Exclusive interview: NCAR’s Trenberth on the link between global warming and extreme deluges

New England, Tennessee, Oklahoma…. Who’s next?

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 now-a-days because of the fact that there is this extra water vapor 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.

That’s Dr. Kevin Trenberth, head of the Climate Analysis Section at the National Center for Atmospheric Research, on the warming-deluge connection.  I interviewed him a couple weeks ago about Tennessee’s 1000-year deluge aka Nashville’s ‘Katrina’.

The latest record-smashing superstorm makes his comments even more timely — see Capital Climate’s “Oklahoma City Paralyzed By Flash Floods.”  As with Tennessee, New England, and Georgia, what makes OK’s deluge doubly remarkable is that it was not the remnant of a tropical storm (see “Weather Channel expert on Georgia’s record-smashing global-warming-type deluge“).

Here is the audio (plus transcript) of the interview with one of the country leading scientific authorities on climate change and extreme weather:

Part I:  [audio:]

Part II:  [audio:]

Note:  I sent the transcript to Dr. Trenberth, so it has been corrected in a couple of places.  You can find links to the studies Dr. Trenberth refers to here:  “Northeast hit by record global-warming-type deluge.”  Before the interview, I sent him this jaw-dropping figure (explained here):

Nashville1 5-10

Joseph Romm: I wanted to talk mostly about this Tennessee rain storm which didn’t get a lot of attention. And the potential link to global warming got virtually no attention at all. I sent you this link that the National Weather Service and NOAA put together of just how extreme an event it was.

Kevin Trenberth: Yes I just looked at it.

JR: This seems astounding to me. I’ve never seen anything like this. I’d just be interested in your thoughts on the unprecedented nature of this storm, and how you would characterize it in an age where scientists predicted as we warmed we’d get these kind of extreme deluges.

KT: That’s indeed true and that’s consistent with the expectations with regards to global warming. It’s also consistent with things that we’ve already seen “¦ including happening in the US. So there was a study a few years ago now, that only went through 2002 but it was looking at the 20th century and at that point the average rainfall over the 48 contiguous states had gone up 7% but the heavy rainfall events had gone up 20%. And so the heavy rainfall events have been documented as increasing across the United States.

There was a more recent study that looked at somewhat different statistics and showed that 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]. And indeed most of those changes have occurred since about 1970.

Now the physical cause for this is very much related to the water vapor that flows into these storms. And these kinds of storms, well all storms for that matter, reach out on average — this is very much a gross average — about 4 times the radius or 16 times the area of the region that’s precipitating, the rain. And for these kinds of storms a lot of the moisture is coming out of the sub-tropical Atlantic and even the tropical Atlantic; some of it comes out of the Gulf of Mexico. And so the moisture actually travels about 2000 miles where it gets caught up in these storms and then it rains down. And the key thing is, that in the tropical and sub-tropical Atlantic the sea temperatures are at very high levels and in fact they’re the highest on record at the moment right in the eastern tropical Atlantic. It’s going to be interesting to see what that does for this hurricane season coming up.

For every one degree Fahrenheit increase in sea temperature, the water holding capacity for the atmosphere goes up by 4%. And since the 1970’s on average there’s about a 4% increase in water vapor over the Atlantic Ocean and when that gets caught into a storm, it invigorates the storm so the storm itself changes, and that can easily double the influence of that water vapor and so you can get up to an 8% increase, straight from the amount of water vapor that’s sort of hanging around in the atmosphere. This is reasonably well established.

And so then, when you have the right conditions, and in the spring time, these conditions tend to occur, and the storm stalls a little bit (it ran up against a roadblock for a while), then this is one of the consequences.

So although a lot of aspects of this is the sort of thing that happens is weather and natural variability, one could easily argue that up to about a 10% enhancement of this is associated with global warming. And possibly even more in terms of some of the other things that are going on but which are much harder to pin down. So that’s the link.

It’s directly related to the fact that there’s more water vapor in the atmosphere. There’s warmer sea temperatures over the ocean that provide that moisture in the atmosphere. And then the right storm comes along, the right conditions, especially slow moving, and bingo.

