When the rain comes…

by Gareth on June 22, 2010

The extreme weather flavour of the moment is without doubt heavy rain and flooding. As I write, severe flooding has caused 132 deaths in southern China and 19 in Burma. The Var region in southern France is recovering from spectacular flash flooding that killed 25 people (watch the BBC video), Tennessee’s recovering from a 1000 year flood in May, and NZ hasn’t escaped. The Metservice blog reports that the flooding in Whakatane a few weeks ago was caused by rainfall of 89.8mm in one hour (with more heavy rain either side of that hour). As the blog notes, that’s tropical rain happening well outside the tropics. But what struck me at the time was a comment from a Whakatane resident included in the TV3 News coverage of that flooding. I can’t remember his precise words, but it was something along the lines of “should be a wake-up call for anyone who doesn’t think global warming’s an issue, because this is what global warming delivers…” Perceptive, I thought, because one of the more robust predictions of climate science is sometimes described as an intensification of the hydrological cycle.

It works like this. Increasing CO2 in the atmosphere warms the planet. As the oceans warm up, more water vapour enters the atmosphere, and because it is itself a heat-trapping gas this adds to the warming. This positive feedback is important because it increases the amount of warming triggered by the CO2, but it’s also important because of impacts of the increase in water vapour itself. The increase has been measured: there’s about 4% more water vapour in the atmosphere now than there was 30 years ago, and I suspect that we’re now seeing the effects of that on our day to day weather.

Water vapour is sometimes described by meteorologists as the “fuel” that drives storms. As water evaporates from a warm ocean, it cools the surface and transfers energy into the atmosphere. As the water vapour condenses into clouds and rain, that energy is released, intensifying the storm. More water vapour, stronger storms, heavier rainfall.

4% extra water vapour doesn’t sound like a lot, does it? But it’s enough to change the probabilities of heavy rainfall events in two ways. Firstly, the frequency of heavy rainfall events will increase, and secondly the amount of rain that falls in the heaviest events will increase. Take a look at this graph (from NASA’s Earth Observatory feature on the costs of climate change):

extreme_events_mid.gif

The graph considers temperature extremes, but the same principle applies to rainfall (except that the probability distribution is pegged at zero — no rain). The top curve shows what happens if the climate warms but the variance — the size of the swings between warm and cold — remain the same. The middle curve shows a stationary climate (ie, not warming or cooling) but with a variance increase — more dramatic swings between hot and cold, but no new records. The effect is to squash the curve and create more warm and cold events. Combine the two, and you get increases in both the hot weather and in record heat. This is already being seen with heatwaves in Australia, for instance, and I suspect we’re now seeing the same effect happening with rainfall.

Joe Romm at Climate Progress has been diligently pursuing the issue of weather extremes as a symptom of climate change, and last week interviewed NZ scientist Kevin Trenberth, head of the Climate Analysis Section at the National Center for Atmospheric Research in Boulder, Colorado, on the subject. It’s worth reading the full interview, and following the references, but here’s Trenberth making an important point. Romm asks about the best way to describe the increasing extremes:

I find it systematically tends to get underplayed and it often gets underplayed by my fellow scientists. Because one of the opening statements, which I’m sure you’ve probably heard is “Well you can’t attribute a single event to climate change.” But there is a systematic influence on all of these weather events nowadays because of the fact that there is this extra water vapour lurking around in the atmosphere than there used to be say 30 years ago. It’s about a 4% extra amount, it invigorates the storms, it provides plenty of moisture for these storms and it’s unfortunate that the public is not associating these with the fact that this is one manifestation of climate change. And the prospects are that these kinds of things will only get bigger and worse in the future.

Earlier in Romm’s interview Trenberth had drawn attention to research that demonstrated that in the US, “the really heavy rainfall events — the top 1% and the top 0.3% — had gone up at even more alarming levels something like 27% as I recall over the last 30 or 40 years [actually 1967 to 2006].” Ring any bells? Jeff Masters comments and amplifies the point here. Then try a Google News search for the term “flood“, and see what pops up.

From my personal perspective, sitting in a farmhouse in North Canterbury on the east coast of the South Island of New Zealand, deep down in the South Pacific ocean, I think we’re seeing this effect quite clearly. I haven’t crunched the numbers for New Zealand, but I think they might show the same thing as the research Trenberth quotes. I’ve pondered the subject before, when considering the evidence of my rain gauge in 2008 and the climatic swings of 2009, but I can’t help but feel that as we head into the second half of a year that might set another global temperature record, we’re already seeing the concomitant impacts of increased water vapour in the atmosphere in the dramatic flood events happening around the world.

