Quick Comments on England et al. (2014)

England et al. (2014) paper Recent intensification of wind-driven circulation in the Pacific and the ongoing warming hiatus has been getting a lot of press around the blogosphere. The HockeySchtick has an excellent overview here,  Anthony Watts introduced the paper in his WattsUpWithThat post here, Jo Nova has a guest post by William Kininmonth here, and Dana Nuccitelli added the warmist spin on the paper for SkepticalScience here.  The following are a few quick comments about England et al. (2014).

The England et al. (2014) paper appears, in many respects, to be a continuation of Meehl et al. (2013), which we discussed here.  England et al (2014) are defining the multidecadal variability of El Niño and La Niña dominance with the abstract metric called the Interdecadal Pacific Oscillation.  See the post linked in this paragraph for more information about the Interdecadal Pacific Oscillation.  It seems odd that these papers use abstract forms of sea surface temperature data as proxies for multidecadal variations in ENSO.  The terms ENSO, El Niño and La Niña do not appear in the abstract of England et al. (2014).  Why?  The Interdecadal Pacific Oscillation is primarily an aftereffect of ENSO.

Much of England et al. (2014) was devoted to climate models and how the models did not properly simulate the recent stronger trade winds experienced in tropical Pacific—stronger trade winds that were due to the dominance of La Niñas.  When England et al. forced the models with trade wind data, which vary in response to El Niño and La Niña events, then the modeled rate of surface warming declined.  Obviously, the climate models used by the IPCC will have to be able to simulate basic ENSO processes if the models are to have any value at predicting future climate on multidecadal bases.

Phrased another way, England et al. (2014) admit that the climate models used by the IPCC for the 5^th Assessment report (the CMIP5 models) failed to capture one of the aspects that can cause surface temperatures to stop warming—a dominance of La Niña conditions. They’re obviously implying that a dominance of El Niño conditions (like we experience from 1976 to 1998) contributed to the warming.  They’re also implying that the projections of future climate by the CMIP5 models are basically worthless because the models cannot simulate the multidecadal variations in El Niño and La Niña dominance, which cause surface temperatures to warm (during periods of El Niño dominance) or to not warm (during periods of La Niña dominance).

Guilyardi et al. (2009) and Bellenger et al (2013) were very critical of how climate models simulated the processes of ENSO.  We’ve referenced those papers in numerous posts over the past year, most recently in Our Climate Models Are Aglow with Whirling, Transient Nodes of Thought Careening through a Cosmic Vapor of Invention.

We discussed ocean heat uptake in the recent Open Letter to Kevin Trenberth – NCAR. While the ocean heat content of the western tropical Pacific has increased since 1999, on the other hand, in the eastern tropical Pacific, ocean heat has decreased, resulting in a net decline in ocean heat content for the entire tropical Pacific in that time. In that same Trenberth post, we showed that the subsurface temperatures for the entire Pacific to depths of 2000 meters showed little warming, and that the warming to depth was occurring in the South Atlantic and Indian Oceans only.  This appears to contradict the model-based findings of England et al. (2014).

One last comment:  England et al. (2014) claim recent trade wind strengths are “unprecedented”:

Here we show that a pronounced strengthening in Pacific trade winds over the past two decades—unprecedented in observations/reanalysis data and not captured by climate models…

England et al. (2014) show the outputs of reanalyses of wind stress anomalies in the bottom cell of their Figure 1.  The wind stress anomalies are for the region bordered by the coordinates of 6S-6N, 180-150W.  As you’ll recall, a reanalysis is the output of a computer model. It is not data.  Data are used as inputs to reanalysis.

England et al Figure 1

Unfortunately, there is little source wind data for the eastern equatorial prior to the 1960s. Thus the need for England et al. to rely on reanalyses. 

The caption for the lower cell reads (my boldface):

Pacific wind stress anomalies are computed over the region 6° N–6° S and 180°–150° W (green rectangle in Fig. 2a), corresponding to where the IPO exhibits maximum regression onto Pacific Ocean winds. Anomalies are shown relative to the historical record for two climatologies (Methods), with a bold line indicating the strength of the 20-year trends leading up to each year shown. In both reanalysis products shown, the recent multidecade acceleration in Pacific trade winds is the highest on record, although estimates of observed winds are not well constrained by measurements previous to the satellite era…

The satellite era started the late 1970s, so before then, there is poor sampling of wind stress anomalies. ICOADS is the source of wind data for the oceans. Animation 1 presents maps of the “u” (east-west) zonal component for the Januaries 1910, 1920…through 2010, based on the ICOADS database. As shown, there is little wind data for the equatorial Pacific prior to the 1960s. You can see the ship tracks in the early maps, so the data are based only on readings taken as the ships sailed across the region, sometime during the month.

Animation 1

How would England et al (2014) know if recent trade wind strength was “unprecedented” when there is little real data to support such a claim?

CLOSING

In a number of past posts, we’ve illustrated and discussed how poorly climate models simulate sea surface temperatures.  Two recent examples:

• IPCC Still Delusional about Carbon Dioxide
• CMIP5 Model-Data Comparison: Satellite-Era Sea Surface Temperature Anomalies

Global surface temperatures are dependent on the annual, multiyear, decadal and multidecadal variations in sea surface temperatures. And sea surface temperatures, of course, depend on coupled ocean-atmosphere processes that cannot be simulated by climate models. If and when the climate models used by the IPCC are able to properly simulate the multidecadal variations in those couple ocean-atmosphere processes, the climate models may be useful in projecting future climate; until that time, climate models are not fit for purpose…plain and simple.