JR: Stu Ostro, the senior meteorologist of the Weather Channel, he wrote a post on the storm that hit Georgia in the fall, and he talked about the atmospheric warming resulting in increase in the 1000 to 500 millibar thickness creating “¦ basically an increase in 500 millibar heights.

KT: Right, It’s warmer in the lower half of the atmosphere, yes.

JR: This, what he called, “exceptionally strong ridges of high pressure sometimes accompanied by strong, persistent cut off flows”¦. So this is sort of another aspect of the climate change.

KT: Yes, The change in the storm tracks, or the change in the weather patterns is an aspect of it. That’s a little harder to pin down as directly relating to global warming. There might be some natural variability aspects to that, but you’ve only got to look around and so last year, if my memory serves me right, there was extensive flooding along the Mississippi River, and they were talking about 500 year storms, and yet in 1993 they had similar flooding along the Mississippi River, and again they were talking about 500 year storms. Here you are having these 500 year storms so to speak in slightly different areas but at the same time of year. This is a part of a pattern that exists.

We’ve seen other examples out in Seattle last year, and also of course the flooding in New England and the exceptionally heavy snow storms in Washington DC this year“¦. The same mechanism actually applies to the heavy snow, all you have to do is have the right weather conditions and for it to be cold enough and this precipitation just turns into snow. The very heavy snowfall amounts are actually related to the fact that the moisture that’s coming into that region is coming off of the tropical or sub tropical Atlantic where there’s abundant moisture and more moisture than there used to be: demonstrably more moisture than there used to be 30 years ago. So there’s a number of other examples you can point to as well.

JR: It seems to me the media hasn’t figured out a way to talk about this so they often just don’t talk about it at all.

KT: That’s correct.

JR: And as a result the public never learns the connection to climate change. I’m just wondering if you have any comments about that and what you would suggest is the right way to talk about it and the like.

KT: 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 now-a-days because of the fact that there is this extra water vapor 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.

JR: So would you recommend”¦.  I certainly try to write about this, and I use phrases like “consistent with,” which is something the Royal Academy has used [see “Must re-read statement from UK’s Royal Society and Met Office on the connection between global warming and extreme weather“] or “global warming sets the table for these events” [from Weather Channel’s Ostro] what’s sort of your preferred way of saying given that you don’t want to say any one weather event was caused by global warming?

KT: That’s right and so the weather events happened, the spring storms happen, you certainly expect these kinds of things at this time of year, but the odds are that when these happen getting flooding out of them is increasing substantially. And most of the time, even if there is this modest increase of say 5% or 5% to 10%, it’s still within the realm of natural variability frequently, but every so often you go outside of the realm of natural variability and that’s how you get these 100, 500, 1000 year storm events that are occurring. And so this becomes the straw that breaks the camel’s back. Were just seeing more and more instances of that and the odds of that kind of thing happening are increasing.

JR:  Yes, “Straw that breaks the camels back” is a phrase you used about Katrina as I recall.

KT: Again it’s the same sort of thing, where there’s an enhancement, there’s a global warming component. You can argue that it’s not the dominant component, especially on an individual storm like Katrina. But then in the 2005 season was just so exceptional, we had all these storms that went off in to the Greek alphabet, there was Rita and Wilma. Wilma, the strongest recorded storm on record. And Ophelia, that year, that churned around for 3 or 4 days right off of there coast of the Carolinas there. So it was not any individual storm there that you would really want to point to, but all these storms collectively are a clear indication that there was a warming component and at that points to the sea temperatures in the Gulf, and the Caribbean and in the tropical Atlantic which were by far the highest on record, and they were the fuel for that. As I say, this year in the Eastern Atlantic it’s even higher than that. But this year the Caribbean and the Gulf are somewhat cooler than average, and so how this hurricane season pans out is going to be an interesting one to see. But those are the factors that come into play.

JR:  We’ve only warmed a little bit so far compared to what some of the models project. If we don’t reserve emissions trends soon, what kind of storms are we looking at in a few decades?

