An observed increase in “severe” hurricanes correlates with recent warming over the period, but also with the apparent multi-decade cycle of hurricane activity in places like the North Atlantic. Your own source says the following:

…attribution of the 30-year trends to global warming would require a longer global data record and, especially, a deeper understanding of the role of hurricanes in the general circulation of the atmosphere and ocean, even in the present climate state.

Given that we know:

1) there have been periods in relatively recent history (e.g. 60 and 110 years ago) that produced as many (and possibly more) severe storms in the North Atlantic, suggesting cyclicality;

and

2) there isn’t a strong causal link between sea surface temperature and hurricane severity

there is no reason to believe that the activity we’re seeing now represents anything out of the ordinary, or confirmation of a link to global warming.

I had a look at Stern and the IPCC and couldn’t find a reference to hurricanes, so it didn’t figure large in their thinking. There is a lot about more droughts and more floods and disappearing meltwater affecting the food supply of over a billion people.

The reason why we’re discussing hurricanes at length, Brian, is that YOU chose to use them as a cautionary example of AGW in action. What has since been demonstrated is that there is no reliable scientific connection between AGW and hurricanes now or in the future. You were scare-mongering.

Moreover, what has been proved here, as I knew it would, is that you are using the science to confirm your bias, not question it.

That seems to accord pretty well with Knutson and Tuleya’s paper of 2004 from Mark Lynas’ account of it (abstract here). Of course they were playing around with models.

The paper you link to criticises them for using a 1% CO2 annual increase which is double what we have at present. But what they ended up with was a doubling of CO2. That could easily happen by 2080 because the annual rate is increasing.

They then look at storms from 1944 to 2002, but only in the North Atlantic basin. They again regard categories 3-5 on the Saffir-Simpson scale, but also look at the 5 strongest storms per annum. Since we’ve only had about 30% increase in CO2 levels during that time and given the other limitations of the study, I’m not sure it is of any great significance.

Turning to the GIT study the slab of text you quoted related to the number of storms and the days duration, not to the severity. On hurricane intensity, they say this:

Examination of hurricane intensity (Fig. 4) shows a substantial change in the intensity distribution of hurricanes globally. The number of category 1 hurricanes has remained approximately constant (Fig. 4A) but has decreased monotonically as a percentage of the total number of hurricanes throughout the 35-year period (Fig. 4B). The trend of the sum of hurricane categories 2 and 3 is small also both in number and percentage. In contrast, hurricanes in the strongest categories (4 + 5) have almost doubled in number (50 per pentad in the 1970s to near 90 per pentad during the past decade) and in proportion (from around 20% to around 35% during the same period). These changes occur in all of the ocean basins. (Emphasis added)

The GIT people limited their study to 1970 so they could remain within the satellite surveillance period, so it should be reasonably complete. Please note that they missed the exceptional 2005 season.

I had a look at Stern and the IPCC and couldn’t find a reference to hurricanes, so it didn’t figure large in their thinking. There is a lot about more droughts and more floods and disappearing meltwater affecting the food supply of over a billion people.

But severe storms even if not more intense than the past (and the GIT mob found no increase in the maximum wind speed) combined with sea level rise and storm surges could be a worry here and there.

As I said, the heavy-lifting here is in policy formulation and action. Perhaps your notion of ‘Science’ encompasses this reality, and thus lawyers, econometricians, financiers, and so on are all “Scientists.” Alternatively, you might think policy action should be the sole preserves of astrophysicists, geophysicists, and so on?

I believe I’ve addressed your issues.

That’s as may be, but you’re still coming to the wrong conclusions.

Your source on the GIT report also shows that:

In summary, careful analysis of global hurricane data shows that, against a background of increasing SST, no global trend has yet emerged [my emphasis] in the number of tropical storms and hurricanes. Only one region, the North Atlantic, shows a statistically significant increase, which commenced in 1995. However, a simple attribution of the increase in numbers of storms to a warming SST environment is not supported, because of the lack of a comparable correlation in other ocean basins where SST is also increasing. The observation that increases in North Atlantic hurricane characteristics have occurred simultaneously with a statistically significant positive trend in SST has led to the speculation that the changes in both fields are the result of global warming.

