Dr. Zeke Hausfather says that satellite data proved the Earth is not warming as fast as thought. Climate change sceptics have long pointed to satel
Dr. Zeke Hausfather says that satellite data proved the Earth is not warming as fast as thought.
Climate change sceptics have long pointed to satellite data showing lower temperatures than those recorded on the ground.
Nonetheless, this discrepancy is explained by new research.
By cause of friction in the Earth’s atmosphere, the orbit of satellites around the Earth gradually decays over time, and this changes the time they pass over any one spot, and this apparently has a substantial effect on the temperature.
Basing on data from the satellites, Dr Carl Mears and Frank Wentz, scientists of Remote Sensing Systems, research company from California, invented a new method of correcting for the changes.
Their results were shocking.
Compared to 0.134C per decade, the rate of warming between 1976 and 2016 was approximately a third higher, at 0.174C per decade.
“The changes result in global-scale warming … about 30 % greater than our previous version of the dataset,”” scientist wrote in the Journal of Climate.
“This change is primarily due to the variations in the adjustment for drifting local measurement time. The new data set presents more warming than most related datasets constructed from satellites or radiosonde data.”
Data scientist Dr Zeke Hausfather wrote in an article on the Carbon Brief website about the new research that there is the even faster rate of warming since 1998 – at nearly 140 per cent – contrary to former satellite-based studies.
“Climate cynics have long insisted that satellite data shows global warming to be less clear that observational data gathered on the Earth’s surface,” he said.
“This new correction to the data substantially undermines that argument. The new data shows more warming than has been observed on the surface, though still slightly less than predicted by most climate models.”
The problem with interpreting weather data from satellites due to their subtly changing orbit was explained by Dr Hausfather.
“As the satellites circle the Earth, their orbits gradually decay over time,” he wrote.
While the satellites are created to fly over the same exact spot on the Earth at the identical time every day – a precondition to accurately assessing changes in temperatures over time – this orbital decay makes their flyover time to change.
Some satellites have relatively large orbital drifts, going from measuring temperatures at 2 pm to 6 pm or 8 pm.
Since the temperature differences from 1979 are on the order of 0.6C or so, it is almost easy for bias, due to varying observation times, to swamp the underlying climate signal.
Consequently, it is not too shocking that corrections to difficulties with satellite data would move them closer to surface records.