KT: The key number is this number in this case, which is pretty rock solid. For a one degree Fahrenheit increase in air temperature the water holding capacity goes up by four percent. Pretty close to four percent. And so if the sea temperatures go up by one degree, as they have, then the air temperatures probably go up a little bit more than that in fact. And so when you start talking about three, four, five degrees then you’re talking about twenty percent increases in the water vapor in the atmosphere.

The way in which we think this is going to happen is that the intervals between storms will be longer, but then when you do have the storms they are apt to be a doozie. When it rains it pours, so to speak. So you can really get deluges, and there are times when you have longer dry spells in between so there’s the risk of drought if you happen to miss these storms. And they are very much of a hit and miss nature. But then when you do get hit by them suddenly you’ve got a deluge.

And so this is a real challenge as to how you deal with that from a water management standpoint, from a drainage standpoint. In some sense, when this happens you’ve got all this water there, and water can actually be a valuable resource if you can put it into a reservoir, or a lake or something like that where you can use it in the future: it actually gets transitioned to a valuable resource. In the mean time, some of it just inundates areas and causes a major problem. And that relates to what kind of drainage systems you have, what kind of culverts you have. One of the ways in which city councils and the Corp of Engineers manage these things is to always build structures to deal with these things. But another key part of it is: can you put the water somewhere where you can use it in the future? Because these longer dry spells in between times are something else you’re going to have to contend with.

JR:  Yeah and the issue is, of course, the rain when it comes down in the deluges , it overwhelms the capacity of the storm drainage and you get these runoff”¦ We have so many combined sewage/storm water systems, we may have to rethink that”¦

KT: If they’re combined in that nature then you have water quality problems and you can get disease and cholera and things like that which can come out of that kind of situation. It’s the same thing even in open fields, that a lot more water gets transported across the surface of the field, and so all of the feces from animals can contaminate the water and cause various kinds of water contamination problems.

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56 Responses to Exclusive interview: NCAR’s Trenberth on the link between global warming and extreme deluges

  1. homunq says:

    I’d love to see the same map for OK. Apparently, local residents remember a flash flood from 1968, before records were kept – though it’s not certain how the two floods compare. But 1000 years is also before records were kept, so there must be a way to estimate ARI without having records back that far.

    Still, I suspect that the OK flood was less record-shattering. Perhaps “only” a 100 or 500 year flood at its center.

  2. prokaryote says:

    “The way in which we think this is going to happen is that the intervals between storms will be longer”

    I’d like to see some studies/stats on related weather event flux. My impression from following the news, is that intervals for storms with torrential rain becomes shorter.

  3. prokaryote says:

    From a global perspective.

  4. The Wonderer says:

    Is this translating to record dew point readings? Seems like a more direct measure to use than all the percentages you’re throwing around, and which will cause everyone’s eyes to glaze over. Not that dew points won’t too.

  5. David says:

    Don’t forget about the deadly Arkansas flash floods too!

    And I’m not surprised by the purported link between these flash flooding and global warming… it’s pretty clear that these types of events have been increasing in frequency in recent years.

  6. Steve Bloom says:

    Excellent interview, Joe, and thanks to Dr. Trenberth for taking the time. More like this, please!

    Some background, then a question:

    Dr. Trenberth refers to the idea (more or less the scientific consensus, at least as of a few months ago) that as warming progresses we can expect fewer but stronger tropical cyclones. A few weeks ago, Kerry Emanuel of MIT, fair to say the leading TC theoretician, came out with a paper saying that the consensus is wrong, that in fact we should expect not just stronger but more frequent TCs.

    What was most interesting to me is that Emanuel says the consensus is wrong because of something that sounds quite obvious — a failure of the GCMs (the ones used for TC projections, anyway) to account for the (measured) cooling lower stratosphere. Since TCs can be thought of as heat engines and as such their efficiency is related to the temperature difference between their bottoms (at the sea surface) and tops (at the tropopause that forms the boundary with the stratosphere), efficiency is increased when the latter decreases. More efficent storms can then be expected to form, strengthen and survive more easily.

