The March 2011 earthquake off the coast of Japan was reportedly responsible for at least 15,000 deaths and damage to more than one million buildings, and new research indicates that effects of the catastrophic event are still being felt in the climate today.
The 9.0 earthquake, which took place in the waters off the Pacific coast of Tōhoku, also had an unseen impact on the country (and indeed, much of the world), claim the authors of a new paper published in the American Geophysical Union journal Geophysical Research Letters.
In fact, they report that the earthquake and ensuing tsunami released 7,275 tons (6,600 metric tons) of harmful greenhouse gases known as halocarbons into the atmosphere. Halocarbons can destroy the ozone layer and are stored in things like insulation and appliances, and emissions of them increased by as much as 91 percent following the earthquake, the authors wrote.
New mechanism of halocarbon emissions
According to Gizmodo, the chemicals were released from refrigerators, electrical equipment and old insulation damaged by the earthquake. Included among the halocarbons released after the incident were chlorofluorocarbons like CFC-11, a powerful ozone-depleting chemical previously used in foam insulation, and hydrochlorofluorocarbons like HCFC-22, a refrigerant that is also a powerful greenhouse gas which is reportedly in the process of being phased out.
Lead author Takuya Saito, a senior researcher at the National Institute for Environmental Studies in Tsukuba, Japan and his colleagues claim that their study is the first to examine how the quake impacted the release of halocarbons into the atmosphere, and is that it is believed to be one of the first to examine emissions of these gases following any type of natural disaster.
“What we found is a new mechanism of halocarbon emissions coming from the earthquake,” Saito said. He and his colleagues also found that the disaster also released hydrofluorocarbons (HFCs) and sulfur hexafluoride, both of which potent greenhouse gases.
Furthermore, they found that the emissions of the six halocarbons released from Japan in 2011 were equivalent to the discharge of over 1,400 tons (1,300 metric tons) of CFC-11 alone. That is equal to the amount of chlorofluorocarbons found in 2.9 million refrigerators made prior to the chemical being banned. In all, the emissions of the chemicals were equivalent to the release of 21.2 million tons (19.2 million metric tons) of carbon dioxide into the atmosphere.
Embarking on a study
Saito’s team decided to study halocarbon emissions and their relationship to the earthquake after ground-based air monitoring stations in Japan recorded unexpectedly high levels of the gases. By combining measurements from those stations with an atmospheric model and other mathematical methods, they were able to determine how much of those emissions were the result of the quake and how the emissions compared to those recorded in previous years.
They discovered that the emissions of all six halocarbons measured by the researchers were higher following the March 2011 earthquake to February 2012 than had been during the same period both before the event and after it. Nearly half of those emissions were of HCFC-22, most likely due to damage to refrigerators and air conditioners.
They found that emissions of that gas were 38 percent higher than the years before and after the earthquake, and that emissions of CFC-11 were 72 percent higher than those recorded before and after the earthquake – likely because insulation foams used in appliances and buildings had been damaged. Emissions of two types of HFCs (HFC-134a and HFC-32) increased by 49 percent and 63 percent, respectively, compared to the years before and after the disaster.
The researchers also calculated the total impact of the increased emissions on ozone depletion and global warming, and found that the earthquake-triggered increase in halocarbons increased ozone loss from Japanese emissions of those gases by 38 percent during the one-year period following the earthquake compared to the years before and after the event, and the amount of heat trapped in the atmosphere due to those gases increased by 36 percent.