UPDATE: I’ve corrected a few typos that carried over into two of the graphs and, at the end, I’ve added a model-data comparison of the sea surface temperature anomalies for the Indian and Pacific Ocean subset.
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A week after typhoon Haiyan stormed through the Philippines, the website EcoWatch ran an article by Michael Mann. The blog post was titled Super Typhoon Haiyan: Realities of a Warmed World and Need for Immediate Climate Action. Michael Mann began with a commendable request for Philippine Red Cross Donations. But after that, once again, we have an activist celebrity—one who masquerades as a climate scientist—using the misfortunes of others in efforts to advance a political agenda. And to make the effort even more futile on Mann’s part, much of the evidence he presented has no basis in reality.
For now, super storms are still rare. However, models suggest more frequent and intense storms in a warmed world. A number of scientists suspect that certain recent storms like Sandy and Haiyan exhibited characteristics outside the range of natural variation.
Unfortunately, deadly tropical cyclones (typhoons and hurricanes) have existed in the past and they will exist in the future. Steve Goddard has had numerous blog posts recently at RealScience about tropical cyclones, including a few with a link to the WeatherUnderground webpage that lists the 35 Deadliest Tropical Cyclones in History. Also, Paul Homewood of NotALotOf PeopleKnowThat plotted the number of tropical cyclones listed on the Wikipedia webpage here, with the same intensity as typhoon Haiyan (based on barometric pressure). See my Figure 1, which is from Paul’s post Most Intense Typhoons On The Decline.
The peer-reviewed paper linked by Mann was Emanuel (2013) Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century. It’s obviously a climate model-based study. Sea surface temperatures are one of the primary ingredients of the tropical cyclone recipe, and we’ve illustrated and discussed in numerous posts that climate models show no skill at being able to simulate sea surface temperatures, so there’s no reason to believe their prognostications. Additionally, using a table prepared by Australia’s BOM (Bureau of Meteorology), NOAA indicates on their Weather Impacts of ENSO webpage that the number of tropical cyclones in the northwest tropical Pacific is influenced by El Niño and La Niña events. But climate models cannot simulate the basic processes of El Niño or La Niña events (see Guilyardi et al (2009) and Bellenger et al (2013)), so the study by Kerry Emanuel has little to no merit. For those new to this discussion, let me once again quote a key sentence from Guilyardi et al (2009). Note: ENSO (El Niño-Southern Oscillation) in the following is a commonly used acronym for El Niño and La Niña:
Because ENSO is the dominant mode of climate variability at interannual time scales, the lack of consistency in the model predictions of the response of ENSO to global warming currently limits our confidence in using these predictions to address adaptive societal concerns, such as regional impacts or extremes (Joseph and Nigam 2006; Power et al. 2006).
Michael Mann may believe that “A number of scientists suspect that certain recent storms like Sandy and Haiyan exhibited characteristics outside the range of natural variation”, but the IPCC (the political body that helped make him an eco-celebrity) contradicts the “number of scientists”. The IPCC states very clearly on page 7 of 165 of Chapter 2 of their 5th Assessment Report (their boldface):
Confidence remains low for long-term (centennial) changes in tropical cyclone activity, after accounting for past changes in observing capabilities.
Additionally, the IPCC continues on page 62:
Current datasets indicate no significant observed trends in global tropical cyclone frequency over the past century and it remains uncertain whether any reported long-term increases in tropical cyclone frequency are robust, after accounting for past changes in observing capabilities (Knutson et al., 2010).
Moving on, Michael Mann writes:
Although exact measurements are hard to come by (there were no flights in the Western Pacific to provide direct measurements) satellite images along with readings of ocean heat seem to suggest that Haiyan was an unnaturally powerful storm. The science is hinting that this storm may not have been so catastrophic in a world without warming.
Unnaturally? Oy vey. Mann’s link in that paragraph is to a blog post by Greg Laden Why Was Typhoon Haiyan/Yolanda So Powerful, and is this a trend? In the following blog posts, we’ve addressed many of the points Greg Laden attempted to make:
- Typhoon Haiyan Sea Surface Temperature Anomalies for Early Storm Track
- Games People Play(WattsUpWithThat Cross Post)
- Are Greg Laden’s Reading Comprehension Skills at an All-Time Low?
- Tropical Cyclone Heat Potential – It’s All in the Presentation(WattsUpWithThat Cross Post)
Greg Laden included a graph here reported to be from Kerry Emanuel’s 2005 paper Increasing destructiveness of tropical cyclones over the past 30 years. I found that graph quite curious. If we look at sea surface temperature trend map of the Indian and Pacific Oceans from 1994 to 2012, Figure 2, we can see little warming in the northwest equatorial Pacific. Two decades is a reasonable amount of time. The sea surface temperature dataset, HADISST, is the same date presented in that paper. Emanuel’s graph included the much-smoothed sea surface temperature anomalies for the region bordered by the coordinates of 5N-15N, 130E-180. I’ve highlighted that region on the map. An ENSO-related spatial pattern (what some would call a Pacific Decadal Oscillation-related pattern) is visible in the map.
