In the mid 2000s, economic growth and industrial activity in Middle Eastern cities produced some of the fastest growing air pollution emissions in the world. Yet new research combining space observations with economic and energy data shows that around 2010, armed conflict, political upheaval, and economic restrictions drastically decreased air pollution in the region.
The research, published in the 21 August issue of the journal Science Advances, is among the first to highlight a link between geopolitics and atmospheric changes, and could be used to inform environmental policy in the region.
In many locations in the Middle East, the amount of atmospheric nitrogen dioxide (measured in 1015 molecules per square centimeter) declined from higher levels in 2005 and 2010 (A) to lower levels between 2010 and 2014 (B). | Jos Lelieveld
Jos Lelieveld, lead author of the study and professor at the Max Planck Institute for Chemistry, and his colleagues analyzed nitrogen dioxide, a form of air pollution caused by common byproducts of road traffic and energy production, over cities in the Middle East. They used the latest data from the Ozone Monitoring Instrument (OMI), a high-resolution satellite imager deployed into space in 2004 to detect and track specific types of air pollution.
Since the mid-1990s, nitrogen dioxide has been monitored from space, and for most of that time observations have pointed to a steady increase of this pollutant over South and East Asia and the Middle East. But Lelieveld and colleagues show that beginning in 2010, Saudi Arabia, Iran, central Iraq, and other Arabian Gulf countries, as well as Syria and Egypt, experienced startling reversals (a 10–20% decline, depending on the country) in air pollution.
Because the drop in pollution in the Middle East occurred over such a short time period and was unexpected, it couldn't have been captured by the emissions trends databases and future projections upon which the Intergovernmental Panel on Climate Change bases its recommendations, the authors of the study say.
Comparing OMI data with information from the World Bank and U.S. Energy Information Administration, the authors report a strong correlation between the dip in nitrogen dioxide emissions across the Middle East and economic recession, societal upheaval, and armed conflict, including occupation by Islamic State militants.
The authors also looked at emissions trend in other unstable regions, such as Eastern Europe and Africa, but did not notice the strong reversals in air pollution apparent in the Middle East. "The Middle East is the only region in the world where this upward trend was interrupted around 2010, followed by a rapid decline in air pollution," said Lelieveld.
It was a specific combination of air quality control in some countries such as Kuwait and Saudi Arabia, along with economical and political factors including armed conflict in other countries that drastically altered the emission landscape of nitrogen oxides in the Middle East, the authors show.
In Iran, the tightening of United Nations sanctions in 2010 led to a strong decline in air pollution, including emissions by oil tankers in the Persian Gulf. And in Syria especially, the recent civil war and other conflicts are associated with strongly declining air pollution. However, the emissions footprint of Syrian refugees has also been captured by space observations, which reveal that the spillover of displaced peoples into Jordan and Lebanon has been accompanied by sharp air pollution increases in the two countries.
Lelieveld believes the information provided in this study could be used as an additional diagnostic tool that could help researchers better analyze environmental and political trends in the Middle East.