If melting ice caps won't convince climate change deniers that the planet is in trouble, maybe proving that the Earth literally has a hotspot will do the trick.
In a study published in the journal Environmental Research Letters, climate scientists confirmed that the upper troposphere is exhibiting strong warming. Colloquially referred to as the tropospheric hotspot, the warming has long been expected as part of the theory on global warming, as such appearing in a lot of climate models. However, as the hotspot has not been detected before, deniers used that to challenge the reality of global warming and climate change.
Steve Sherwood, chief investigator for the ARC Centre of Excellence for Climate System Science and lead author for the study, explained that he and his colleague Nidhi Nishant used improved methods of analysis and more recent data to reexamine radiosondes, or the global weather balloon network. Doing so showed that there are clear indications that the upper troposphere is warming.
Sherwood and Nishant used publicly-available wind and temperature data on the upper troposphere collected between 1958 and 2012. The climate scientists didn't use climate models for the study but instead turned to observations, combining two techniques: Kriging and linear regression. They used available data to deduce what climate and weather variations would naturally look like, discovering anomalies. Removing the anomalies resulted in more accurate data, which paved the way for discovering the tropospheric hotspot.
The results of the study support the claim that global warming has slowed down, but the researchers pointed out that it only applies to the Earth's surface. Throughout the troposphere, warming continued strongly, except for a thin layer about 8.7 to 9.3 miles from above the surface of the planet.
Aside from confirming the presence of the tropospheric hotspot, Sherwood and Nishant also discovered that there was a 10 percent increase in wind speed over the Southern Ocean, a finding that is suggestive of ozone depletion. The researchers are interested in exploring these increases in wind speed to determine if they have a role in slowing down warming in ocean surfaces.
"One thing this improved data set shows us is that we should no longer accept the claim that there is warming missing higher in the atmosphere. That warming is now clearly seen," said Sherwood.
A major initiative financially supported by the Australian Research Council, the ARC Centre of Excellence for Climate System Science involves five Australian universities and a host of national and international partner organizations.
Photo: John LeGear | Flickr