As shown, there is no warming illustrated in the region used by Kerry Emanuel in his 2005 paper for the period of 1994 to 2012, the last 19 years. Why start the data in 1994? If we extend the trend map into years earlier than 1994, then the trends are being influenced by the residual cooling effects of the aerosols spewed into the stratosphere by the 1991 eruption of Mount Pinatubo.
Figure 3 illustrates the sea surface temperature anomalies for that region in the northwest tropical Pacific for the period of January 1994 to August 2013. As shown, the warming rate is a minuscule 13 one-thousandths of a deg C per decade. Or better said, the sea surface temperatures show little to no warming in that region for the past 20 years.
Let’s extend the HADISST-based sea surface temperature data out to the entire region shown in Figure 2. That is, we’ll look at the sea surface temperature anomalies for the Indian and Pacific Oceans, from pole to pole, for the period of January 1994 to August 2013. The warming rate is even lower, at 6 one-thousandths of a deg C per decade.
It’s tough to claim, as Michael Mann did, that “The science is hinting that this storm may not have been so catastrophic in a world without warming,” when the data indicate the sea surface temperatures for the Indian or Pacific Oceans have not warmed in 2 decades. Maybe Michael Mann should check data before he makes claims that aren’t supported by data. That way he wouldn’t look so foolish when someone, like me, calls his bluff.
Note: Figure 4 uses the same coordinates and sea surface temperature dataset as the model-data comparison here, which was included in the post A Blog Memo to Kevin Trenberth – NCAR. According to the climate models used by the IPCC for their 4th Assessment Report, the sea surface temperatures of the Indian and Pacific Oceans should have warmed 0.31 deg C over that time period…if they were warmed by manmade greenhouse gases.
I would have liked to update that model-data comparison for this post, using the models prepared for the IPCC’s 5th Assessment Report. Unfortunately, there is a temporary glitch at the KNMI Climate Explorer, and the multi-model mean of the CMIP5 simulations of sea surface temperatures are presently not available. Rest assured, though, that there would not have been an improvement with the CMIP5 models. See the update at the end of the post.
Michael Mann continues on that tack with:
The unusually deep, unusually warm pool of water that provided the initial fuel is unlikely to have existed in a world without warming.
The not “unusually deep,” not “unusually warm pool of water” is a product of the trade winds that blow across the tropical Pacific. The warm water “piles up” against the land masses in the western tropical Pacific. As a result, warm water accumulates there to depths of about 300 meters. The region is known by a number of names, including the West Pacific Warm Pool and the Indo-Pacific Warm Pool. See Mehta and Mehta Natural decadal-multidecadal variability of the Indo-Pacific Warm Pool and its impacts on global climate. That warm water, created by sunlight, is occasionally released from below the surface of the western tropical Pacific by El Niño events. There is nothing unusual about the processes that drive El Niño and La Niña events.
Additionally, to counter Michael Mann’s claims of “unusually deep, unusually warm pool of water” we have the recent 2013 paleoclimatological paper Pacific Ocean Heat Content During the Past 10,000 Years by Rosenthal et al. It indicates that ocean heat in the Pacific was warmer in centuries past than it is today.
That paper made the rounds through the blogosphere. Michael Mann even commented on it in his post at EcoWatch titled Pacific Ocean Warming at Fastest Rate in 10,000 Years so he understands that there are reconstructions that counter his claims. Refer also to Steve McIntyre’s post here. To put things in perspective, Steve spliced NODC data onto the end of one of the graphs by Rosenthal et al (2013). See my Figure 5.
Steve’s caption reads:
Figure 1. Annotation of Rosenthal Figure 3B. Original caption: “Compiled IWT anomalies based on Indonesian records spanning the ~500- to 900-m water depth (for individual records, see fig. S7). The shaded band represents +-1 SD. Red- OHC Pacific 0-700m heat content converted to temperature using the 0-700m Pacific mass shown in the Rosenthal SI. The values are consistent with 0-700m temperature anomaly values at NOAA http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/index3.html.
In my annotation of their Figure 3B shown above, I’ve shown two trend lines, each of which more or less corresponds to the trends reported on lines 2 and 3 of Table S3: a trend of -0.15 deg C/century from 1100-1700 and a trend of 0.09 deg C/century from 1600-1950.
