“Many of the alarmists on global warming, they’ve got a problem because the science doesn’t back them up. In particular, satellite data demonstrate for the last 17 years, there’s been zero warming.”
–Sen. Ted Cruz (R-Tex,), “Late Night with Seth Meyers” interview, March 17, 2015
–Sen. Ted Cruz (R-Tex,), “Late Night with Seth Meyers” interview, March 17, 2015
“The last 15 years, there has been no recorded warming. Contrary to all the theories that – that they are expounding, there should have been warming over the last 15 years. It hasn’t happened.”
–Cruz, CNN interview released Feb. 20, 2014
–Cruz, CNN interview released Feb. 20, 2014
Cruz has been taking some heat — pun intended — lately over his global warming comments. While the recent focus has been on his interview on “Late Night with Seth Meyers,” Cruz made similar comments in the past, as shown in the CNN interview in February 2014.
Our friends at PolitiFact and our colleagues at Energy & Environment andThe Fix have debunked Cruz’s “Late Night” comments. But readers of The Fact Checker also asked us to take a look, so we did. Cruz, as the first official presidential candidate, has received a lot of attention for his remarks. And global warming likely will be a topic of interest as the election season gears up.
Is Cruz correct that there has been “zero warming” or “no recorded warming” in the last 15 to 17 years?
The Facts
After initial criticism of his interview, Cruz seemed to back away a bit from his comment about “zero” and “no recorded” global warming. In a March 24, 2015, interview with Texas Tribune, Cruz changed the statement to “no significant warming”: “I’m a big believer that we should follow the science, and follow the evidence. If you look at global warming alarmists, they don’t like to look at the actual facts and the data. The satellite data demonstrate that there has been no significant warming whatsoever for 17 years.”
Cruz’s spokesman Phil Novack told The Fact Checker that Cruz is using data showing global warming trends have been flat since 1998. Novack pointed us to several sources.
First, the reference to satellite data comes from these two analyses of global temperatures. The tables show that temperature levels have not reached the peak warm level in 1998. This is usually the starting point for skeptics who argue there has been no global warming in recent years; that year was particularly warm, due to an El Niño weather pattern.
In response to criticisms that Cruz only looked at satellite data, Novack also sent us other tables using various data points. The global temperatures data set looks like this:
The bottom graph is the relevant one here. The red and blue lines are two versions of satellite data. The black line is the weather balloon data. The green line is the actual surface level data. From 1998 to 2012, the last year in that data set, the red satellite data found a decrease in temperatures, at -0.043 degrees centigrade per decade. The rest found modest growth, ranging from 0.061 degrees to 0.072 degrees centigrade per decade.
But Carl Mears, senior scientist at Remote Sensing Systems who created the data set underlying the red satellite line, said temperature trends depend on the year chosen as the starting point. If you go back to 1993, for example, then all four lines show an increase in temperatures.
“You can look at the data since 1980, and it’s pretty clear that there’s an ascending trend there. But if you look at any 15-year period, it’s a lot less clear that the trend line that you drive might actually mean something,” Mears said.
Novack also sent us this graphic, which appears to show that temperatures have gone up since the late 1990s, though not significantly after 2000.
Researchers largely have agreed that the rate of global warming has slowed in recent years. The Intergovernmental Panel on Climate Changehas acknowledged that the rate of warming since the 1998 El Niño has been smaller than the rate calculated since 1951.
Global warming skeptics have latched on to this finding to assert there is no scientific evidence to show that global warming is still a concern. Yet the IPCC and other researchers have found that this trend is reflective of short-term natural variability, and that global warming is still a long-term concern.
There are many ways to measure global temperature. This study by Berkeley Earth, an independent nonprofit that studies land temperature data for climate science, looked at the various measures to understand this “pause” in global warming. Land/ocean temperatures (which is land temperature stations with sea surface data from ships and buoys) showed flat temperatures since 2001, though a long-term increase since 1970. Looking only at land temperatures, there was an increase since 2001. Ocean temperatures cooled slightly, and other measures still showed some increase in temperatures since 2001.
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