The Guardian has a new blog called Climate Consensus – The 97%. The two primary authors are to be Dana Nuccitelli, a regular contributor at SkepticalScience, and John Abraham, Associate Professor at the University of St. Thomas.
Dana Nuccitelli’s first post at his new blog at The Guardian is titled “Why is Reuters puzzled by global warming’s acceleration?” His article is subtitled, “‘Climate scientists struggle to explain warming slowdown,’ said Reuters. But warming is speeding up, and scientists can explain it.” Nuccitelli’s first post at The Guardian is reminiscent of his posts at SkepticalScience—that is, it’s misleading and full of misinformation.
Data contradict the points Dana Nuccitelli is trying to make. In this post, we’ll briefly discuss ocean heat content data, how Mother Nature—not manmade greenhouse gases—creates warm water during La Niña events, how she releases that naturally created warm water during El Niño events and redistributes it around the oceans afterwards, and we’ll discuss Dana Nuccitelli’s misleading animation called “The Escalator”. Data explains how and why the vast majority of global warming occurred naturally…when it warmed.
OCEAN HEAT CONTENT
Nuccitelli begins his post with a picture from space of the Pacific Ocean with the caption:
Oceans, such as the Pacific pictured here from space, are absorbing much of the warming the planet is currently experiencing. NASA/ Roger Ressmeyer/ Corbis
Then the first sentence of his post reads:
The rate of heat building up on Earth over the past decade is equivalent to detonating about 4 Hiroshima atomic bombs per second.
Based on Nuccitelli’s opening illustration and statement, we should expect the ocean heat content of the Pacific Ocean to be showing a monumental amount of warming over the past 10 years. But, as shown in Figure 1, the ocean heat content data for the Pacific Ocean from pole to pole (90S-90N, 120E-80W) shows cooling. Right from the get go, data disagrees with Nuccitelli’s representations.
The NODC’s Ocean Heat Content data used in Figure 1 (and in the other ocean heat content graphs in this post) is the only regularly updated dataset of its kind that’s available to the public on a gridded basis through the KNMI Climate Explorer. There, users can select the coordinates of the data they desire. The NODC’s ocean heat content data represents the change in the heat stored in the oceans to depths of 700 meters or about 2300 feet.
The article in The Guardian also fails to describe all of the problems associated with ocean heat content data. Before the ARGO floats were deployed starting in the early 2000s, the temperature observations at depth were so sparse that the data has to be taken with more than a grain of salt, especially when dealing with the data below 700 meters. And the ARGO-era ocean heat content data has been adjusted so many times it’s difficult to keep track of all of them. Many of the problems with ocean heat content data were described in the blog post Is Ocean Heat Content Data All It’s Stacked Up to Be? It’s a long post, I’ll grant you that, but if you’re interested in ocean heat content data, it’s worth a read. Bottom line: even with all of the adjustments to the ARGO-era that added warming to the ocean heat content data, the Pacific data shows cooling over the past 10 years—contrary to what Dana Nuccitelli implied with his opening statement and illustration.
HOW LA NIÑAS CREATE WARM WATER IN THE TROPICAL PACIFIC
We often hear from the media that the (surface air) warming has slowed or paused over the past 15 years. This isn’t a puzzle; climate scientists are well aware of several contributing factors, as a recent Reuters article – “Climate scientists struggle to explain warming slowdown” – eventually discussed. The accelerated warming of the oceans is likely the main contributor.
During years with La Niña events, more heat is transferred to the oceans, and surface temperatures are relatively cool as a result. The opposite is true during El Niño years. During the 1990s, there were more El Niño than La Niña events, which resulted in more surface air warming. One of the strongest El Niño events of the century happened in 1998, which not coincidentally was 15 years ago.
Dana fails to explain that Mother Nature, not greenhouse gases, creates ocean heat in the tropical Pacific–where El Niño and La Niña events take place. During La Niña events, the trade winds in the tropical Pacific are stronger. The stronger trade winds reduce cloud cover, which, in turn, allows more sunlight (also known as penetrating solar radiation because it penetrates into the oceans) to warm it. That’s why the long-term warming of the ocean heat content for the tropical Pacific was plainly caused by the 3-year La Niña events of 1954-57, 1973-76 and 1998-01, and during the freakish 1995/96 La Niña. Keep in mind that the 1995/96 La Nina provided the fuel for the 1997/98 El Niño, which was discussed by Nuccitelli. See Figure 2.
To further illustrate the role of La Niñas in the warming of the tropical Pacific, Figure 3, the ocean heat content there would have cooled since the 1950s without the 1973-76 and 1995/96 La Niña events.