    Emanuel further calculates the expected North Atlantic TC behavior of the last few decades using the corrected efficiency and finds an excellent match with the record. Prior similar attempts using sea surface temperatures found only an approximate relationship.

    So, what does Dr. Trenberth think of this new result (albeit that there hasn’t been time for it to be peer-reviewed)?

    (PS — AMS just added audio with slides of Emanuel’s presentation at the same link as above. He mentions that Tom Knutson of GFDL, whose model results were the principal basis for the recent consensus, is getting the same result using a different method. Also, listen for a “hide the decline” joke.)

  7. Steve Bloom says:

    Joe, I have a comment with a link in moderation. TIA.

  8. Aaron Lewis says:

    Sounds more anecdotal than a systematic study! We need good numbers! NWS seems not to want to crunch the numbers.

  9. Leif says:

    In February we discussed this 4% number and the question was asked, How much water does 4 % translate to?

    johna, @14 came back with calculations that the volume of water is ~1.5 times the volume if water in Lake Superior. It would be nice to get confirmation on this calculation by others so that we could use the simile with more confidence. If the 4% = ~1.5 Lake Superior holds, then 20% would equate to about 8 extra Lake Superiors floating around looking for a place to land. Three times Lake Superior in 40 years, by 2050.

    Are you reading this, Senator Inhofe?

  10. catman306 says:

    Excellent posting, Joe. Thanks.

    Climate really just means the annual tendencies of weather parameters. Tell people that the weather tendencies are changing. ‘Climate change’ has gotten such a bad rep in the media. So don’t even mention climate.

    You can alter climate changing behavior without mentioning climate.

    (Yes, I realize that this is how right wing conservatives play their game and playing it makes me dizzy.)

  11. Douglas says:

    Aren’t most rain gauges in urban areas? This is just a product of the Urban Rain Funnel effect.

    (Sorry…morbid humor…long day)

  12. prokaryote says:

    With more rain/flood there is a decompose process feedback.

  13. Is the general trend more precipitation in the northern hemisphere and less in the southern? Is it the same in both hemispheres? This was not clear to me in the interview.

  14. Chad says:

    Visited my parents in rural northern Michigan last weekend. A storm hit Friday night, dumped 8 inches of rain in 2.5 hours, and gave us a nice 100-year flood. We lost 75% of our towns Historical Society’s collection, which was temporarily in the library basement during a remodel. Over six feet of water flooded a place that had never been flooded in anyone’s memory.

    Of course, my Limbaugh-loving dad refuses to see any connection between his behaviors and the both hot and freaky weather that just keeps coming and coming.

  15. jyyh says:

    #13 Richard: Since most of evaporation (per area) happens in the intertropical convergence zone that is currently located a bit more time in the northern hemisphere because of the imbalance of arctic melt vs antarctic melt (I think) there should be a slight bit more increase in the precipitation in the northern hemisphere than in the southern one. I’m not saying Madagascarian tropical storms would not grow in this respect, nor that Australian ones aren’t.

  16. Bob G. says:

    This is outstanding stuff, which absolutely deserves more media coverage. Perhaps Trenberth could write an op-ed piece that one of the mainstream publications would run. I say, submit it to the Post, noting how they have run the pieces by Palin, and implicitly dare them not to run a piece by such a highly credentialed scientist. Sure, perhaps they won’t run it. But it’s worth a shot. As a former newspaper journalist, I will tell you that this is a legitimate story, a good story, by the classic standards of journalism.

  17. The latest and greatest summary of tropical storm research is
    Tropical Cyclones and Climate Change (now with supplemental info) by Knutson et al. (2010). It can be viewed freely. :)

    Scott A. Mandia, Professor of Physical Sciences
    Selden, NY
    My Global Warming Blog

  18. paulm says:

    Have to agree with you #2 p. If you have 100, 500 & 1000yr events occurring every couple of years I think the frequency has increased wouldn’t you say!

    …”JR: We’ve only warmed a little bit so far compared to what some of the models project. If we don’t reserve emissions trends soon, what kind of storms are we looking at in a few decades?”

