Major correction to satellite data shows 140 percent faster warming since 1998, erasing global warming “hiatus”

Desdemona Despair

By Zeke Hausfather
30 June 2017

(CarbonBrief) – A new paper published in the Journal of Climate reveals that the lower part of the Earth’s atmosphere has warmed much faster since 1979 than scientists relying on satellite data had previously thought.

Researchers from Remote Sensing Systems (RSS), based in California, have released a substantially revised version of their lower tropospheric temperature record.

After correcting for problems caused by the decaying orbit of satellites, as well as other factors, they have produced a new record showing 36% faster warming since 1979 and nearly 140% faster (i.e., 2.4 times larger) warming since 1998. This is in comparison to the previous version 3 of the lower tropospheric temperature (TLT) data published in 2009.

Climate sceptics have long claimed that satellite data shows global warming to be less pronounced than observational data collected on the Earth’s surface. This new correction to the RSS data substantially undermines that argument. The new data actually shows more warming than has been observed on the surface, though still slightly less than projected in most climate models. [more]

Major correction to satellite data shows 140% faster warming since 1998

ABSTRACT: Temperature sounding microwave radiometers flown on polar-orbiting weather satellites provide a long-term, global-scale record of upper-atmosphere temperatures, beginning in late 1978 and continuing to the present. The focus of this paper is a lower-tropospheric temperature product constructed using measurements made by the Microwave Sounding Unit channel 2, and the Advanced Microwave Sounding Unit channel 5. The temperature weighting functions for these channels peak in the mid to upper troposphere. By using a weighted average of measurements made at different Earth incidence angles, the effective weighting function can be lowered so that it peaks in the lower troposphere. Previous versions of this dataset used general circulation model output to remove the effects of drifting local measurement time on the measured temperatures. In this paper, we present a method to optimize these adjustments using information from the satellite measurements themselves. The new method finds a global-mean land diurnal cycle that peaks later in the afternoon, leading to improved agreement between measurements made by co-orbiting satellites. The changes result in global-scale warming (global trend (70S-80N, 1979-2016) = 0.174 C/decade), ~30% larger than our previous version of the dataset (global trend, (70S-80N, 1979-2016) = 0.134C/decade). 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 data. However, comparisons with total column water vapor over the oceans suggest that the new dataset may not show enough warming in the tropics.

A satellite-derived lower tropospheric atmospheric temperature dataset using an optimized adjustment for diurnal effects