The lesson: climate change is not an abstract thing, a problem reserved for the future. It’s not only a slow but steady increase in long term averages, it’s also a change in the probability of extreme events, which are themselves becoming more extreme. The impact of climate change will be delivered by changes in the weather that we experience — and those changes are already happening. Worse, when the weather’s bad, it can and will be very bad indeed.

[Update 23/6: The Guardian reports on a new paper which suggests intensification of the hydrological cycle will persist, due to the thermal inertia of the global ocean, for a considerable period after CO2 levels have stabilised and been reduced. And Nature News discusses the terrifying power of flash flooding...]

[Fabs]

{ 53 comments… read them below or add one }

Steve Wrathall June 23, 2010 at 9:42 am

Here we go again. Another attempt to retrospectively corrrall any notable weather event as evidence for imminent climate doom. If France Tennesee, and Whakatane were experiencing boring weather would that be evidence against the impending atmospheric apocalypse?
“can’t account for the lack of warming at the moment and it is a travesty that we can’t,” – Trenberth

Gareth June 23, 2010 at 9:55 am

The whole point of the post, Steve, is that the evidence is in the extremes, not the boring stuff. And as you well know, your Trenberth quote doesn’t mean what you think it means… but then you knew that, didn’t you…

SCM June 23, 2010 at 9:59 am
C3P0 June 23, 2010 at 10:03 am

Yeah, you will not convince me this is a scientific analysis of recent weather

Gareth June 23, 2010 at 10:04 am

Yeah, and the Arkansas flash flood, the Oklahoma floods (in the Jeff Masters link above), and, and…

Gareth June 23, 2010 at 10:07 am

C3: My post is not, nor do I claim it to be, a “scientific analysis”. I wanted to point out how extremes of rainfall are consistent with what we would expect to see as the planet warms. And we should acknowledge that fact, not try to dismiss it out of hand, a la Wrathall.

RW June 23, 2010 at 10:11 am

Put a sock in it, Wrathall – if your first comment above is indicative of your intelligence.

C3P0 June 23, 2010 at 10:45 am

Gareth, comment 6. I just don’t think you help anyone by compiling such a list of anecdotal evidence. All that it achieves is the provocation of a counter list next time a bunch of cold event happen to occur at the same time around the world (like last NH winter).

And also there is only a loose and unproven link between warming and heavy rain fall. I of course understand the simple theory you present but the reality is far more complex, and I believe actual research shows an increase in heavy rainfall during cold periods in history.

Gareth June 23, 2010 at 10:55 am

C#: We’ll have to disagree (not for the first time). I’ll be writing about “cold events” in the near future, but you probably won’t like what I have to say about them, either… ;-)

As for the link between warming and heavy rainfall, I suggest you read a few of the papers Jeff Masters refers to in this post. It’s not “loose and unproven”: it’s expected and observed, and documented in the literature.

Bryan Walker June 23, 2010 at 11:01 am

#8 C3PO it’s not a matter of compiling anecdotes. The prediction is for more extreme weather events, including heavier rainfalls. All predictions are unproven until they occur. It is literally impossible to attribute any one extreme event to climate change, but the balance seems to me to be indicating that we are very probably seeing the beginnings of the changes predicted and should be accordingly alarmed.

bill June 23, 2010 at 11:03 am

C3PO @ #8

and I believe actual research shows an increase in heavy rainfall during cold periods in history.

Prove it!

I’ve been pondering the same points with (how many?) spectacular flood events occurring worldwide in a short period (I got caught in one of them only a month or so so ago!)

Those who don’t possess a brand of ‘scepticism’â„¢ that applies solely to one side of the argument – and is also, ironically, quite happy to become an ‘extreme event’ in itself – might acknowledge that the circumstantial evidence for the well-known argument Gareth is making is pretty damn compelling…

Whereas handwaving references to ‘actual research’ only indicates a lack of it!

Girma June 23, 2010 at 12:21 pm

Unverifiability is a cosy position to hold in a debate. Draughts, floods, heat waves, and increased snow are all caused by man made global warming. Fortunately, it is not a scientific position.