    Is this a little bit of a hedge, Joe. Aren’t we going to see bigger impacts even if emissions were zeroed today? How much Global temp is in the pipeline now…1.5C?

    So we still talk about these extreme events as probabilities. Well, if we did not have Global Warming then these events would not be occurring globally in the current pattern, period. I think its safe to apply that binary to the deluges we are seeing world wide and region wide.

    So we can safely say that GW is causing these events. Now, can we say GW has cause a specific event. I think we can. We have a sequence or pattern of events which is attributed directly to GW. Having established this, each incidence which falls within this pattern is more likely to be cause by the forcing than not. Therefore, in generally we can attribute the specific event to have been caused by GW.

  19. Steve Bloom says:

    Re #17: Scott, that’s the consensus that now lies in ruins as I described in #6. Talk about the ink not even having a chance to dry…

  20. Bill W says:

    I’d say somebody should point this out to Senator Inhofe (R-OK/OIL), but he’d probably just dismiss it since Trenberth’s name shows up in the CRU emails.

  21. Our news media is completely bought off and intimidated into compliance and ignorance.

    Journalist Ross Gelbspan supported this notion in his posting: “U.S. Press Coverage of the Climate Crisis: A Damning Failure of Courage”:

    “Given the dramatic increase of extreme weather events – you would think that journalists, in covering these stories, would include the line: “Scientists associate this pattern of violent weather with global warming.” They don’t.

    A few years ago I asked a top editor at CNN why, given the increasing proportion of news budgets dedicated to extreme weather, they did not make this connection. He told me, “We did. Once.” But it triggered a barrage of complaints from oil companies and automakers who threatened to withdraw all their ads from CNN if the network continued to connect weather extremes to global warming. Basically the industry intimidated CNN into dropping the one connection to which the average viewer could most easily relate.”

  22. Peter Houlihan says:

    There were also very serious floods in central Europe early this month.

    Hungary, Slovakia, Romania, and Poland were particularly hard hit. In this case it was the result of persistent rains for over a month long period. The northeastern part of Hungary had as much rainfall in a one month period as they typically have over one year.

  23. jyyh says:

    #18 #6 Steve Bloom: Interesting way of describing a tropical cyclone, the heat engine I mean. This is probably the wrong place to ask but could this description be used to simplify this aspect of weather in GCMs?

  24. Peter Mizla says:

    We had extreme deluges here in New England in March, in parts of Connecticut we had a record amount of rain for the month-around 16″.

    The eastern and south eastern part of the state suffered the most- New Hampshire also was hit by historic flooding.

    Last week we had weird weather- a heat wave followed by two tornado warnings. Then a few days later- extreme downpours in cool weather- followed by 2 more tornado warnings and destructive storms with trees uprooted and utility poles downed. I have noticed over the last few years the increasing torrential downpours here- something we had far less of 30 years ago.

    Another heat wave at the end of the week- with 90 or above- June should turn out to be the 6th warmer then average month in a row,

    The Meteorologists here are at a lost for the reasons we had cool temperatures and tornado warnings- ‘saying the atmosphere had unusual unstable conditions…..

  25. Peter Mizla says:

    Also I agree that the MEDIA is not relating the real news about the increasingly strange weather.

    The extreme fringes of the far right- have much to do about suppressing information.

    The media companies all need advertising revenue- and many companies have a right wing agenda–even the New York Times is at fault- with their biased reporting about climate change in the tri state region.

  26. Whatshisname says:

    Ten inches of rain fell in two hours in the New Braunfels, TX, area between Austin and San Antonio overnight June 9. I don’t know if that adds to this discussion because sudden deluges are not unheard-of in the Texas Hill Country. Despite its severity (there was one fatality), the event didn’t merit “rain bomb” status in the news either. On the other hand, although flood gauges along creeks and streams throughout the region are wired for instant warnings, this deluge sneaked up on people, especially on the Guadalupe River. In fact it was a day or two before Austin news outlets fully realized the flood’s severity, which in itself is highly unusual because the weather is given such a high priority in these parts. Moreover, the night before the flood, all of the television forecasters in Austin reported the weather service was torn between issuing a flash flood watch and simply putting a slight risk of rain in the forecast.

