The Weekend Wonk: Kevin Trenberth on the Coming El Nino, Part 1

May 11, 2014

In putting together this month’s video on the impending El Nino, I interviewed Dr. Kevin Trenberth at length.

I wasn’t able to fit everything in the short vid, but there is so much good stuff here, I thought it would be a shame not to share.

Part 2, and a bold prediction, tomorrow.

16 Responses to “The Weekend Wonk: Kevin Trenberth on the Coming El Nino, Part 1”

  1. dumboldguy Says:

    I like Trenberth—-patient, understandable, willing to tell it like it is—-hurry up with the rest of it—-can’t wait to hear the BOLD prediction. Because it’s BOLD, does that mean it will move away from the “… single weather event can be blamed on AGW….” BS that we hear too much of and makes me so crazy?

    Speaking of scientists who are enjoyable to watch and learn from, what is Jason Box up to and what’s the status of Dark Snow 2014?

  2. […] In putting together this month's video on the impending El Nino, I interviewed Dr. Kevin Trenberth at length. I wasn't able to fit everything in the short vid, but there is so much good stuff here,…  […]

  3. redskylite Says:

    Well and simply explained in plain language, by the New Zealand born climate researcher, and was certainly appreciated by me.

    What did make me think was some of the sea level rises he talked about, 1.70 mm per year (NASA) does not sound very serious or immediately threatening, but that is an average, he was talking of 20 cm in the Western Pacific and 10cm in central and Eastern pacific and a drop elsewhere. Many people (including me at one time) visualize an equal rise uniformly spread around the oceans. I too look forward to tomorrow’s part 2 including the bold prediction.

    • greenman3610 Says:

      differing rates of sea level rise are counter intuitive, but nevertheless true.
      The East coast of the US has one of the highest rates on the planet.

    • One point that is unclear to me is whether the rise in local sea levels which he is speaking of are part of the general rise in sea level associated with global warming, plus the changes that are largely due to changes in ocean circulation, or whether he is speaking of the changes that are associated with ENSO, where the warmer part of the Pacific will be higher and the cooler parts lower. It seems as if he going back and forth between the two.

      Now I realize that we may see ocean levels fall, something we had during the latter half of 2010 when sea levels fell by about 6 mm, although I understand this was largely due to so much water raining out of the oceans on to the continents as we transitioned from a moderate El Nino to the La Nina, but sea levels had essentially regressed to the trend by 2012 as the water drained off of the continents. But this obviously isn’t what he is talking about.


      • greenman3610 Says:

        you’re overthinking.
        sea level is rising overall.
        some places are rising faster than others.
        some places winds and currents are moving water around, and it piles up temporarily.
        think of it like the waves in your bathtub as it fills up.

      • dumboldguy Says:

        The global long-term AVERAGE sea level has been going up at a uniform and now accelerating rate. And everyone (with a brain) agrees that AGW is the cause.

        Trenbreth was talking about all the various more LOCAL and REGIONAL sea level rise effects—-they can be due to winds, currents, thermal expansion, salinity and density changes, and land subsidence. Yes, he “went back and forth” and mixed it all together, because the oceans and atmosphere are fluids and behave dynamically as such. Peter is right when he says to not overthink but think of it as a huge bathtub with things sloshing around (and remember that we haven’t been studying it all for very long either and are still figuring it out).

        • Thank you both. Yes, I understood that what he was speaking of was local and regional, but I guess my question was more related to whether he was focusing on the quasi-cyclic behavior associated with ENSO or the long-term trend associated with global warming as with the East Coast, or whether he may have been suggesting something more along the lines of how the trend may already be affecting ENSO, e.g., El Nino Modoki (as opposed to the more traditional El Ninos) becoming more common.

          And yes, there still are a fair number of questions in this area, whether at equilibrium La Nina-like conditions will tend to dominate, as suggested by the paleoclimate evidence, whether El Nino conditions may tend to dominate while the system is still warming, etc. I believe for the most part we have figured out in broad strokes how ENSO works, but both the Pacific Decadal Oscillation and Interdecadal Pacific Oscillation are a bit more mysterious, and yet both are closely tied to ENSO, particularly the PDO.

        • redskylite Says:

          I take the point about over thinking, Dr. Trenbeth did state that the sea level in the Western Pacific was 20cms higher than observed since 1992 by altimetry in satellites (and I read it is common for it to rise up to 30cms during an El-Nino) , but I am not sure if these satellite readings are adjusted for natural variations (such as El Nino). NASA would know but time is to short for me to worry about it.

          • dumboldguy Says:

            Not sure what you mean by “adjusted”. Readings are just readings—raw data. They are mathematically turned into averages and trends, which are analyzed.

  4. adelady Says:

    Timothy, this talk by Jerry Mitrovica is a bit of an eye-opener on sea level rise.

    He doesn’t really talk directly about the heat driven expansion of oceans, it’s more or less taken for granted. But he does explain a lot of the ice melt and gravity driven changes in local effects of rising, or falling, sea levels.

    • redskylite Says:

      Thanks for sharing that interesting and informative talk

    • adelady, a lot of interesting details there, whether it is how Greenland melt is actually reducing the rate at which sea levels rise in Europe, how Newton and crust rebound will to some extent actually help to stabilize places like West Antarctica, or how, once you take into account the specifics, what few tidal gauges we had good data from actually suggest a greater long-term sea level rise, with the mean actually being above our 95% level from only a few years ago. Well worth watching.

      Thank you! Actually I knew about the rebound and remember hearing about the rotation. The bit involving Newton surprised me though. Particularly some of the numbers he cited in relation to this. Either God or the Devil is in the detail, it would seem. I am not sure which, but no doubt we will work that out later.

  5. redskylite Says:

    I found this interesting climate science news article from December 2013:

    “There is also a very strong relationship with winds and sea level, according to Trenberth. Water is piling up in the western Pacific Ocean at a rate of around 10mm per year which is three times the global average. This has led to a difference in sea level, measured by satellite radars, between the western and eastern Pacific. “The sea level is 20cm higher in the western Pacific and the only way to keep it there is for strong winds to pile up the water. It is these changes in the winds that change the ocean currents and affect where the heat is going,” he explained. “But this can’t keep going for ever. The ocean wants to slop back to the east.”

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