Steve Wrathall June 23, 2010 at 12:29 pm

RW, no need for me to put a sock in anything, as you warmists, with your normal love of free speech have hidden my comment. You guys really like to “hide” things eh?

Must be wonderful having beliefs, where every event, normal or abnormal, confirms them, Sort of like religion without the annoying pedophile and flying into buildings stuff.

Gareth June 23, 2010 at 12:45 pm

Girma @ #12:
The change in extreme rainfall is not unverifiable. It’s there in the numbers, as USCAP analysis showed for the USA (see Jeff Masters link above). A look at the NZ numbers might be interesting — I’ll ask around.

Steve: Your comment is only a single click away from being seen. No censorship involved. It simply shows you are not contributing to a useful discussion. That said, I might take Stephen R’s advice and raise the bar (number of votes required to “hide”) a little.

Steve Wrathall June 23, 2010 at 12:51 pm

And your evidence is also “consistent with” what global weather events would be expected with normal variability. This is the null hypothesis for which the burden of evidence is on you to disprove.

And yes, you can expect a 1000-year flood somewhere in the world every year. This year it’s Tennessee (<1/1000 of global land area), next year it'll be somewhere else. The only certainty is it will be pounced on by the climate vultures as more "proof".

132 deaths in China. Sad but considerably less than the millions that died in the 1931 Chinese floods. That's what happens when people are allowed to build all this CO2-unfriendly infrastructure, which you guys would deny them.

bill June 23, 2010 at 12:57 pm

At least Steve doesn’t think we’re pedophiles!

And Girma’s on topic! A red letter day! With regard to the attribution of any specific event unverifiability, however, is a fact of life, not a ‘cosy position’. ‘Warmist’ theory holds that a hotter atmosphere holds more water AND more energy, leading to an increase in exactly the kind of events we’re now seeing a striking number of across the world, and not just in a localised band at certain latitudes in the northern hemisphere like the recent snow events (which were also also consistent with more water being available in the atmosphere and part of the warmest NH Winter period on record anyway).

In the absence of a ‘control Earth’ to compare our high-CO2 world to we just have to make risk assessments based on probability. And ‘it’s all just a remarkable coincidence’ becomes a less viable option with every year that passes and every new ‘coincindent’!

Gareth June 23, 2010 at 1:03 pm

your evidence is also “consistent with” what global weather events would be expected with normal variability. This is the null hypothesis for which the burden of evidence is on you to disprove.

Once again, you miss the whole point of the post. What we’re seeing is a shift in the probabilities, not “normal variability”.

bill June 23, 2010 at 1:11 pm

As to the number of votes to hide – I’d be tempted to suggest matching them (7 each good or bad triggers the event). I’m also dubious about ‘hiding’ comments – though I might add I’ve ended up reading almost all of them – but a measure to protect oneself from Girma’s endless reposting and restating of the same graphs and arguments seems not unreasonable.

So while a few people might react to the aptly named Wrathall’s blunt and also rather trying insertions into the debate (‘it’s a religion, I tells ya’ again, Steve? Ho hum!) it’s less likely he’ll ‘disappear’.

While Girma might learn to actually respond to counterarguments, not just restate his original position. We can but hope…

Gareth June 23, 2010 at 1:17 pm

bill @ #18

I’ve upped both sides to 5 votes for now. The problem of course is that we get far fewer “sceptics” commenting, and those that do (Wrathall, that means you) often post tripe, and so are likely to be hidden. However, it does reduce the “noise” in the thread for those who want a reasonable discussion. Use your votes wisely is the message…

Girma June 23, 2010 at 1:50 pm

Gareth.

Congratulation.

You are one of the few blogs like “DOT EARTH” that allow opposing views in their blog.

Well done. Thank you.

Steve Wrathall June 23, 2010 at 1:51 pm

“What we’re seeing is a shift in the probabilities, not “normal variability”.”

That is an extraordinary claim requiring extraordinary evidence. Sorry, anecdotes don’t cut it, especially as it is the very CO2-emitting technology you rail against that allows dramatic weather events to be broadcast worldwide, when 50 or 100 years ago, across vast swathes of the globe, they would remain unknown outside the immediate vicinity.

Gareth June 23, 2010 at 2:04 pm

That is an extraordinary claim requiring extraordinary evidence. Sorry, anecdotes don’t cut it

The evidence exists. Go read the papers, then come back and explain why they’re wrong. Good luck with that.

