Alan Reynolds, Senior Fellow, Cato Institute

DeSmogBlog contributor Farron Cousins writes, “Newsweek Gives Cato Institute Climate Denier A Platform.” That means my piece, “Hurricanes Harvey and Irma Can’t Be Blamed on Global Warming.” But how could I possibly be a “Climate Denier” when I openly accepted NASA’s estimate that “Globally-averaged temperatures in 2016 were 1.78 degrees Fahrenheit . . . warmer than the mid-20th century mean.”

The points I raised are about (1) hurricanes and floods depending on local weather not global climate, and about (2) the 1998-2013 hiatus in ocean temperatures, and about (3) “global temperatures in 2016 [being] majorly influenced by strong El Niño conditions,” to quote NOAA. None of that has anything to do with “denying” that mean global temperatures are higher than they once were. It just questions supposed connections to recent hurricanes.

After taking Climate Change into account, NASA’s estimate of average annual global temperatures is 56-58 degrees Fahrenheit (since it includes winters and polar regions). But a 1 or 2 degree rise in global temperatures around 57.3 degrees seem a doubtful explanation for August’s Gulf of Mexico water temperatures closer to 87 degrees (even though the overall national temperature in August was just 72.0°F).

Once a hurricane is in motion, moving across warm water can help it pick up speed – which doesn’t cause the hurricane but could make it more intense. Roy Jensen finds no historical connection between major hurricane landfalls and Gulf temperature. And the NAOO

In fact, the U.S. had more Category 3, 4 and 5 hurricanes from the 1900s to the 1960s than there were since 1970.

Flooding is a different issue, since heavy rain (unlike storm surge) doesn’t require hurricane winds. Flooding from Hurricane Harvey might have been “a few inches” lower if the Gulf water had been two degrees cooler, as Washington Post writer Jason Samenow estimated. But a few inches are too few to matter.

Cousins includes Sea Surface Temperature (SST), not just surface warming. But the graph he uses from the EPA is only about very long-term global anomalies from 1880 to 2015 –far removed from the actual time and place of recent hurricanes.

The issue is not about whether the Gulf of Mexico in August 2017 was a degree or two warmer than usual (it was), but whether or not that local and seasonal “anomaly” can be plausibly be attributed any long-term warming trend in the yearly averages of global ocean or surface temperatures.

“Like many deniers,” writes Mr. Cousins, [Reynolds] attempts to link the warming waters in the Gulf of Mexico to everything except climate change, including El Nino. While other weather factors do contribute to temperature variations, he ignores the fact that overall temperatures in both the Gulf and the Atlantic Ocean are rising at a steady rate” [time period unspecified].

If Cousins hopes to blame a recent spike in Gulf temperatures on global warming, he can’t change the subject by making cryptic claims about temperatures in just one ocean out of five. The Atlantic doesn’t cover the globe.

I wrote about all oceans, not one, and reported a long hiatus when temperatures did not rise. I cited a 2017 survey of four data sources for ocean temperatures which found that “within 1998–2012. . . the upper 100-m experienced a weak warming (IAP and Ishii) or cooling (EN4-GR10), coincident with the global surface temperature slowdown discussed in recent literature (Xie).”

The prolonged 1998-2013 period of stable or cooling ocean temperatures ended when the world’s oceans and surface were warmed by a weak El Niño in 2014 and very strong one in 2015-2016 pulled unusually warm water up from equatorial Latin America through the Tropical North Atlantic – which includes the Gulf of Mexico. El Niño peaked at 4.3 °F at the end of 2015, persisted through May 2016, and left behind a lot of warm water in 2017.

A study this April, “The extreme El Niño of 2015–2016 and the end of global warming hiatus” by Yale Geophysicists Shineng Hu and Alexey V. Fedorov says, “Our results confirm that weak El Niño activity. . . was the cause of the hiatus, while the rapid [recent] temperature rise is due to atmospheric heat release during 2014–2016 El Niño conditions…” Shang-Ping Xie at Scripps came to similar conclusions in, “What Caused the Global Surface Warming Hiatus of 1998-2013.”

To “contradict” such points (when I made them), Cousins reprints an EPA graph of SST anomalies from 1880 to 2015 which uses one of the four data series I discussed. Too many years strain credulity and eyesight, making it difficult to see what the IPCC called a “global warming hiatus” between 1998 and 2013 (though another hiatus from 1937 to 1976 is visible).

The NOAA graph focuses on year-to-date anomalies from 1998 to 2017, for January to August. The baseline of 1901-2000 is much older and cooler than the EPA baseline of 1971-2000, making deviations appear larger.

Scholars from Yale and Scripps, among others, blame post-2013 warming on El Niño. But Cousins is an El Niño denier. He cites another denier Dana Nuccitelli who says, “The argument is easily debunked. While there was a strong El Niño event in 2015–2016, there was an equally strong event in 1997–1998. . . But according to Nasa, 2016 will be about 0.35°C hotter than 1998.” But drawing a line between two extreme years does not constitute a trend.

To indicate “steadily rising” temperatures the EPA/NOAA anomalies would have to have been steadily rising from 1998 to 2013. But they weren’t. The anomalies peak during El Niños in 1997-1998 and 2014-2016, but otherwise fluctuate up and down around the 1998 level. Warm (relative to 1901-2000), but not warming.

Nuccitelli advises sticking to “global temperatures on the surface where we live, and where temperatures are easiest to measure accurately.” But strained exertions to blame Hurricanes and floods on global warming depend entirely on water temperatures at the time and place of the hurricanes.

Another graph shows Gulf anomalies in red over the past two years. The anomalies were fairly high in August, but significantly higher earlier this year and twice in 2015-16.

Gulf of Mexico Anomalies

To reiterate, my previous blog/article argues that (1) annual ocean temps were not steadily rising from 1998 to 2013; that (2) volatile summer temperatures in the Gulf of Mexico have no apparent connection to annual averages of global temperatures; and that (3) El Niño is a likely suspect for much of the post-2013 warming of both global and Gulf waters.