Global Challenges/Chemistry Solutions

Confronting Climate Change: Stop-Gap Measures to Reduce Greenhouse Gas Emissions: Speed limits on cargo ships could reduce their pollutants by more than half

December 10, 2012

Cargo ship
Speed limits on cargo ships could reduce their pollutants by more than half.
iStockphoto/Thinkstock

Summary

Putting a speed limit on cargo ships as they sail near
ports and coastlines could cut their emission of air
pollutants by up to 70 percent, reducing the impact of
marine shipping on Earth’s climate and human health,
scientists have found. Their evaluation of the impact
of vessel speed reduction policies appears in ACS’
journal Environmental Science & Technology.

Today’s report concludes that putting a speed limit on cargo ships as they sail near ports and coastlines could cut their emission of air pollutants by up to 70 percent. That would reduce the impact of marine shipping on Earth’s climate and on human health, the scientists say. Their evaluation of the impact of vessel speed reduction policies appears in ACS’ journal Environmental Science & Technology.

David R. Cocker III, Ph.D., who is with the University of California, Riverside, explains that marine shipping is the most efficient form of transporting goods, with more than 100,000 ships carrying 90 percent of the world’s cargo.

“The problem is that the engines on these vessels burn a low-grade oil that produces large amounts of air pollution. Because fuel consumption and smokestack emissions increase exponentially with speed, we explored how speed limits could reduce pollution.”

They found that slowing container ships to about 14 miles per hour reduced emissions of carbon dioxide by about 60 percent and nitrogen oxides by 55 percent compared to emissions at traditional cruising speeds of 25-29 miles per hour. Soot emissions fell by almost 70 percent.

“We suggest that imposing lower speed limits on vessels near ports and coastlines could significantly reduce their pollution and protect the health of people living in those areas.”

Smart Chemists/Innovative Thinking

Smart chemists. Innovative thinking. That’s the key to solving global challenges of the 21st Century. Please check out more of our full-length podcasts on wide-ranging issues facing chemistry and science, such as promoting public health, developing new fuels and confronting climate change, at www.acs.org/GlobalChallenges Today’s podcast was written by Katie Cottingham. I’m Sam Lemonick at the American Chemical Society in Washington.

David R. Cocker III, Ph.D.
David R. Cocker III, Ph.D.,
University of California, Riverside
Riverside, California