Girma June 23, 2010 at 2:25 pm

I wonder what I will do in my spare time once the man made global warming theory is shown to be invalid for all to see with drop in mean global temperature anomaly to a value of about zero around 2030.

Gareth June 23, 2010 at 2:31 pm

Girma: Nice try, but you’re straying off topic and back in the direction of your hobbyhorse.

RW June 23, 2010 at 2:32 pm

Girma #23, you’re talking about a null event. Just start planning your excuses and rationalisations instead.

Steve Wrathall June 23, 2010 at 2:34 pm

Name ONE (1) paper that proves that “What we’re seeing is a shift in the probabilities, not “normal variability”.”

ONE

“then come back and explain why they’re wrong.”

Nice try at switching the burden of evidence. Sorry, it is you making the extraordinary claim: that observation(s) cannot be explained unless the extra factor (increased GHG warming contributed by humans) is included.

Gareth June 23, 2010 at 2:56 pm

ONE

Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends (pdf), Groisman et al 2004.

Overview here: IPCC AR4, WG1, Chap 3, section 3.8 and FAQs 3.2 & 3.3 (you can look that up for yourself).

Girma June 23, 2010 at 3:40 pm

Unfortunately though we cannot create another planet to run a “real” experiment, so computer models based on established properties of the observable universe are the best available approach.

The experiment had already been done! The global mean temperature anomaly data has been recorded by Climate Research Unit of the University of East Anglia. The human emission of CO2 has been recorded by the Carbon Dioxide Information Analysis Centre. From the period 1910 to 1940 to the period 1970 to 2000, human emission of CO2 has increased by five-times. However, during these two periods, the rate of global warming was a nearly identical value of 0.15 deg C per decade. That is, no change in rate of global warming with increase in human emission of CO2 by five-times.

As a result, the “real” experiment already had been conducted and it shows that there is no relationship between human emission of CO2 and mean global temperature.

bill June 23, 2010 at 3:50 pm

Girma @#23

I knew it couldn’t last: I hereby declare, Girma, that I am going to press the ‘thumbs down’ button on any OT post you make. I encourage others to do the same.

The reason you’ve been blocked elsewhere may have less to do with your ‘seeker of truth’ martyrdom at the hands of tyrants fearful of the shining light you bring – as you’d no doubt choose to see it – and rather a lot to do with your obsessive restatements and constant reversions to your pet theme (currently cherry-picking WFT)!

Rob Taylor has already posted the link on the increase of Hurricane Frequency in the last century just for Girma to ignore – perhaps he can read it and practice being On Topic at the same time!

Gareth June 23, 2010 at 3:56 pm

Girma: last warning. Stay off your hobbyhorse, or I’ll have to start deleting your comments.

Steve Wrathall June 23, 2010 at 4:19 pm

Nice paper. Did you read the last paragraph?
“Of course, the most important questions would be “What causes all these changes?” and “Can we forecast that they will continue in the future?” Unfortunately, data themselves and /or their analysis can not provide answers to these questions. The most that we can do is link the observed changes to the changes in intermediate large-scale factors. Among them are general warming over the country, reduction of the meridional temperature gradient with global warming, changes in macro-circulation characteristics such as North Pacific Decadal Oscillation, annular variations in zonal circulation, El Niño/La Niña effects, or changes in the North American monsoon properties. To proceed further would be speculation.”

Nowhere can they conclude this is “not normal variability”

Try again.

In real science “Oooh look, A trend! It must be because of us!” doesn’t stand up.

RW June 23, 2010 at 4:21 pm

What’s next Wrathall – “Show me TWO….”? I’m very happy for your contributions to remain visible – the uninformed ramblings of a neoconservative polemicist. You’re the one with the belief problem.

Gareth June 23, 2010 at 4:28 pm

SteveW: The paper finds that the probabilities of extreme rainfall events have changed significantly. That’s what you wanted evidence of, that’s what the paper provides.

Given that it’s not a paper about attribution, or the world beyond the USA, it’s not surprising they make no great statements about causes. And if they did, no doubt you’d be down on them like a ton of bricks. Now go away and read the AR4 WG1 chapter and section I referenced. It’s full of carefully nuanced statements that I’m sure you can spin to mean something that fits the preconceptions you bring to everything.

bill June 23, 2010 at 4:52 pm

And while we’re on record events, please turn your attention to the charts on page two of the following –

http://www.bom.gov.au/inside/eiab/State-of-climate-2010-updated.pdf

Number of heat-event records increases, number of cool-event records decreases. Exactly consistent with the charts Gareth has posted. Now, they DO conclude that this is not normal variability!