  27. Anonymous says:

    Peter Houlihan, 22# “There were also very serious floods in central Europe early this month.”

    Austria too, and have a look for “torrential rain”.

  28. prokaryote says:

    Farmers worldwide can help with carbon negative action. Remove carbon from the air – plant trees(new carbon sink), make biochar, preserve existing carbon sinks.

    In return renewable devices for the 3rd-world, so that they do not start with co2 technology(What most scenarios expect). This also helps stabilize world food production and with biochar you require less fertilizer.

    If we at the same time phase out co2 emissions in the developed word and replace it with clean energy (zero or negative carbon) we get a new motor for a new economy.

    If there are better plans i like to hear them.

  29. Chris Dudley says:

    I addition to a way to talk about warming’s role in individual events (Joe’s warming-type event is a good try) we need a ticker on the costs of warming. How many people have died? How much property has been lost? How many opportunities have been foregone? This may be easier than the interface with individual events because the ensemble of events may be treated statistically but there are many confounding factors as well. For example, even if we could assign a clear fraction of the cost of Katrina to warming, it feels as though the cost has not been fully counted since so much of the damage has not been repaired.

  30. Steve, yes I saw your post but that is one new paper so I would hesitate to claim that the consensus is shattered. I have always wondered if a warmer world would lead to more frequent, more intense, and longer El Ninos. El Ninos increase shear in the Atlantic tropical basin and inhibit storm growth. If so, then there could very well be fewer hurricanes in the Atlantic. ENSO simulation is still a model weakness, I believe.

    Regardless, it does appear that stronger hurricanes are going to become more common in a warmer world.

    Scott A. Mandia, Professor of Physical Sciences
    Selden, NY
    Global Warming: Man or Myth?
    My Global Warming Blog

  31. This is an important interview–many thanks for it. My sense in talking in quite a few places is that this is one aspect of climate change people are really starting to get. I’ll sometimes ask if there are municipal officials in an audience, and if there are ask them how their 100-year-storm planning is coming. Rueful chuckles. They all already understand that they’re facing very real and very expensive infrastructure trouble.

  32. Raul says: has and others have booyah systems in the Arctic that indicate
    wind patterns have changed. Also if the sea ice is melt then the warmer
    air and water temps also change the Arctic humidity measurements.
    With changing wind patterns and humidity the Arctic has changed how
    it interacts with other climate patterns?

  33. Paulm says:

    Whos next – Bangladesh!

    It would be nice to see a ‘discussion’ between climate scientist and mets now in a public fourm.
    I think they are finally comming round now, due speciffically to deluge(as are many of the public).

    Just goes to show that events drive belief.

  34. Scott Smith says:

    Permanent droughts. Irreversible. Looks like it was rhetoric which is easily reversible.

    [JR: Huh? Global warming causes more weather extremes. When it gets hotter, dry areas will tend to get drier, and that’s not even counting the expansion of the subtropics. But wet areas are likely to get wetter and when it does come down, it pours, as they say.]

  35. Leif says:

    Scott, @30: “I have always wondered if a warmer world would lead to more frequent, more intense, and longer El Ninos. El Ninos increase shear in the Atlantic tropical basin and inhibit storm growth.”

    El Nino is a function of the ocean’s response to uneven heating in my view and as such must have a significant lag response time built into itself. The atmosphere on the other hand responds much faster to uneven heating and cooling. Perhaps much “larger” high or low pressure systems will develop with more “staying” power are in store. Recall the “Frankinstorm” or the eastern US cold and snow event of this winter? The cold event in Mongolia that froze over 4 million live stock this winter? The Intensity of local events as witnessed by recent flash floods? Perhaps we will see Jet Streams with intensified vigor, flatter, amplified, or shifted appearances.
    One thing for sure is that there is a lot more energy in the system than humanity has ever witnessed and we have no bench marks for what to expect. Expect the unexpected, IMO.

  36. Colorado Bob says:


    TYLER TX 1.71 IN 1974 8.14 IN 2010 RECORDS SINCE 1896

    MAY 24…2010.