Note the word “speculation” in that last sentence, and that the study does not capture the long-run data of the NHC, which shows that the 2004-2005 surge in hurricane landfalls matches previous - apparently multi-decade cyclical - peaks in the 1950s and 1890s. It’s also worth pointing out, as Landsea does, that much of the observed recent (i.e. last few decades) increase in observed hurricane frequency in the North Atlantic may simply be due to better monitoring (i.e. via the use of aircraft and, more recently, satellites).

As I noted earlier, there is simply no evidence that Global Warming has caused an observed and material increase in hurricane frequency and/or severity.

As to whether increasing sea surface temperature (SST, presumably due to global warming) WILL cause more hurricanes, I refer you to your own source on Landsea. Better yet is his 2005 paper with Michaels and Knappenberger, which observes that SST is only weakly correlated with hurricane frequency and severity:

Instead, the combination of observed greenhouse gas forcing trends, weak correlation between SSTs and tropical cyclone intensities, high interannual and interdecadal variation in tropical cyclone characteristics, and the use of a mesoscale model that shows difficulties in predicting current-day hurricane intensity changes suggests that the influence of atmospheric composition changes on future hurricane intensities will be undetectable in the foreseeable future and, in fact, may never be manifest.

This is not to say that I believe Global Warming definitely WON’T cause more mayhem etc. but there’s just not enough scientific evidence to suggest it’s going to cause significantly more frequent and/or severe hurricanes.

WBB, I believe I’ve addressed your issues.

Or are you merely saying that, statistically, we haven’t seen more hurricanes and cyclones up to this point?

Reading your very readable link I see that regarding storms:

Activity during 2005 was far above the previous records for the most number of tropical storms and hurricanes, but 1950 is still the record-holder for the maximum number of major hurricanes.

Fyodor, there are outliers, sure. There is also global warming.

I don’t regard you as a “delusional wingnut” etc. I’d regard you as an AGW sceptic. Sceptics perform a useful role if, like you, they are rational.

I’d also readily concede that you might know more about the insurance industry than I do.

Let’s just deal with hurricanes tonight, or tropical cyclones to distinguish them from all the other cyclones.

I didn’t say there were more of them. My memory was that there may even be fewer as the ocean warms, that they might turn up in places where they haven’t been seen before (that happened fairly dramatically in 2004 and 2005, but I’ll spare you the anecdotes) and that there may be more severe tropical cyclones.

It turns out that a bunch of scientists at the Georgia Institute of Technology published an article in Science which found:

We conclude that global data indicate a 30-year trend toward more frequent and intense hurricanes, corroborated by the results of the recent regional assessment (29). This trend is not inconsistent with recent climate model simulations that a doubling of CO2 may increase the frequency of the most intense cyclones (18, 30), although attribution of the 30-year trends to global warming would require a longer global data record and, especially, a deeper understanding of the role of hurricanes in the general circulation of the atmosphere and ocean, even in the present climate state.

The difference is that they looked world wide, they looked at 1970-2004 and they looked for categories 4 and 5 whereas the study you cite focuses on the US, a longer time period and categories 3-5.

I know this whole area is sensitive because Chris Landsea spat the dummy with the IPCC process (understandably).

It seems to be a no-no in decent climatological circles to attribute any particular cyclone to global warming, but the interest is in the pattern.

Here it seems to me logical that if there is more energy in the ocean and lower atmosphere from global warming there will likely be more cyclones. But this may be impacted by other changes, eg. what happens to El Nino (uncertain) and what happens to the wind-sheer effect of upper-air winds.

As the Georgian scientists say, it’s too early to say definitively that the pattern they observe is related to global warming. The whole AGW edifice doesn’t stand or fall on that. It’s just another area where a pattern that suggests that GW is causing CC seems to be emerging.

Obviously. But when the trends are so strong and it’s hard to see what’s going to change them it seems prudent to take steps to mitigate what’s happening if it’s not benign.

OK, so trend isn’t prediction, except when it’s really “strong”? Scientifically useless.

I’ve heard climatologists say repeatedly that while we are always going to have extreme events and break records, it is the number of exceptional events in recent times that is exceptional. That happens to fit what climatologists expect from global warming.