Girma June 23, 2010 at 5:08 pm

BILL

What is wrong in pointing out that the experiment for the relationship between human CO2 emission and global mean temperature had already been done, and no wishing for another globe to do the experiment is required?

Girma June 23, 2010 at 5:21 pm

How in a sad time I live in as when the reality is we live a longer & healthier life compared to any time in all of human history, the belief of the talking heads is on things getting worse.

I hope like all other defeated ideologies, the ideology of doom will also be defeated.

Girma June 23, 2010 at 5:30 pm

Girma: last warning. Stay off your hobbyhorse, or I’ll have to start deleting your comments.

Okay.

I will just read and will not comment any more.

Terry June 23, 2010 at 6:06 pm

This past winter the snow and cold in the NH was a result predicted by the models, and now rain events are evidence of AGW. So are most any warm day and cool day and wet day and dry day and windy day, at least in the press. All events are evidence of AGW.

But the climate scientists keep saying we must not confuse weather and climate, and a clear trend over at least 30 years is needed.

The “all extremes are evidence” and “trends take 30 years” and “no weather event has ever contradicted AGW” story lines are conflicting and internally inconsistent. So long as we all understand that the compelling evidence is anecdotal storm stories, do unicorns and fairies come next?

If the objective here is to be persuasive you need to pick one of these conflicting stories and stick with it. Choosing the “no weather event contradicts AGW” is probably not productive.

Gareth June 23, 2010 at 6:34 pm

Terry: Seems to me you’re misrepresenting what climate scientists are saying (and indeed the point I’m making). Most weather events tell us little or nothing about climate change, because by definition most are clustered around the climatic average and changes in that average can only be discerned over long timescales. The changes in extremes, however, are seen to be taking place, and are evidence of a changing climate. If you read the Trenberth interview I link to, you’ll get a discussion of that point. Climate change shifts the probabilities of events, and you see that first in the extremes.

As for cold NH winters, you’ll have to wait for my post on that subject…

Macro June 23, 2010 at 7:55 pm

Perhaps the fact that NZ’s unique locality, which mitigates to some extent extremes in weather, hides from the “ordinary person in the street” (after they have been forced to evacuate their home due to flooding or mudslide or heavy snow fall) the fact that this is happening a bit more regularly than it did in the past.

bill June 23, 2010 at 8:55 pm

Terry @#38

So are most any warm day and cool day and wet day and dry day and windy day, at least in the press.

Not where I live (Australia)! A run of 27 days over 50C in Melbourne in September wouldn’t be sufficient for The Australian to suggest the event was consistent with AGW!

No one here is saying that ‘any’ weather is consistent with AGW – this is a classic straw man – but a hell of a lot of people were happy to claim the record US snow-storms disproved it!

We’re very clearly stating that no single weather event can be conclusively linked to AGW, but the models predict an increase in frequency of certain events, including intense inundation events, which, where it is cold enough, become snow storms. I thought it worth pointing out that while the storms were unprecedented in the record so was the global temperature at the same time!

An increase in frequency of any such predicted events thereby becomes part of the circumstantial case. I’ve provided a link to the Aussie BOM stating outright that it was reasonable to link an increase in high temperature records and concomitant decrease in low temp records to AGW.

Gareth has suggested – not unreasonably, surely? – that the world-wide spate of recent inundation events is also consistent, and something we may see more of in the future. He has not claimed that this ‘proves’ AGW. He has provided a link to an eminently qualified person suggesting the same thing on the basis of his study of US weather patterns.

I’m sure we’d all be interested to see any document put out by any BOM or similar institution that did track the frequency and intensity of dramatic rainfall events, regionally or globally, and their actual increase – or otherwise. Perhaps we’ll have to wait ’til AR5 for this overview!…

Steve Wrathall June 23, 2010 at 10:36 pm

“The changes in extremes, however, are seen to be taking place, and are evidence of a changing climate.”
You have nothing to say about reporting probability do you? There are today more people, with more camcorders & iphones and with more ability to broadcast their local flash flood/tornado etc than 20, 50 or 100 years ago and convince confused antipodeans that “something is happening”

You have absolutely no idea what trends in “extreme” weather events were in 19th century America, or the 15th century, or the 5th. But such knowledge is required before you can make pronouncements about “probabilities” of weather events and whether those probabilities are changing outside “normal” limits. As always the warmists make claims about things they do not and cannot know.

