- According to a study by nasa, the changes in the imo policy and the lower levels of shipping traffic during covid-19 reduced air pollution.
- Researchers from NASA called earth- observation aqua satellite MODIS to take up images of the shipping Tracks.
- During the pandemic global shipping traffic fell by 1.4 %.
According to a NASA AI model, reducing sulphur in shipping fuel reduced sea-level air pollution to the lowest levels this century in 2020. Of course, the COVID-19 pandemic aided in this as well.
IMO policy
The International Maritime Organization’s (IMO) rule limiting the sulphur content of fuel oil for ships travelling outside emission-control areas went into effect two years ago.
The restriction was expected to reduce sulphur dioxide emissions by 77%, or 8.5 million metric tonnes. The carcinogenic gas raises the risk of acid rain and can cause respiratory, cardiovascular, and lung disease.
Shipping traffic
According to a NASA study, the IMO 2020 policy – and lower levels of shipping traffic during the early stages of the COVID-19 pandemic – reduced shipping air pollution to the lowest levels since tracking began nearly 20 years ago.
Researchers created an AI model to identify shipping tracks in images taken by NASA’s Earth-observation Aqua satellite’s Moderate Resolution Imaging Spectroradiometer instrument (MODIS) from 2003 to 2020.
Pollutant aerosols
“We cannot begin to understand this problem without this kind of complete and large-scale sampling of ship tracks,” Tianle Yuan, an atmospheric scientist at NASA’s Goddard Space Flight Center and the University of Maryland, said Tuesday. The findings of the study were recently published in Science.
The images showed what the model initially identified as anomalous cloud lines. Pollutant aerosols emitted by ships combine with water vapour to form these clouds. The concentrated droplets scatter more light and appear brighter than other types of sea clouds with larger salt particles.
Ship-track density
When the amount of sulphur in fuel was capped in 2020, the model helped researchers realise that ships began to produce less air pollution.
The paper notes that “Ship-track density experiences strong decreases in every detected major shipping lane compared to climatology and reaches record lows in the nearly 20-year data record.”
Steeper decline
“Other shipping lanes, aside from the trans-Pacific and trans-North Atlantic, are no longer discernible. When compared to the climatological mean, annual mean ship-track density decreases by 50% or more in five major shipping lanes. When compared to 2019, the decline is even steeper.”
Fuel regulation
During the COVID-19 pandemic, global shipping traffic fell by 1.4 percent for a few months and remained low in 2021, though the fewer vessels did not account for the large drop in detected shipping tracks. The researchers believe the IMO 2020 fuel regulation had a greater impact on reducing air pollution.
Global trade
They were also able to trace popular shipping routes across Asia and America at various times, such as the drop in global trade after the 2008 financial crisis. Between 2014 and 2016, there were two other drops in Asian shipping traffic as China imported and exported fewer resources.
Radiation emission
“Ship tracks are excellent natural laboratories for studying the interaction between aerosols and low clouds, as well as how this affects the amount of radiation that Earth receives and reflects back to space. That is a major uncertainty in terms of what drives climate right now,” Yuan said.
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Source: The Register