  37. RoySV says:

    Another case I don’t see mentioned
    Floods Kill 40+ on Portuguese Island of Madeira

  38. Colorado Bob says:

    I was in Estes Park during the Big Thompson flood in 1976 , and I spoke with Gary P. Nunn who lives at Marble Falls , Texas where 18 inches fell in 6 hours just 3 years ago.

    Our advice for folks when on of these comes …….
    You better be on high ground.

  39. Colorado Bob says:

    The Del Rio number is interesting , it marks the wettest Jan. to May period in the record. That fits with the current pattern all along the Gulf , and inland . Dec. 2009, was the wettest month ever recorded at New Orleans. The list is really getting to be impressive.

  40. Steve Bloom says:

    Re #30: Well, Scott, without the leading TC modeler and leading TC theoretician it doesn’t seem like much of a consensus to me. I agree with your first paper hesitancy, but the nature of this breakthrough (something fundamental having been missed by prior work) makes me think otherwise. Also, regarding a future El Nino-like state, it’s not expected to have exactly the same characteristics as the ones we experience now. I don’t recall the details, but I think Emanuel and colleagues have discussed that issue in their papers anticipating much higher TC activity in a mid-Pliocene-like future.

    Anyway, since an immediate implication of Emanuel’s work is that we very much can expect more seasons like 2005 in the near future (bearing in mind that they probably still won’t be exactly common since a confluence of factors is needed for them to occur — rather like this year, now that I mention it), I wonder why the press isn’t already picking up on this.

    Re #23: jyyh, that sounds right to me, but the basic problem with GCMs modeling TCs is that the TCs are still much too small relative to the model grid scale. The TC modeling that gets done uses a nesting technique that involves a regional-scale model (with a much tighter grid) that’s pasted into a small area of the GCM and moves with the modeled TC. As I understand it this is thought to be less than ideal. Eventually the GCM scale will get down to the needed detail to show TCs directly, but that won’t be for some years yet.

  41. Christine says:

    Weird weather up here on the Canadian prairies, too – a torrential downpour several weekends ago left southern Manitoba swamped, one town declared a state of emergency.–systems-95246059.html

  42. paulm says:

    Record Flooding is Pearl Harbor Moment for Climate Change

    “Political leaders must start to connect the dots between these catastrophic floods and our failure to reduce the level of CO2 in the atmosphere. The longer we wait to address the problem, the more frequent these horrific disasters will become.

    We have two choices: Move away from fossil fuels, or move to higher ground.”

  43. Oklahoma City broke their all-time daily rainfall record. That’s a once in 43800 days event (365 days * 120 years).

  44. Colorado Bob says:

    NOAA: May Global Temperature is Warmest on Record
    Spring and January-May also post record breaking temps

    June 15, 2010

  45. Steve Bloom says:

    For those interested in the TC stuff mentioned above, I expect the current post at Real Climate will be informative. At the start, it appears that Kerry Emanuel’s new paper is news to some people for whom I am very surprised it’s news (e.g. Gavin Schmidt). Perhaps Kerry, similar to a certain fictional Soviet leader, likes surprises.

  46. dhogaza says:

    To add to the weather news, northern spain had heavily flooding last week.

  47. Steve Bloom says:

    Scott, here’s the most recent paper on Pliocene TC activity (with implication for a similarly warm future climate). It addresses the El Nino issue directly.

  48. John Atkeison says:

    Thanks for the great interview and good discussion!

    Here on the Gulf Coast, we are in high anxiety mode. One of the many things we wonder about is how far will the poisonous crude and “dispersant” move inland. The storm surges in 2005 and other years went miles inland. (One inland “puddle lake” after Gustav in 2008 stayed for months, too.) Moisture from the Gulf flows over a huge portion of the country, including Albuquerque, NM where my grandbabies live. Is anyone measuring this? Do we really know what the odds are that poisons will travel ”x miles under ‘y’ conditions?

    We are constantly hearing stories of idle cleanup crews and boats, and their rapid deployment for Obama’s visits, and their equally rapid dispersal afterwards. This experience and the semi-intentionally bungled Katrina response don’t make us optimistic.

