Researchers have improved the uncertain temperature measurements conducted by NASA’s Goddard Institute for Space Studies (GISS) to incredible precision. As reported in Journal of Geophysical Research-Atmospheres, the GISS Surface Temperature (GISTEMP) measurements’ uncertainty has shrunk to just 0.05°C (0.09°F) for data collected in recent decades and to 0.15°C (0.27°F) for measurements taken 140 years ago, when the records began.
The analysis, once again, shows the increase in global temperatures from 1880 to today of about 1.1°C (2°F). It also reestablished 2016 as the hottest year on record, followed by 2017, 2015, and 2018. The 10 hottest years since 1880 have been in the last two decades.
“We’ve made the uncertainty quantification more rigorous, and the conclusion to come out of the study was that we can have confidence in the accuracy of our global temperature series,” lead author Nathan Lenssen, a doctoral student at Columbia University, said in a statement. “We don’t have to restate any conclusions based on this analysis.”
GISTEMP is calculated using ground and sea surface temperatures from 6,300 weather stations, research stations, ships, and buoys around the world. The temperatures between the stations have to be estimated and the study shows that this approach is correct.
Recently the approach was also validated using the Atmospheric Infrared Sounder (AIRS) onboard NASA's Aqua satellite. The AIRS' records only began in 2003, when Aqua launched, but it measures the temperature in a completely different way. It records infrared emissions from the surface. The fact that their methods are different and independent and they still agree is fantastic.
“Uncertainty is important to understand because we know that in the real world we don’t know everything perfectly,” said Gavin Schmidt, director of GISS and a co-author on the study. “All science is based on knowing the limitations of the numbers that you come up with, and those uncertainties can determine whether what you’re seeing is a shift or a change that is actually important.”
The trends predicted for the current and imminent damage due to the climate crisis are robust beyond what can be accounted for by uncertainties. That said, improvements on measurements leads to more detailed models and these might be life-saving shortly.