The world's climate equilibrium has been severely disturbed in the past 100 years by human industrialization. To understand the seriousness of the situation, a group of international scientists and some leading airliners are going to great heights — all the way up to 9,000m above sea level — to study just how serious climate change really is, and possibly how the situation can be turned around.
“Before the Industrial Revolution, the Earth’s carbon dioxide concentration averaged 280 parts per million [ppm] for more than 650,000 years — however, in a short 250 years, humans have managed to increase that figure to the current 380ppm,” Toshinobu Machida, chief of Japan’s National Institute for Environmental Studies Office for Atmospheric and Oceanic Monitoring, told the Taipei Times during his visit to Taipei on Tuesday.
Since 1993, Machida and his team have worked on CONTRAIL (Comprehensive Observatory Network for Trace gases by Airliners), a project that monitors greenhouse gas concentrations in the atmosphere by installing observation equipment on Japan Airlines charter flights.
“From our observations over the past decade, we have found the carbon concentration in the upper troposphere, which is 10km to 12km above sea levels, has increased at about 1.9ppm per year,” Machida said.
The phenomenon has been observed on flights that travel from the northern to the southern hemisphere [Japan to Australia], he said, adding that “since the global air current naturally goes east to west and rarely north to south, our observations indicate that the carbon increase is a global problem.”
Almost simultaneously, a group of scientists sponsored by the European Commission launched a similar project in 1993 across the Atlantic Ocean called MOZAIC (Measurement of Ozone and water vapor by Airbus In-service airCraft), which installs equipment onto Airbus aircrafts from various airlines to measure atmospheric composition.
MOZAIC was transformed in 2005 into the Integration of Routine Aircraft Measurements into a Global Observing System (IAGOS), featuring a smaller machine with better functions.
Since 1993 the two programs have contributed to a number of important findings, leading to the publication of over 180 international papers, and driving the modification of climate models, IAGOS director Andreas Volz-Thomas said.
“For example, water vapor in the upper troposphere over the Northern Atlantic was found to be much higher than previous climate models suggested — over 100 percent saturation — data that changed our understanding of cirrus clouds and persistent contrails, and how much they impacted the climate,” Volz-Thomas said.
IAGOS lent invaluable information on how quickly carbon mixes in turbulence, he added.
“While carbon in the troposphere can be mixed thoroughly by turbulence in a matter of days, it may take over a year for the gas to reach the stratosphere [10km to 50 km above ground],” he said. “Most of the carbon up there was emitted by human sources all over the world, possibly decades ago.”
Since carbon that reaches the stratosphere stays there for more than 10 years before dispersing, it can similarly seriously affect the world’s climate, Volz-Thomas said.
“And by climate, we are not just talking about temperature,” Machida said. “Climate change affects weather patterns, precipitation areas and amount, and in turn crop growth, landscape changes and human survival.”
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