Washington Post Headline: “Worlds fish have been moving to cooler waters for decades, study finds”

This is an addition to the post Fishy Temperature Proxy by Anthony Watts.

INTRODUCTION

A new paper about fish migration patterns from 1970 to 2006 is getting some attention by the press. My Figure 1 is Figure 2 from Cheung et al (2013). Click it to enlarge it.

Figure 1

As usual, global warming enthusiasts in the press overlook some basic issues—like the sea surface temperatures for the Indian and Pacific Oceans from pole to pole haven’t warmed in 19+ years, and the Atlantic data show little warming for more than a decade. Further, the tropical Indian and Pacific sea surface temperatures haven’t warmed since 1986. It’s therefore difficult to make claims like “more evidence of a rapidly warming planet”, but that doesn’t stop proponents of hypothetical human-induced global warming.

BACKGROUND

Anthony Watts presented the press release for the paper Cheung et al (2013) Signature of ocean warming in global fisheries catch in the WattsUpWithThat post Fishy Temperature Proxy. And ClimateDepot’s Marc Morano alerted me earlier in the day to Lenny Bernstein’s May 15th article in the Washington Post. See “Worlds fish have been moving to cooler waters for decades, study finds”. The first two paragraphs of Bernstein’s article read (my boldface):

Fish and other sea life have been moving toward Earth’s poles in search of cooler waters, part of a worldwide, decades-long migration documented for the first time by a study released Wednesday.

The research, published in the journal Nature, provides more evidence of a rapidly warming planet and has broad repercussions for fish harvests around the globe.

Rapidly warming planet? Maybe the author of the Washington Post article should check sea surface temperature data before making nonsensical comments.

The University of British Columbia press release for the Cheung et al (2013) paper is titled “Fish thermometer” reveals long-standing, global impact of climate change. The opening two paragraphs of the press release provide a good overview of the paper:

Climate change has been impacting global fisheries for the past four decades by driving species towards cooler, deeper waters, according to University of British Columbia scientists.

In a Nature study published this week, UBC researchers used temperature preferences of fish and other marine species as a sort of “thermometer” to assess effects of climate change on the worlds oceans between 1970 and 2006.

I found no explanation in the paper about why they ended the study period in 2006 for a paper published in 2013 or, phrased another way, why they overlooked the most recent 6 years of sea surface temperature data. That aside…

WHAT THE PRESS RELEASE AND THE WASHINGTON POST AREN’T BOTHERING TO TELL THE PUBLIC

As noted in the introduction, the sea surface temperature anomalies of the Indian and Pacific Oceans from pole to pole (90S-90N, 20E-70W) haven’t warmed in 19 years. See Figure 2. The sea surface temperature anomalies for this major portion of the global oceans obviously warmed during the study period, 1970 to 2006, but they show no warming if the data is extended to current times and if we start the trend analysis in January 1994. In other words, the sea surface temperature data for about 70% of the surface of the global oceans provide no indication of warming for almost 2 decades.

Figure 2

That leaves us with the Atlantic data. It also shows warming from 1970 through 2006, but if we examine the data from January 2002 to January 2013, the trend has been remarkably flat—which suggests a possible slowdown in the warming rate of the sea surface temperatures in the Atlantic, too. It’s a little early to tell there, though, because there have been similar decadal slowdowns in the rate of warming in the Atlantic since 1970. It’s only a matter of time there, though. Eventually, the Atlantic Multidecadal Oscillation will cause the sea surface temperatures in the North Atlantic to peak, flatten and then start to cool—as it has for hundreds if not thousands of years. See NOAA’s FAQ webpage about the AMO.

Figure 3

The press release provides a link to a Pew Charitable Trusts – Environmental Initiatives overview of Cheung et al (2013). There they state (my boldface):

The authors found that, except in the tropics, catch composition in most ecosystems slowly changed to include more warm-water species and fewer cool-water species. In the tropics, the catch followed a similar pattern from 1970 to 1980 and then stabilized, likely because there are no species with high enough temperature preferences to replace those that declined. Statistical models showed that the increase in warm-water species was significantly related to increasing ocean temperatures.

What they forgot to tell you was that the sea surface temperatures of the tropical Indian and Pacific Oceans (24S-24N, 35E-80W) warmed drastically in response to the 1976 Pacific Climate Shift, see Figure 4, and then have remained relatively flat since then. In fact, the sea surface temperatures of the tropical Indian and Pacific Oceans show no warming since 1986, or for more than 2 ½ decades.

Figure 4

So where’s the “rapidly warming planet”?

CHEUNG ET AL (2013) DIDN’T SPECIFICALLY IDENTIFY THE HADISST SEA SURFACE TEMPERATURE DATA

Usually, peer-reviewed papers identify what datasets were used in the study. This courtesy appears to have been overlooked in Cheung et al (2013). Figure 2 in Cheung et al (2013) suggests a sea surface temperature dataset that has been infilled, because the trend analysis maps in their Figure 2 show data in the high latitudes of the Southern Hemisphere. And they also refer to the Hadley Centre’s sea surface temperature climatology in the paper. But for sea surface temperatures, Cheung et al (2013) don’t cite the expected Rayner et al (2003) for HADISST. They cite Belkin (2009) Rapid warming of large marine ecosystems, which cites Rayner et al (2003).

CLOSING

The Cheung et al (2013) paper hasn’t yet received the normal end-of-the-world-as-we-know-it hype from the alarmist blogs Climate Progress and SkepticalScience. It’s still a little early, though. Give Climate Progress and SkepticalScience a little while before they join the Washington Post, where Lenny Bernstein elected to make the claim of a “rapidly warming planet”. As so often happens, claims about warming sea surface temperatures are not supported by sea surface temperature data.

And of course, ocean heat content and satellite-era sea surface temperature data indicate the oceans warmed naturally. If this topic is new to you, refer to the illustrated essay “The Manmade Global Warming Challenge” [42MB].