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10 July 2017

Corrections to Satellite Temperature Data Confirm Heightened Global-scale Warming

Despite the abundance of evidence available to the contrary, there are still many individuals out there who refuse to accept that global warming is in fact very real, and is sure to have some pretty dire consequences for the world at large if left to progress unchecked. When making their arguments, these sceptics have long relied upon an apparent discrepancy in temperature data, specifically between temperatures taken on the ground and those measured by satellite. The data from said satellites appears to show lower global temperatures than those acquired via ground-based facilities, but scientists now think they can better explain from where this discrepancy arose and make the necessary corrections.

The orbit of satellites tasked with taking these measurements is known to diminish over time due friction in the Earth’s atmosphere, resulting in a scenario whereby the time at which they pass over and subsequently take measurements from any one spot will change, and by extension this has a notable effect on temperature readings. As I said, this issue has been known for some time, but the methods of accurately correcting for this scenario are still being refined.

It is in this specific regard that a recent study conducted by Dr Carl Mears and Frank Wentz, of Remote Sensing Systems, claims to have made a breakthrough. The study, published in the Journal of Climate, successfully developed a new method of correcting for the changes in satellite orbits and thereby improving the accuracy of satellite temperature measurements. After making these necessary changes, the figures become rather alarming.

The researchers found that the rate of warming across the globe is on average around a third higher than previously thought, sitting at 0.174°C per decade between 1976 and 2006. Previous data placed this figure at 0.134°C. That may not sound like much, but these relatively small numbers soon add up over time to constitute quite the dramatic rise in global temperatures.

The researchers state within the report, “The changes result in global-scale warming about 30 per cent larger than our previous version of the dataset. 

“This change is primarily due to the changes in the adjustment for drifting local measurement time. The new dataset shows more warming than most similar datasets constructed from satellites or radiosonde [weather balloon] data.”

In an article concerning the new research posted to the Carbon Brief website, data scientist Dr Zeke Hausfather offered further insight into how satellite orbits can impact upon the data collected. He explained, “As these satellites circle the Earth, their orbits slowly decay over time due to drag from the upper atmosphere.

“While the satellites are designed to fly over the same spot on the Earth at the same time every day – a precondition to accurately estimating changes in temperatures over time – this orbital decay causes their flyover time to change.

“Some satellites have fairly large orbital drifts, going from measuring temperatures at 2pm to 6pm or 8pm.

“Since the temperature changes since 1979 are on the order of 0.6C or so, it is relatively easy for bias, due to changing observation times, to swamp the underlying climate signal.”

Dr Hausfather further stated that the results appear to show an even faster rate of warming since 1998, at around 140% of that suggested by previous satellite-based studies.

“Climate sceptics have long claimed that satellite data shows global warming to be less pronounced that observational data collected on the Earth’s surface,” he said.

“This new correction to the data substantially undermines that argument. The new data actually shows more warming than has been observed on the surface, though still slightly less than predicted in most climate models.”

Sam Bonson

Sam is an aspiring novelist with a passion for fantasy and crime thrillers. He is currently working as a content writer, journalist & editor in an attempt to expand his horizons.