Back to Nuccitelli’s statement:
During years with La Niña events, more heat is transferred to the oceans, and surface temperatures are relatively cool as a result. The opposite is true during El Niño years. During the 1990s, there were more El Niño than La Niña events, which resulted in more surface air warming.
That discussion is also misleading for other reasons. Sea surface temperatures (not ocean heat content) in the tropical Pacific cool in response to La Niña events because more cool waters than normal are being upwelled from below the surface of the eastern equatorial Pacific. Marine air temperatures and lower troposphere temperatures cool in response because the tropical Pacific is releasing less heat than normal through evaporation as a result of the cooler surface waters. (That cooler upwelled water is then warmed by the La Niña-caused additional sunlight as it travels from east to west across the tropical Pacific, and it collects in an area east of Indonesia called the west Pacific Warm Pool, where it warms the ocean heat content of the tropical Pacific.)
Note: The sea surface temperature data presented in this post is NOAA’s best: the Optimum Interpolation Sea Surface Temperature data, version 2, also known as Reynolds OI.v2. It’s a combination of observations from satellites, buoys and ship inlets. As noted in the link:
The optimum interpolation (OI) sea surface temperature (SST) analysis is produced weekly on a one-degree grid. The analysis uses in situ and satellite SST’s plus SST’s simulated by sea-ice cover. Before the analysis is computed, the satellite data is adjusted for biases using the method of Reynolds (1988) and Reynolds and Marsico (1993).
EL NIÑO EVENTS
An El Niño event releases that La Niña-created warm water from below the surface of the west Pacific Warm Pool, and an El Niño spreads that warm water eastward across the eastern tropical Pacific. There was so much warm water released by the 1997/98 El Niño that the sea surface temperatures for the entire East Pacific Ocean (from pole to pole or the coordinates of 90S-90N, 180-80W) temporarily warmed 0.5 to 0.6 deg C. See Figure 4. The East Pacific Ocean with those coordinates represents about 33% of the surface of the global oceans, so that was a monumental amount of naturally created warm water that was released by the 1997/98 El Niño. Notice also that the East Pacific sea surface temperature data hasn’t warmed over the 31 years of that dataset, based on the linear trend.
All of that naturally created warm water that’s now on the surface doesn’t simply disappear after a strong El Niño. Ocean currents redistribute that leftover warm water to adjoining ocean basins (which prevents the sea surface temperatures for remote areas, like the North Atlantic, from cooling proportionally during the trailing La Niña). The leftover warm water (and its counteracting effects on the trailing La Niña) is why the sea surface temperatures for the Atlantic, Indian and West Pacific Oceans warmed in a very obvious upward step of about 0.19 deg C, Figure 5, in response to the 1997/98 El Niño. Note that there was also a strong upward shift in response to the 1986/87/88 El Niño and a smaller step in response to the 2009/10 El Niño.
Without those El Niño events, the sea surface temperatures for the Atlantic, Indian and West Pacific Oceans would not have warmed since the early 1980s.
Nuccitelli was right with his statement, “During the 1990s, there were more El Niño than La Niña events, which resulted in more surface air warming.” But he failed to advise his readers:
1. that land surface air temperatures represent only 30% of the global surface temperature record,
2. that sea surface temperature data represent the other 70%,
3. that the satellite-era sea surface temperature data indicate sea surface temperatures warmed naturally in response to the naturally created warm water released from below the surface of the tropical Pacific during strong El Niños, and
4. that the warming of land surface air temperatures is primarily a response to the warming of sea surface temperatures.
For more information, including a discussion of the natural warming of ocean heat content data, refer to my illustrated essay “The Manmade Global Warming Challenge” [42MB]. For even more information, there’s more detail in my ebook Who Turned on the Heat? which was introduced in the blog post here. It’s available in pdf form here for US$8.00.
Nuccitelli goes on to write:
Reuters didn’t connect the dots between these two articles, telling us one week that oceans help explain the surface warming slowdown, and the next week claiming the slowdown is puzzling climate scientists. However, these ‘slowdowns’ happen on a regular basis. You can find one every 5 to 10 years in the surface temperature data, as illustrated in a graphic I created nicknamed ‘The Escalator‘.
The escalator is included here as Animation 1.
The caption for “The Escalator” reads:
Average of NASA GISS, NOAA NCDC, and HadCRUT4 monthly global surface temperature anomalies from January 1970 through November 2012 (green) with linear trends applied to the timeframes Jan ’70 – Oct ’77, Apr ’77 – Dec ’86, Sep ’87 – Nov ’96, Jun ’97 – Dec ’02, and Nov ’02 – Nov ’12.