Oh really? Where do they predict these supposedly exceptional events? The reality is this: Australia has bushfires, the Gulf of Mexico gets hurricanes, Tsunamis are typically caused by earthquakes, yadda yadda und so weiter.

You say you understand confirmation bias, but when pressed you wheel out anecdote after anecdote confirming your bias.

So what’s the big deal about taking a bit of precautionary action, since it won’t cost much, might even make us more efficient and boost the precious economy?

“Trust me, this won’t hurt a bit…” Oh, that’s alright then.

Here’s an idea: howsabout you tell me what’s going to happen, and what it’s going to cost to prevent it. Then we can have a sensible discussion about policy.

On the insurance industry, the increased pattern of unusual events was smacking them about a few years ago. When I heard that if QBE suffered another hurricane Mitch then they’d be in trouble, I sold out. Turns out they didn’t get another hurricane, have factored the increased risk into their premiums and have done well. The action in the insurance industry affects most industries, so they’ve been the bellwether in business taking AGW seriously.

OK. Stop right there. Let’s call this Exhibit “Q” of the Global Warming Hysteria Confirmation Bias in Action (GWHCBA).

QBE, and other insurers that insure property around the Gulf of Mexico and Eastern USA, EXPECT hurricanes. They expect to pay out on hurricanes. Why? Because hurricanes are a regular, seasonal occurrence in the North Atlantic.

There is NO EVIDENCE that hurricanes have increased in frequency OR severity due to global warming.

In fact there is nothing particularly unusual about recent hurricane activity.

If you doubt me - and I’m guessing you do, because I’m the delusional wingnut deprived of all that scientific factual goodness you value so highly - read the historical report (PDF) prepared by the USA’s National Hurricane Centre. No, it’s not an astroturf operation funded by evil petrojuggernauts intent on destroying the Earth. It’s the US government agency tasked with tracking hurricanes, and they do a good job of it.

The particular piece of factual goodness you should refer to is Table 6 on page 13, which shows that the yearly frequency and severity of hurricanes making landfall on the USA is not extreme, and is actually LESS than it was in the highly active 1940’s and 1890’s periods.

So why do the insurers make so much noise about hurricanes? Because of something called risk concentration.

It IS correct that the last few years have been hugely expensive for insurers of these hurricane-prone areas. Why? Because, in their unwisdom, Americans have decided to build lots of expensive property in places like Florida, Louisiana and Texas. WEATHER is not the key variable that has changed in the last few decades; the quantity of insured property at risk is what has changed.

When the insurers modelled [that word again - seeing a pattern yet?] their risk exposures they consequently under-estimated the potential economic and insured losses from a major hurricane strike in the GoM. Insurers increased premium rates for windstorm risk in vulnerable areas of the USA after Hurricane Katrina, but insurers always charge more after a major catastrophe, because they can. But then good ol’ market forces kick in so that more capital is supplied to the market and rates come down again.

But don’t take my word for it [I don’t know what I’m talking about, remember?], take the word of the world’s leading reinsurance broker, Guy Carpenter, a division of Marsh, Inc. Allow me to quote from their report on recent pricing of catastrophe risk (page 2):

As the property section of this report indicates, rates at January 1, 2007 renewals for U.S. property catastrophe were below the levels of July 1, 2006 renewals. Given that nearly all other lines are experiencing rate decreases or renewing at expiry, we can now conclude that the U.S. reinsurance market overall has entered the soft phase of the cycle. If history is a guide, we can expect soft market conditions to persist for many years. This will be the “normal� state of the market.

That’s right: prices rose…and now they’re falling - the underwriting market cycle at work. BFD.

Conclusions for Global Warming? Big donut.

What has the insurance industry done about Global Warming? SFA.

How have they jumped on the bandwagon? By attempting to convince people that global warming means they should pay more for insurance. Well, they would say that, wouldn’t they?

So, please, next time you feel tempted to attribute all these “exceptional” one-in-a-gorillion years hurricanes to Global Warming, just remember this lesson and apply a little skepticism before you shoot your keyboard off with some meaningless anecdote.

