Azadeh Tabazadeh

Azadeh Tabazadeh is an Iranian geophysicist and author known for her work in atmospheric science, work which has improved our understanding of the reactions that affect ozone depletion and highlighted the impact human activity has on the atmosphere.

Tabazadeh grew up in Tehran, Iran, raised by her father Modjtaba, and her mother, Azar. Her father worked as an engineer in civil construction and so the family was financially well supported. In 1973, when she was 8 years old, she received a chemistry set as a present for Nowruz, from her uncle, a Geology student. She also received the memoirs of Marie Curie which showed her for the first time that women could be successful scientists. She cites these presents as key moments in developing her passion for science.

Tabazadeh was 14 when Ayatollah Khomeini overthrew Shah Reza Pahlavi in Iran and implemented Sharia law in 1979. The strict regime completely changed the lives of Tabazadeh and her family . In 1982, following the start of the Iran-Iraq war, Tabazadeh persuaded her parents to send her abroad so she could pursue science , which was nowimpossible under Ayatollah’s rule. Her parents paid $44,000 to hire drug lords and human traffickers to send the then 17 year old and her brother, Afshan, out of the country. They travelled across the Pakistani desert to Karachi, to London, Madrid, and eventually Los Angeles, California. Their parents and younger sister stayed behind.

After arriving in the US, Tabazadeh lived in Mountain View with her mother’s friend and studied English. She later attended University of California, Los Angelesearning both her bachelor’s and master’s degrees in chemistry.

Tabazadeh continuedat UCLA for a doctorate in physical chemistry, awarded in 1994. Part of her work aimed to understand the contributions of volcanic eruptions to chlorine levels in the stratosphere. Chlorine is known to contribute to ozone depletion in the stratosphere. Although volcanic gases contain large amounts of chlorine, she found that this chlorine precipitated before it reached the stratosphere, implying that human activity was still the major contributor of chlorine in the upper atmosphere. Her work was vital in ending 20 years on debate around this topic and supported the value of measures, such as the Montreal Protocol in reducing chlorine emissions.

During her doctoral studies she also contributed to an improved understanding of why the Antarctic atmosphere was more affected by ozone depletion than the Arctic. She showed that the colder temperature of the Antarctic stratosphere allowed for certain reactions to take place, leading to the loss of ozone; this was not the case in the warmer Arctic stratosphere. This led her to conclude that increasing surface temperatures of the Earth, and therefore decreased stratospheric temperatures, could lead to more ozone depletion. This made her one of the first scientists to make the link between ozone depletion and global warming. Her contributions were recognised by NASA who decided to underwrite some of her tuition fees as a result.

After her finishing her PhD, Tabazadeh moved to work at the NASA Ames Research Centre. She continued to work on polar stratospheric clouds and their role in stratospheric chemistry. Her work showed that denitrification in the stratosphere was an important factor in ozone loss. She also made additional contributions to understanding ice formation and removal of nitric acid in the upper troposphere.

She visited the White House in 1999 as a recipient of the Presidential Early Career Award for Scientists and Engineers under the Clinton administration. She was also awarded the James B. Macelwane Medal from the American Geophysical Union in 2001 for “significant contributions to the geophysical sciences by young scientists of outstanding ability”. She automatically became a Fellow of the Union as a result.

In 2004 Tabazadeh left NASA to become a visiting professor at Stanford University where she worked on potential atmospheric impact of using hydrogen rather than fossil fuels as an energy source. She left Stanford in 2011 to write her memoirs.

Selected publications

• Tabazadeh, A., & Turco, R. P. (1993). Stratospheric chlorine injection by volcanic eruptions: HCI scavenging and implications for ozone. Science, 260(5111), 1082-1086.
• Tabazadeh, A., Santee, M. L., Danilin, M. Y., Pumphrey, H. C., Newman, P. A., Hamill, P. J., & Mergenthaler, J. L. (2000). Quantifying denitrification and its effect on ozone recovery. Science, 288(5470), 1407-1411.

Tabazadeh started writing stories after her interview with TIME magazine in 2005, realising that people were interested in her personal story as well as her research. She attended writing classes to work on her memoirs and eventually won a $38,000 prize from the San Francisco Writer’s Conference. This allowed her to self-publish her memoir ‘The Sky Detective’. Her memoirs focus on the Islamic Revolution in Iran from the perspective of her younger self.

Tabazadeh has 3 children.

• Presidential Early Career Award for Scientists and Engineers (1999)
• James B. Macelwane Medal, American Geophysical Union (2001)
• Fellow of the American Geophysical Union (2001)
• NASA Exceptional Scientific Achievement Medal (2001)
• Popular Science Brilliant 10 (2002)
• Henry G. Houghton Award, American Meteorological Society (2003)