Let’s drop back to what Nuccitelli wrote earlier:
One of the strongest El Niño events of the century happened in 1998, which not coincidentally was 15 years ago.
When people say ‘no warming in 15 years’, they’re cherry picking the timeframe to begin in an abnormally hot year.
“The Escalator” by definition is an exercise in cherry picking. Let’s illustrate, with the same data used by Nuccitelli, how global surface temperatures actually warmed without cherry picking the time periods. We’ll simply highlight 3 naturally occurring events, and use them as start and end years for shorter-term data illustrations.
Figure 6 shows the global land surface air temperature plus sea surface temperature anomalies (average of GISS LOTI, HADCRUT4 and NCDC datasets, like The Escalator) before, during and after the 1997/98 El Niño. The data highlighted in red are for the official El Niño months of the 1997/98 El Niño from NOAA’s Oceanic NINO Index. There was little warming during the years leading up to the 1997/98 El Niño and in the years following it. I’ve included period-average temperatures in blue to help highlight that fact. The dip in 1991 and rebound in 1994 is associated with the explosive volcanic eruption of Mount Pinatubo. That cooling is a response to the decrease in penetrating solar radiation caused by the “shading” effects of aerosols spewed into the stratosphere by the explosive volcano—not from a decrease in manmade greenhouse gases. That aside, the vast majority of the warming during the period of March 1988 to February 2013 was caused by the monumental amount of naturally created warm water released from below the surface of the tropical Pacific by the 1997/98 El Niño and redistributed on the sea surface after it–warm water that was created during the 1995/96 La Niña.
You’re probably wondering why I started the graph in Figure 6 at March 1988. That’s the first month after NOAA’s official months for the 1986/87/88 El Niño. If we look at the global surface temperature anomalies from March 1977 to April 1997 (the month before the 1997/98 El Niño), Figure 7, we can see that the 1986/87/88 El Niño caused a similar upward shift in global surface temperatures. The upward steps in Figures 6 and 7 are blatantly obvious when we break the data down into logical shorter time periods before and after the strong El Niño events. (Note: There was also a very strong El Niño in 1982/83, but the eruption of El Chichon in 1982 counteracted the impact on global surface temperatures of all of the warm water it released.)
Now for the period before the 1986/87/88 El Niño: See Figure 8. I’ve started the graph 10 years before The Escalator to show how “flat” global temperatures were leading up to the upward step in global temperatures in 1976. That step is associated with the Pacific Climate Shift, when the sea surface temperatures of the East Pacific ocean suddenly shifted upwards. There are numerous peer-reviewed papers that attempt to explain that natural warming, many with different causes and effects. That shift coincides with the end of the 1973-76 La Niña, which created, as shown Figure 2, the initial warm water used by the trailing El Niño events until the 1995/96 La Niña. Regardless of the cause, there was an obvious upward shift in global surface temperatures in 1976. I’ve highlighted in red the official months of the 1976/77 El Niño as a proxy for the climate shift. The upward step is pretty tough to miss. And again, I’ve used period average temperatures (in blue) before and after the 1976 climate shift to help illustrate its impact on global surface temperatures and to show how “flat” global temperatures were before and after that shift.
Now, if we merge all of the data from Figures 6 through 8, we have a more realistic view on how, when and why global surface temperatures warmed—a more realistic escalator. See Figure 9. There was no cherry picking involved, just a little common sense to highlight the primary causes of global warming since 1960.
Ocean heat content data for the Pacific Ocean contradicts Dana Nuccitelli’s opening statement and illustration. The ocean heat content data for the tropical Pacific show that Mother Nature is responsible for the fuel for El Niño events. Ocean Heat Content data and satellite-era sea surface temperature data also indicate the oceans warmed naturally, but you have to understand that ENSO works as a recharge-discharge oscillator (with La Niña as the recharge mode and El Niño as the discharge mode) to see Mother Nature’s handiwork. And as illustrated, Dana Nuccitelli’s Escalator is simply another way for global warming enthusiasts to hide how global temperatures actually warmed since 1976. In short, data contradicts Dana Nuccitelli’s first post at The Guardian’s new blog.
Feel free to furnish a link to this post at Dana Nuccitelli’s new home at The Guardian. The more the merrier. Unlike SkepticalScience, I don’t believe The Guardian has a track record of deleting comments that disagree with the hypothesis of human-induced global warming. And if Nuccitelli’s posts at The Guardian are similar to his posts at SkepticalScience, he’ll be presenting “The Escalator” again and again, so you can link this post to his future uses of The Escalator at The Guardian, too. And don’t forget the YouTube video On the SkepticalScience Video “Global Warming over the Last 16 Years” when he links that video from SkepticalScience.