Mark Lynas in his book Six Degrees goes into the Greenland thing in some detail. The important new information is that a European modelling team worked out that the “critical melt threshold” for Greenland was 2.7C of warming. This was likely to occur when the global temperature rises by 1.2C (which is inevitable) because Greenland warms at 2.2 times the global rate.

But such modelling “treat the ice sheet like it’s just an ice cube sitting up there melting”, it doesn’t take into account the dynamics if ice sheet degradation.

He then gives a series of worrying observations, including Kangerdlugssuaq which both doubled in speed and simultaneously retreated 4 kilometres between April 2004 and April 2005. He gives similar information about others including Jacobshavn Isbrae, a huge glacier that contributed 4% of 20C sea level rise.

Then on The Science Show there was an interview with the splendid David Karoly, Federation Fellow School of Earth Science at the University of Melbourne, who goes into considerable detail about what’s going on with sun spots and stuff. Sun spots go on an 11 year cycle which doesn’t fit what’s happening. Longer cycle influences are far too weak to drive what’s happening now.

This was followed by Ian Enting, Professorial Research Fellow Centre for Mathematics and Statistics of Complex Systems at the University of Melbourne, who is developing the next generation of climate model, in particular the role of carbon in the land surface, plus looking at what it would actually take to stabilise concentrations of atmospheric carbon dioxide.

Transcripts of both should be up in a few days.

Sorry, I did misrepresent your absurd belief a little. My bad - I should have read that sentence over before I posted my comment.

Your absurd belief is actually that the political campaigning to get action on global warming is a conspiracy against the workers and that the scientific evidence should be rejected because it comes from bourgeois lackeys and stooges of the oppressor class:

A dead give away about the “scientific evidence� is that instead of advocating such measures (whether R&D on fuel replacement, or dealing with the consequences of continuing to use carbon based fuel or mitigation) they [ advocate measures that are designed to slow economic growth and make people feel guilty about wanting a higher material standard of living. This is characteristic of people who are opposed to economic development as such, rather than having a belief that there is some concrete problem that really needs to be dealt with.

‘A complete melt of the (Greenland) ice sheet would cause a global sea level rise of about 7m; but the current picture indicates that while some regions are thinning, others are apparently getting thicker.’

Why didn’t you also quote this one:

In 1996, Greenland was losing about 100 cubic km per year in mass from its ice sheet; by 2005, this had increased to about 220 cubic km.

It was immediately above the one you quoted.

Did you open this image nearby?

It shows clearly more melting in 2002 than in 1996. We’ve known for nearly a year now that the melting speeded up further since 2004.

This article by Richard Black gives an orverview of what’s happening in the Arctic, in Antarctica, in the glaciers elsewhere and in the permafrost. The Antarctic is currently fairly stable apart from the peninsula, as you suggest. But again I suggest you open the picture and look at what’s happening in West Antarctica.

patrickm, if the ice shelves melt down there it will be because the sea is warmer, This means that the warmer sea will be in contact with the ice all around the edge of Antarctica. The melting there and of the large ice shelves would precipitate an increased glacier flow off the eastern part and seepage under the ice in the western part, because the rock is under water.

BTW, I think there is a mistake in the BBC article you linked to:

Studies suggest that even during the last interglacial (116,000-130,000 years ago), when temperatures were thought to be 5C warmer than today, the ice persevered, keeping the delicate samples entombed and free from contamination and decay.

Re the bit I’ve higlighted, I think the temperatures were only 1-2C higher. The sea level was 5-6m higher.

On Gore, Eric Steig at RealClimate said this:

How well does the film handle the science? Admirably, I thought. It is remarkably up to date, with reference to some of the very latest research.

On sea level rise, this article by Hansen (pdf) goes into Rahmstorf’s calculation of a one metre rise this century if the process turns out to be linear, and Hansen’s estimate of 5m if it turns out to be non-linear (more likely).

For homework I wonder whether you wouldn’t mind reading this article by Hansen and about 45 of his fellow scientists (pdf) and tell me where they went wrong.

GT

…thanks to your absurd belief that global warming is a conspiracy against the workers.

I have no such belief and you either know this or ought to. Your technique of not addressing what was said and pretending that something else was, and then looking for motives (this person’s views are different than mine what are his motives) is more than just annoying. It rules out any ability to conduct a discussion that requires addressing the questions openly and honestly.