    No matter what year you use when you start counting up the cost of Global Warming it is more than humanity can possibly afford by any measure. We as a country flunk the response test.

    It is time to kick ass and force a change in course. The President has the only power that can change things, IMHO, which is the ability to mobilize huge numbers of Americans. … Surely we don’t think that the folks who have presided over the creation of this crisis are the best ones to clear it up? Well, not without a row of pitchforks in their backs!

    This rant is to say, “This is the moment that we can change course by more than is usually possible– let’s not miss the chance!”

    Thanks for listening.

  49. prokaryote says:

    More on current Floods

    The Chinese government has said that severe seasonal flooding in the country has displaced over a million people and killed at least 155.

    According to the Office of Flood Control and Drought Relief Headquarters, the southeastern parts of China were hit the worst. 1.3 million people were forced to temporary shelters after 140,000 homes collapsed, mostly in the provinces of Hunan and Jiangxi.

    The office reports that direct economic losses from the disaster reach 24 billion yuan, or about US$6.5 billion, and that the figure is 370% higher than the damage caused by last year’s seasonal rains.

    The rainy season in eastern China is in June through August; flooding is frequent, and causes mudslides and deaths. This year, however, rainfall totals appear to be the highest they have been in over ten years.,_kills_dozens?dpl_id=191261

    Outlook – more rain.

  50. #47 Steve:

    I cannot believe I missed this paper. Fig. 2 is going to be one that I will be using in my upcoming Impacts series of pages. That figure is a real eye-opener if it is even half-correct.

    The key for me is the statement: GCM calculations show an atmospheric circulation for the early Pliocene with weaker (meridional) Hadley and (zonal) Walker cells—the weakened atmospheric circulation implies reduced vertical wind shear, which is favourable for tropical cyclones.

    Also interesting how their analysis shows TCs as a driver of ENSO and not the other way around during the Pliocene. Who would have thought?

    Thanks again for the link. Isn’t the Web great?

    Scott A. Mandia, Professor of Physical Sciences
    Selden, NY
    My Global Warming Blog

  51. Paul Young says:

    Down near the bottom of the world in New Zealand we’ve recently had some extreme rainfall setting new records too:

  52. jyyh says:

    on the news: southern France has had deadly floods from the rains in the western Alps.

  53. Steve Bloom says:

    Re #51: Scott, I’m speculating, but it may be that what set Kerry off on the path of looking for a missing X-factor to explain recent TC trends was the conclusion (reflected in the consensus paper) that frequency should be expected to go down with continued warming, which is hard to reconcile with his Pliocene results. Of course there’s also the fact that prior efforts (including his own) to explain TC trends haven’t gotten very good correlations.

    It’s very interesting to get a look at science in action, e.g. Kerry’s remark that until six months ago he had no idea that there was a discrepancy between lower strat temps the models and measurements (although I wish Gavin would clarify what seems to be his contrary view — I suppose we have our denialist friends to thank for what may be a hesitancy to have such discussions in public).

    Finally, while I’m pleased to note that that RC thread has far and away the highest scientist-to-comment ratio in the history of the blog (inc. two Rossby Medal winners!), I’m surprised to see how little interest there is from others. This is comprehensible, interesting science with important real world implications, so what’s not to like?

  54. Susan Anderson says:

    Thanks for a great article and comments. I’m not a scientist, but observant, and with a long history of varied contacts (including drawing instructor at MIT!) with science and scientists. It seems to me a little odd that it is not obvious to anyone who has been following world weather for a few decades that there is an increase in both intensity and frequency. I realize that my ignorance is showing, but sometimes it is odd that science diverges from what seems obvious to my untutored recordkeeping.

    Am I wrong? Is my bias showing?

    In the ongoing argument, given American lack of competence in understanding the process and results of science, it is important to point out events people can observe for themselves. It is interesting that the intensity of denial has reached the point where people are encouraged to look the other way when floods and storms occur. I know some of this is wishful thinking, but one would think people would begin to notice as the wolf gets closer to their door.