Steve also writes about that illustration:
On the far right, I’ve plotted Pacific ocean heat content, converted to deg C anomaly (red), together with its trend line. The two solid yellow lines show trend lines for 1100-1700 AD and 1600-1950 AD, two of the three periods considered in Rosenthal Table S4. It is true that the rate of change over the past 55 years is somewhat higher than the trend over 1600-1950, but it is not “15 times higher”. While I don’t think that one can safely reify the fluctuations in Rosenthal’s IWT reconstructions, on the other hand, these fluctuations appear to me to preclude any strong conclusions that the relatively modest increase is unprecedented.
But the best counter to the claims that the recent warming is the “fastest in 10,000 years” comes from one of the authors interviewed by Andy Revkin. See the NewYorkTimes blog here and the YouTube video here. Andy Revkin asks the authors if they could rule out whether there were rapid changes in the past. Co-author Brad Linsley replies in part at about the 4-minute mark.
You could say that we probably have century-scale resolution at best. It’s possible that the sediments just didn’t record similar warmings in the past.
Let’s put that in perspective. The NODC’s ocean heat content data for the depths of 0-700 meters and 0-2000 meters only extends back in time to 1955, or a little less than 60 years, but the resolution of the Rosenthal et al is “century scale”. Thus Brad Linsley’s statement, “It’s possible that the sediments just didn’t record similar warmings in the past.” There’s little chance they’d even notice a warming rate that was similar to the one presented by the NODC data for 60 years.
In his post Super Typhoon Haiyan: Realities of a Warmed World and Need for Immediate Climate Action, Mann gives a short spiel about global warming:
But herein lies the crux—we no longer live in a world without warming. Given that 1985 was the last year with temperatures below the 20th century average, and 2000-2010 was the hottest decade on record, it has become impossible to say for certain that any given storm is free from the influence of our warmed world.
We’ve illustrated and discussed in numerous blog posts for almost 5 years that ocean heat content data and satellite-era sea surface temperature records indicate the warming of the global oceans occurred via natural processes, not from increased emissions of manmade greenhouse gases. There’s no reason to repeat that discussion again here. If this subject is new to you, see the illustrated essay “The Manmade Global Warming Challenge” (42MB).
Mann goes on to talk about sea level rise:
While contrarians may dislike it when activists or actors like George Clooney point out the linkage between climate change and extreme weather, the bottom line is this: climate change makes tropical storms more damaging. Not only through increased wind speed and rainfall, but most notably through rising sea levels. This means greater damage and loss of property and life.
As I noted in my recent book Climate Models Fail:
Sea levels have climbed 100 to 120 meters (about 330 to 390 feet) since the end of the last ice age, and they were also 4 to 8 meters (13 to 26 feet) higher during the Eemian (the last interglacial period) than they are today. (Refer to the press release for the 2013 paper by Dahl-Jensen, et al. “Eemian Interglacial Reconstructed From a Greenland Folded Ice Core”.) Whether or not we curtail greenhouse gas emissions (assuming they significantly affect climate at all), if surface temperatures remain where they are (or even if they resume warming, or if surface temperatures were to cool a little in upcoming decades), sea levels will likely continue to rise. Refer to Roger Pielke, Jr.’s post “How Much Sea Level Rise Would be Avoided by Aggressive CO2 Reductions?” It’s very possible, before the end of the Holocene (the current interglacial), that sea levels could reach the heights seen during the Eemian. Some readers might believe it’s not a matter of if sea levels will reach that height; it’s a matter of when.
After quoting the delegate from the Philippines at this year’s United Nations Climate Talks in Poland, Michael Mann then calls for action:
Let that call echo, and be heard in response to those who would insist on waiting for the next storm to take action.
But, of course, Michael Man offers no course of action. If Michael Mann is suggesting that reductions in emissions of manmade greenhouse gases will stop cyclones like Haiyan from reoccurring and also end the rise in global sea levels, then–how can I put this nicely?–he’s delusional. If Michael Mann is suggesting the people of the Philippines create a typhoon warning system and an enforced plan that relocates residents from low-lying areas and that provides adequate shelter from the impacts of the storm, then, I believe, all would agree. Unfortunately, I believe Michael Mann has greenhouse gases in mind.
UPDATE: KNMI has fixed the bug in the Climate Explorer. (Thanks, Camiel.) Figure 6 is a model-data comparison of the sea surface temperature anomalies for the Indian and Pacific Ocean since 1994. The coordinates used are 90S-90N, 20E-80W. That region represents about 70% of the surface of the global oceans. The graph includes the multi-model ensemble mean of the CMIP5-archived models, which were used by the IPCC for their 5th Assessment Report. They simulated a virtual warming rate for that colossal region of 0.186 deg C/decade, or a total warming of more than 0.35 deg C since 1994. But the satellite-enhanced, HADISST-based sea surface temperatures of the real Indian and Pacific Oceans have shown little to no warming for almost 2 decades.
Maybe the climate scientists who believe manmade greenhouse gas-induced warming contribute to typhoons are looking at model outputs and not observations-based data.