I am saying openly that on the evidence we have before us, humans are remarkably adaptable and capable of solving problems that emerge as we industrialize. On the evidence that there is a thickening on average of the Antarctica, and no credible evidence of an imminent (next several hundred years) melt of Greenland, massive ice melting causing sea level rise is a non starter for an immediate resort to the measures that are regularly promoted on LP.

The proposals for a carbon tax of one sort or another are nothing if they are not intended to lower the use of carbon, either in the amount of flying that people engage in, or driving, or use of the cheapest electricity in Australia.

This is not a conspiracy it is a series of proposals that are currently under discussion and GT is fully aware of it. GT also knows that what I have said about Peter Garret being more likely to take proposals to reduce the use of carbon more seriously than say John Howard is considered quite matter of fact here at LP. People on this site have often said that Howard does not take the issue of AGW seriously enough to take the measures required to lower the use of carbon. I tend to agree with them and predict that when battlers become more familiar with that proposition they will vote for the political party that will do least (but fund more science).

Brian;

when some of the most distinguished climatologists on the planet are saying they think 1-5m by 2100 is the likely range. The biggest uncertainty is in the timing, not in the quantum of sea level rise.

then I say show me where the quantity is going to come from because those potential figures require ice melt from the two areas that are not melting in the way that the scare theory predicted.

Peterc

A lot of skeptics have swung into gear of the back of GGWS, including patrickm. For the most part, I think their shallow attempts to deny and distract are not working too well. But we can expect to see more of this over the coming election campaign as they seek to keep major party policies on climate change ineffective and irrelevant.

Yes, you can expect to be subjected to criticism, and you can pretend that you are not religious in your attitudes and are ever so scientific, while not engaging with anything actually said by the evil critics - but that won’t save you from the vote when the battlers face up to the issue.

Brian; ice shelf melting has nothing to do with sea levels rising because the ice is already in the water! I believe that the evidence is that currently more ice is accumulating world wide than is melting. Dishonest efforts like Al Gore got up to with his smash hit film ought to be subjected to the same sort of effort (and Stern etc) that the ABC put into this effort. Tony Jones was exposed for bias.

Just putting on a debate was very useful and we ought to get many more from the ABC even though Flannery etc say the debate is over. It has really just begun. We saw that the ABC was utterly incompetent in the manner that they conducted this effort. Hardly a question even made any sense, the audience was a complete shocker, yet there are many worthy questions so who was responsible for putting nonsense to air when we could have easily had good questions and debate?

Yesterday I had the misfortune to hear again the Counterpoint interview with Martin Durkin. I misspoke further up the thread (or somewhere). I said that the working title for the film was Global warming, my arse! I should have said the original title was Apocalypse, my arse!

I did hear a report of what you say on the radio. You have to remember the Greenland under the ice is shaped like a saucer. The ice doesn’t come in contact with the sea all that much.

The maps of warming show that the northern hemisphere, especially in the higher latitudes, is warming most. When the warmth is transported to southern climes, which takes time, you are likely to see more warming around Antarctica.

The Antarctic, OTOH has large ice shelves, is majorly in contact with the sea, and West Antarctica is mostly below sea level. So the notion that all the sea-level rise has to come from Greenland is bullshit.

The paleo record shows that during the last interglacial with temperatures 1-2C above now we had the sea 5-6m higher.

Three million years ago with the temp 2-3C above now the sea was 25m (plus or minus 10) higher.

It also takes time for the heat to transport to the bottom of the ocean floor. I recall 100 years in one report. This will produce thermal expansion, but frankly I don’t know how big a factor that is.

Finally I did hear on the BBC, as I stated in the last comment, that sea-level rise is moving faster than predictions. So there is no warrant for you to say the “sea rise over the next century is just a non issue”, especially when some of the most distinguished climatologists on the planet are saying they think 1-5m by 2100 is the likely range. The biggest uncertainty is in the timing, not in the quantum of sea level rise.

When you are not hiding behind a pseudonym to stalk students who have the temerity to use their own names and share honestly with other members of a cyber-community, are you a university teacher? If so, no wonder you hide behind a pseudonym.

