Source: IPCC
URL: https://www.youtube.com/watch?v=bZONwnqWFe8
Date: 31/03/2014
Event: Michel Jarraud: "There is. No. Pause."
Attribution: IPCC
People:
[IPCC AR5 Working Group II Report Press Conference, Yokohama, Japan, 31 March 2014 (English).]
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Jonathan Lynn: Thank you. The webcast is going to end in just over five minutes, so we've got time for one, maybe two questions. Any... John Parker, at the back there, please.
John Parker: I just wondered how you dealt with the issue of the pause, the so-called temperature pause. I mean, did you say - um, you know, that - well, that climate impacts might not be so great, because we've seen, you know, a much smaller rise in temperatures in the past 15 years? Or did you say, well, by 2050 the pause might be over? I mean, how did you - how did you address that? How did you think about the issue of the pause?
Chris Field: Well, I think that the first thing that's important to recognise is that, from the earth system perspective, we haven't seen anything like a pause. What we've seen is that the earth has continued to warm at a rapid rate, that over the last few years - for reasons that are only partially understood - more of that warming has been showing up in the ocean and less - a lower fraction - has been showing up in the atmosphere. And even though the atmosphere has continued to warm, we've had more of the global warming showing up in the ocean. So the idea of a pause is not - it's just not correct, it's not - it's not what we're seeing in the data. What we're seeing in the data is continued rapid warming.
And this idea of a range of possible futures is really fundamental to the risk-framing approach that we've taken, in Working Group II. We have never, in the IPCC, said that we can predict with 100% certainty what the temperature's going to be in 2050 - there's always been a range. When we look at impacts, there's an even broader range, because we're looking at the dynamic interaction between rapidly changing human systems and rapidly changing natural systems. And so the way we think about the interaction between variability in the climate system - which is reflected in this increase in the fraction of the heating that's going into the oceans - is that it's part of the information you need, in order to make smart decisions in the context of the framing for risk.
In the big picture, the uncertainty about the responses of the physical system are small, very small, relative to the uncertainty in what's going to happen in the human systems, with population growth, changes in the world economy, changes in where people live. And all those need to be fit together into this comprehensive picture of how to deal effectively with the future.
Jonathan Lynn: Thank you. Michel.
Michel Jarraud: Yeah, I would like to come back to this "pause", because I think it's very misleading. There is. No. Pause. Thirteen out of the fourteen warmest years ever recorded occurred since the beginning of this century. What we call now a cold year - the coldest year since year 2001, which is actually 2011 - the coldest year in this period is actually warmer than any year before 1998. So I have real difficulties to accept that we can talk about a pause.
The thing which was expressed by Chris Field - it's, it is certainly true that the rate of increase - not the pause, the rate of increase - is somewhat less than it was in the previous things, because indeed we have got a number of - a significant fraction of the additional heat which is stored in the ocean - by the way, it's more than 90%, which is stored in the ocean. Since '98 - '98 you have to keep in mind, that whenever people talk about the pause they always use '98 as a starting point. This is not science. This is selecting very specifically the starting point, which was the warmest, the strongest El Nino of the last century. This is not what scientists do. What W. A. Moore [could he mean A. W. Moore?] recommends is that when you look at trends, you have to look at longer periods, not to isolate the starting point and the end point, to draw the conclusion that - that you would like to see.
So '98 was warmer because it was the strongest El Nino of the last century, and during an El Nino we tend to have more heat transfer from the ocean into the atmosphere. Now it happens that since '98 there were no strong El Nino, there were a number of La Nina, which also contributed to that. There was a number of interactions between the ocean and the atmosphere which contributed to that. As Dr. Field said, there's a number of factors and this is part of the natural variability, which itself is superimposed on the trend.
So you have to look at the trend and the variability. And, of course, if you look at short periods, you can end up by drawing the wrong conclusions. So no, there is no pause, and the global earth system - including the atmosphere, the ocean and the land surface - continues to warm.
[TO BE CONTINUED.]