Just like a religion.

Macro June 23, 2010 at 11:33 pm

@42 Absolute tosh! Of course we don’t know every storm that ever occurred and nor need we know. But we do have are records from previous centuries. It may interest you to know that as far back as 1750 and before, seamen like Cook et al were keeping ships logs and recording in them the weather as they experienced it (and there were a significant number of HM ships wandering over the oceans for one reason or another). This admittedly anecdotal evidence was recorded and helped produce sailing guides for later sea-farers and constituted the Admiralties Notes to Sea Captains of the likelihood of storms in every ocean and at what time of the year. Still valuable today if your sailing from NZ to the islands for instance in the cyclone season. To say we have no knowledge of extreme events in previous centuries (and what really matters is since 1850) is utter nonsense.
(Retired Naval Officer)

Dappledwater June 24, 2010 at 1:24 am

Macro, just imagine how many more storms James Cook would have been able to report if he had an iphone or camcorder.

Steve Wrathall June 24, 2010 at 9:49 am

Hidden due to low comment rating. Click here to see.

bill June 24, 2010 at 3:26 pm

Poor old Steve – his abrasive persistence in channeling Dick Chaney has come back to bite him!

I will point out that Trenberth talks specifically about an increase in frequency and intensity of extreme rainfall events i the US, particularly since 1970, and the other article neither you nor Girma can apparently bother to actually read refers to an increase in intensity in Hurricanes over the 20th Century. So on information that CAN be known, yet again, the case apparently isn’t running your way!

You could always lower your high standards – as evidenced in strategically retreating during the Easterbrook fiasco; don’t think we’ve forgotten – and see if any data that can be known contradicts the ‘warmist’ hypothesis.

I assume #45 is an objection to censure? (I doubt it’s situationism!) No doubt this will confirm,yet again, that it’s all a religion; and that you, like Girma, are oppressed by those who would deny The Truth. It’s not that you routinely behave like a boor on another person’s blog where you’re actually a guest, is it, Steve?

Terry June 24, 2010 at 5:43 pm

Gareth, the AGW proponents choose which events to classify as extreme. At the moment there is no database setting forth a history of extreme events. One might be able to get a murky picture by looking at the last 150 years of news accounts, crop reports, weather records and other possible sources. Even that would leave a very skimpy record with evidence only available in a few areas. When the limited historic record is examined (hurricanes) there is no evidence of increasing extreme events.

Storms are often classed as a 1000 year event, but there are no records or evidence to support such a classification.

It is not that I don’t understand, it is that when someone tells me that this is a 1000 year event I want to see the records for the last 3000 to 5000 years. Given the relative lack of data for most of the world, there simply is no basis for declaring extremes if by extremes you mean events in the 1 percentile. As you well know, it may be improbable but certainly possible to have two or more events in the 1 percentile sequentially and then see many hundreds of events without another occurrence.

To the original point, when everything observable is evidence supporting a theory, what could go wrong?

Gareth June 24, 2010 at 5:59 pm

Terry: It’s not “AGW proponents” who produce the classification or estimate the probabilities and return periods for extreme events, it’s meteorologists and hydrologists. And there’s plenty of evidence available to support their classifications, either probabilistic (based on the instrumental record), or on other records (flood heights etc). Although it would be nice to have records going back thousands of years, you can estimate the probability of extreme events by setting them in the context of the distribution of similar events established over the instrumental record. What 1-1000, or 5000 means, effectively, is “very unusual indeed”. And if you see that sort of event happening more frequently than you might expect, then there’s a clear message.

C3P0 June 24, 2010 at 6:24 pm

Bill: “In the absence of a ‘control Earth’ to compare our high-CO2 world to we just have to make risk assessments based on probability”,

Sorry but we do have a control earth, its called history. And not just the last 100 years. Even if hurricanes have been increasing over the last 100 years (which is a debate I don’t want to get into in this thread), that does not prove that they haven’t gone through the same pattern from natural variation. Our understanding of weather 1,000 years ago, 10,000 years ago and 140,000 years ago is unfortunatly not strong enough at this point in time to conclude that the weather of the last 2 weeks is extrodinary.

bill June 24, 2010 at 10:27 pm

Ah, C3PO (@#49), because it is unknowable how frequently X occurred in the distant past then we cannot conclude either that X is occurring more frequently now – even if it may well be doing so on a scale of, say, the recent centuries that we might hope to actually measure – or even that that this is an undesirable thing and hence worthy of avoiding if we have any capacity to do so?