I have heard there are many bitter academics who ‘get their revenge’ on students when grading papers or through mining administrative edicts.

While I am reasonably astute at detecting what type of person carries on in this way, sadly most 20 year olds would not be able to pick such pillocks in advance.

He is also moderating blog comments to keep the focus squarely on biffo and bullshit.

Here is my comment, with the part he moderated out in bold:

So Jack, according to you there is no consensus or agreement about climate change happening. So we do what? Nothing? Maybe just keep out pumping out facile opinions?

It is common PR tactics to seek to confuse people. You make a few assertions, provide some dodgy links, dish out a bit of abuse.

Why do have the “last word” on critical posts? Like to put a bit more fat on the fire, or are you just a bit too defensive? Got something to hide? I will know if you moderate this post.

The debate has actually moved on past skeptic crackpots and PR folk seeking to distract and befuddle, even though you seek to dally in that space.

The big issue is that neither Howard or Rudd is actually committing to do anything about reducing emissions until some unspecified time before 2050. Actually, Howard hasn’t committed to do anything at all yet. Even though we are having the hottest and driest years on record. Shame, shame, shame.

I didn’t realise The Age had someone like the Bolter on their payroll. Then The Age queries in their editorial today “But has politics won at the price of science?”

A lot of skeptics have swung into gear of the back of GGWS, including patrickm. For the most part, I think their shallow attempts to deny and distract are not working too well. But we can expect to see more of this over the coming election campaign as they seek to keep major party policies on climate change ineffective and irrelevant.

Meanwhile, Arnold Schwarzenegger and Europe lead the way on climate change. Germany has just announced a 40% MRET target, while Australia languishes at 2% (Howard) with Labor refusing to specify what theirs will be . . .

First up, what’s the source of that quotation you’re arguing from? You wouldn’t be holding that back because you’re worried that someone might shoot you down by looking it over and finding that your evidence doesn’t support your argument, would you?

One lesson you could have absorbed from the GGWS debate you evidently missed - Durkin tried to win a political argument by discrediting the scientific evidence for global warming. To do that, he ignored a considerable body of evidence that didn’t support his own argument. That’s why it was so easy for Tony Jones to fillet him in the post-doco interview (the ABC should really put a transcript of that on-line).

You’re trying to do exactly the same thing, thanks to your absurd belief that global warming is a conspiracy against the workers. It’s no more a conspiracy against the workers than the floods that sometimes wreck the homes of workers who bought houses built on flood plains (a real problem in some areas of Melbourne, thanks to some dodgy town planning approvals in the past).

In the example I’ve just given who really advances the interests of the working class - the “pseudo-leftist” who campaigns for adequate flood control measures? Or the ideologically blinkered “true-leftist” who insists that all this talk of possible future floods is an obvious ploy to push property values down, reducing the workers’ re-mortgageable equity in their homes?

So, now those were rhetorical questions were they?

That in no way changes the fact that you started with a complete misunderstanding, or misrepresentation of the business of science - as Hilker and I both reminded you, science is in the business of making predictions and scientific theories are tested not merely by how well they describe known phenomena but by whether what they predict matches what we find when we go out to test them.

An example - according to both the old paperback popularisations of Einstein’s Theory of Relativity, Einstein won out over Newton because his theory made two very precise predictions - one concerning “gravitational lensing” , the other concerning the perihelion of the planet Mercury - that were tested experimentally and the results were: Einstein two correct predictions, Newton zero. After that it was all over except for the academic politics.

If you begin by getting something so fundamental wrong, don’t expect me to take anything that follows from there seriously. Especially if, as is your habit, you are unable to refrain from spicing your comments with remarks that make it quite clear that you consider everyone who has the effrontery to disagree with you a fool.

Despite the fact that you evidently consider so many people who post and comment on this site fools, you keep returning here to argue with them. There’s a saying about people who argue with fools, I’m sure it’s familiar to you.

You sir, have shown yourself, time and again to be a fool. Why do I persist in the foolish habit of arguing with you? For my own amusement and the amusement of readers of this blog. And because I can’t quite shake the foolish hope that if you’re exposed as a fool often enough, you might one day show the good sense to shut up on subjects of which you are deeply ignorant.