How reliable is NASA’s pronouncement of 2014 as the warmest year on record?

The Federalist throws ice water on global warming alarmism. (H/T Blake)

Excerpt:

If 2014 is supposed to be “hotter” than previous years, it’s important to ask: by how much?

You can spend a long time searching through press reports to get an actual number on this—which is a scandal unto itself. Just saying one year was “hotter” or “the hottest” is a vague qualitative description. It isn’t science. Science runs on numbers. You haven’t said anything that is scientifically meaningful until you state how much warmer this year was compared to previous years—and until you give the margin of error of that measurement.

The original NASA press release did not give those figures—and most press reports just ran with it anyway. This in itself says a lot. When it comes to global warming, “journalism” has come to mean: “copying press releases from government agencies.”

But a few folks decided to do some actual journalism, and Britain’s Daily Mail reports that

the NASA press release failed to mention…that the alleged ‘record’ amounted to an increase over 2010, the previous ‘warmest year’, of just two-hundredths of a degree—or 0.02C. The margin of error is said by scientists to be approximately 0.1C—several times as much.

Pause for a moment to digest that. The margin of error was plus or minus one tenth of a degree. The difference supposedly being measured here is two hundredths of a degree—five times smaller than the margin of error. The Daily Mail continues:

As a result, GISS’s director Gavin Schmidt has now admitted NASA thinks the likelihood that 2014 was the warmest year since 1880 is just 38 per cent. However, when asked by this newspaper whether he regretted that the news release did not mention this, he did not respond.

This is not exactly a high point in the employment of the scientific method.

If we take into account this margin of error, the most we can say is that 2014 was, so far as we know, just as warm as 2005 and 2010. There is no significant difference between these years. And that gives the lie to claims of runaway global warming.

I got curious about whether Judith Curry had written anything recent about this story, and she has.

She writes:

Berkeley Earth has published a nice analysis of their 2014 data [link].  Summary of their main findings:

1. The global surface temperature average for 2014 was nominally the warmest since the global instrumental record began in 1850; however, within the margin of’error, it’s tied with 2005 and 2010 and so we can’t be certain it set a new record.

2. For the land, 2014 was nominally the 4th warmest year since 1753

3. For the sea, 2014 was the warmest year on record since 1850

4. For the contiguous United States, 2014 ranked nominally as the 38th warmest year on record since 1850.

Some other statements of interest:

Several European countries  set all time records for high annual average temperature, as did the continent of Europe as a whole

The margin of uncertainty we achieved was remarkably small (0.05C with 95% confidence).This was achieved, in part, by the inclusion of data from over 30,000 temperature stations, and by the use of optimized statistical methods. Even so, the highest year could not be distinguished. That is, of course, an indication that the Earth’s average temperature for the last decade has changed very little. 

Meanwhile, the ‘warmest year’ is noticeably missing in the satellite data sets of lower atmospheric temperatures.  Roy Spencer reports that 2014 was third warmest year since 1979, but just barely.

Interesting that temperature sensors in European countries reported higher temperatures.

Dr. Curry is Professor and former Chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. She has previously testified to Congress as an expert on climate change.

Roy Spencer does not think that land-based measurements of temperature are as reliable as satellite-based measurements. Do the satellite-based measurements confirm what NASA said?

He writes:

Most thermometers measure temperature where people live, and people tend to build stuff that warms the local environment around the thermometer.

Called the urban heat island (UHI) effect, most of the warming occurs long before the thermometer site actually becomes “urban”. For instance, if you compare neighboring thermometers around the world, and also compare their population densities (as a rough indication of UHI influence), it can be easily demonstrated that substantial average UHI warming occurs even at low population densities, about ~1 deg. F at only 10 persons per sq. km!

This effect, which has been studied and published for many decades, has not been adequately addressed in the global temperature datasets, partly because there is no good way to apply it to individual thermometer sites.

[…]For a “record” temperature to be statistically significant, it has to rise above its level of measurement error, of which there are many for thermometers: relating to changes in location, instrumentation, measurement times of day, inadequate coverage of the Earth, etc. Oh…and that pesky urban heat island effect.

A couple hundredths of a degree warmer than a previous year (which 2014 will likely be) should be considered a “tie”, not a record.

[…]Our satellite estimates of global temperature, which have much more complete geographic coverage than thermometers, reveal that 2014 won’t be even close to a record warm year.

In fact, the satellite and thermometer technologies seem to be diverging in what they are telling us in recent years, with the thermometers continuing to warm, and the satellite temperatures essentially flat-lining.

Here’s the graph:

UAH Global Temperature up to 2014
UAH Global Temperature up to 2014, as measured by satellites

It records the temperatures from satellites, which cannot be tampered with as easily as temperature sensors that are placed in urban areas. What we have here is a plateau, and not the hockey stick that was predicted by the global warming alarmists.

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