And while hypothesis Y predicts this increase in frequency of X, almost all of the other predictions of Y are being borne out before our eyes, and hypothesis Y also predicts an uncomfortable future for species H and planet Z generally, we are to understand that these uncertainties – unknowables, in fact – counsel only persistent inaction!

Is there a way in your world view, do you think, that anyone could gain sufficient information to justify pulling out of the trajectory that we’re currently locked in to? Or determine that the potential consequences of it are simply too dire to run the risk of proceeding? Because I don’t think there is. Of course you’ll say ‘yes’, but no level of actual evidence will ever meet that standard.

And it doesn’t strike you that it’s a teensy-weensy bit inconsistent to cite ‘history’ as our ‘control Earth’ – so we can doubtlessly be warmly confident this has all happened some time before and hence can’t be threatening – at the same time as insisting that the fact that we don’t (and actually cannot ) know all of what has happened before justifies persistent inaction?

Macro June 25, 2010 at 9:04 pm

Just read this:
“The German reinsurers Munich Re state that the economic losses from natural disasters increased eightfold from the sixties to the nineties. About 80% of this resulted from extreme weather-related events. The company now predicts that by 2065, damages will outstrip global assets. Insurers of the UN Environment Programme believe worldwide losses linked specifically to climate change will reach a yearly $NZ360 billion in 50 years time.” The Constant Economy 2009 Zac Goldsmith. (Conservative MP for Richmond Park London)

bill June 26, 2010 at 3:51 pm

I’d forgotten how many insurance giants are now in on the conspiracy!

And then there’s this from meteorologist Jeff Masters

We’ve now had six countries in Asia and Africa that have beaten their all-time hottest temperature record during the past two months. As I discussed in my blog about Pakistan’s May 26 record, Southeast Asia also had its all-time hottest temperature in May, when the mercury hit 47°C (116.6°F) in Myinmu, Myanmar on May 12. All of these records are unofficial, and will need to be certified by the World Meteorological Organization (WMO). According to Chris Burt, author of Extreme Weather, setting four national heat records in one month is not unprecedented–in August 2003, five countries (the UK, France, Portugal, Germany, Switzerland, and Liechtenstein) all broke their all-time heat records during that year’s notorious summer heat wave. Fortunately, the residents of the countries affected by this week’s heat wave are more adapted to extreme high temperatures, and we are not seeing the kind of death tolls experienced during the 2003 European heat wave (30,000 killed.) This week’s heat wave in Africa and the Middle East is partially a consequence of the fact that Earth has now seen three straight months with its warmest temperatures on record, according to NOAA’s National Climatic Data Center. It will be interesting to see if the demise of El Niño in May will keep June from becoming the globe’s fourth straight warmest month on record.

I found this in the context of Joe Romm’s latest post on the distribution of extreme weather events in the US. (Guess which way they’ve headed!)

I’ve also just been reading the opening chapter of McKibben’s Eaarth – which takes the reader through a genuinely horrible litany of just such instances of ‘extreme’ becoming the new ‘normal’. His argument that we now live on Earth 2.0, having left the more benign and familiar Earth 1 behind, only seems to gained more weight since publication.

So, come on, Pollyannas, the Cassandras are beating you hands down! What can you offer to counter all this? Anything? Beyond some benighted commitment to the centrality of doubt and the conservation of some economic ideology ranking above the conservation of the planet itself? Failing to act is starting the look like straight maladaptation, isn’t it – the ultimate sin any species can commit?

To borrow an idea from another blog posting I saw recently – I apologise for not recalling where – it’s like some cosmic villain has lashed the planet to the railroad tracks, and you guys just want to debate the rail timetable!

Gareth July 1, 2010 at 11:05 pm

I had an interesting chat last night with someone who had recently spoken to a senior French meteorologist. They had naturally discussed the Var flash flooding mentioned in my first paragraph. In the 24 hours when most rain fell, the total was 400mm — double the previous record. Suggestive, n’est-ce-pas?

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