rarely the highest of the season, they often occur in the following months. i hope that that made sense.
That makes excellent sense, as throughout the nineties I discovered that it was much hotter in February than January, now march is giving February a run for its money and April can get really hot sometimes. All this is my impression though
Helen @ 50, to further the point (it is my understanding that) they don’t know what all these loops and counterloops are…let alone being able to model them!
Looking at the sea level rise graph I was reminded of graphs for stability in aerodynamic design. The graphs read another way therefore, indicated to me periods of disturbance, the wiggly lines showing positive dynamic stability (tendency to return to a stable state after the disturbance or displacement) but the shifts upwards over time are accompanied by a change to a new state of equilibrium followed by further wobbles (more displacement forces). Since about 1998 the lines diverge from the last or previous equilibrium and appear linear with increasing amplitude, they now appear remarkably like the graphs for dynamic instability, that is to say the divergence is now increasing and may not return to a new equilibrium. Translated – what ever was controlling or preventing instability is no longer applicable, I think this may be then evidence of the so called hypothetical ‘tipping point’. In other words a state of being out of control. When aircraft do this they crash. Most frightening graphs of the state of our planet I have ever seen.