Andrew Dessler on Satellite Errors
January 20, 2016
Twitter has certainly been a joy over the last few days, as climate deniers have gone off like Orville Reddenbacher’s premium popcorn over my most recent video, showing that the satellite temperature record has, well…problems.
It’s a big deal for deniers, because, the big pushback they were preparing for today’s announcement – 2015 is the hottest year in the record by far – was going to be “but the satellites”. The video has been making the rounds of thought leaders from the media, to capitol hill, to the Pentagon, and pretty much killed off that prospect.
Not that every record doesn’t need some adjustments – that’s normal for any data set. But when climate deniers like Ted Cruz, seek to take one small slice of one rather shakey data set (among tens of thousands) and proclaim that it is the truth, the whole truth, and the only truth – well, they kind of reveal themselves.
Andy Dessler was one of 15 scientists I interviewed last month at the American Geophysical Union Fall meeting in San Francisco – and certainly one of the most animated. He was one of the stars of the video, and here’s his core take on satellites and temperatures.
But those who try to cast doubt on accepted science — most often non-scientists — prefer satellite data that goes back to 1979. And the data shows that 2015 was only the third-warmest year on record.
Politicians who reject mainstream climate science, such as Republican presidential candidate Ted Cruz, especially cite one satellite measurement system, Remote Sensing Systems, in asserting that there has been no global warming for 18 years. That’s a claim scientists, including the one who runs RSS, say is misleading.
Carl Mears, senior scientist for Remote Sensing Systems, told The Associated Press in an email: “The satellite measurements do not measure the surface warming. They are measurements of the average temperature of thick layers of the atmosphere” about 50,000 feet off the ground.
“For impacts on human society and the environment, the surface data are more important,” Mears said.
Mears said his analysis of his own satellite data has five times the margin of error of ground measurements. That’s because satellites use complex mathematical algorithms and thousands of bits of code to translate wavelength measurements into temperature readings, Hayhoe said.
Scientists routinely use ground measurements to calibrate and validate satellite information, said Marshall Shepherd, a University of Georgia meteorology professor. He and several other scientists called surface measurements “the ground truth.”