Would You Jump to Policy Conclusions in regard to Reducing Coastal Air Pollution — Based on a Study of Only 2 Ships?

© 2012 Peter Free

 

25 October 2012

 

 

Citation — to study

 

Mohammad Yusuf Khan, Harshit Agrawal, Sindhuja Ranganathan, William A Welch, J. Wayne Miller, and David Cocker, Greenhouse Gas and Criteria Emission Benefits through Reduction of Vessel Speed at Sea, Environmental Science & Technology, DOI: 10.1021/es302371f (early online publication, 13 September 2012)

 

 

Citation — to press release

 

Michael Woods, Speed limits on cargo ships could reduce their pollutants by more than half, American Chemical Society (24 October 2012)

 

 

Predictably driving pragmatically minded business people up the wall

 

Living in an age of Rampant Nitwit-Ism means that I have become reluctantly accustomed to data being used in misleading and self-interested ways.

 

The above study is example of research that probably began honestly enough, but which has apparently been redirected to drive an (as yet) unwarranted policy conclusion.

 

Should we post the coastal seas with speed limit signs?  Read on.

 

 

First — notice who funded this statistically meaningless study and why

 

From the press release:

 

The goal of this research was to measure the emission benefits associated with greenhouse gas and criteria pollutants by operating OGVs [ocean-going vessels] at reduced speed.

 

The authors acknowledge funding from the California Air Resources Board and the U.S. Environmental Protection Agency.

 

© 2012 Michael Woods, Speed limits on cargo ships could reduce their pollutants by more than half, American Chemical Society (24 October 2012)

 

 

Notice how many ships the researchers studied — two

 

From the abstract:

 

Emissions were measured from one Panamax and one post-Panamax class container vessels as their vessel speed was reduced from cruise to 15 knots or below.

 

© 2012 Mohammad Yusuf Khan, Harshit Agrawal, Sindhuja Ranganathan, William A Welch, J. Wayne Miller, and David Cocker, Greenhouse Gas and Criteria Emission Benefits through Reduction of Vessel Speed at Sea, Environmental Science & Technology, DOI: 10.1021/es302371f (early online publication, 13 September 2012) (paragraph split)

 

A Panamax class vessel will fit through the Panama Canal.  A post-Panamax class ship will not.

 

 

Going faster burns more fuel — and creates more pollution and greenhouse gases

 

According to the press release, a supply of more than 100,000 ocean-going ships carry about 90 percent of the world’s goods.  These vessels burn low-grade fuel oil, which creates air pollution.  Going faster exponentially increases fuel consumption and emissions.

 

 

Slowing the two examined vessels decreased air pollution and greenhouse gases

 

The study of the two ships found that slowing from cruising speed to 12 knots decreased carbon dioxide emissions by 61 percent and nitrogen oxides by 56 percent (calculated in kilograms per nautical mile).  Soot pollution reportedly dropped by nearly 70 percent.

 

 

The authors’ predictable conclusion — speed limits for ships near coastlines

 

From the press release:

 

The authors suggest that imposing these speed limits on vessels near ports and coastlines could significantly reduce their pollution and protect the health of people living in those areas.

 

© 2012 Michael Woods, Speed limits on cargo ships could reduce their pollutants by more than half, American Chemical Society (24 October 2012)

 

 

Obvious caveats

 

Ships vary.  Studying the polluting characteristics of only two does not say much about the rest.

 

There was also no attempt to review the possible economic effects of slowing everything down.  Or about the economic and social consequences of enforcing new rules.

 

And nothing was said about alternative solutions, like better emission or refining technologies.  Or about the expanded enforcement establishment(s) required to carry the new impositions out.

 

Note

 

What, for example, is going to happen when a shipper decides that paying “speeding” fines is cheaper than slowing down?

 

Or when authorities seize vessels to make a point and thereby massively interfere with other companies’ ownership of the goods inside the seized vessels?

 

Yet, on this clearly inadequate study base, we have people recommending imposing speed limits at sea.

 

 

Similar to the United States’ former love affair with 55 mile per hour highway speed limit

 

We older (especially western) people remember what an insane drag that was on virtually everything we did.  And that policy began with the best of intentions.

 

 

The moral? — In an already anti-scientific culture, it makes no sense to violate the statistical validity rules of science and still call it “science”

 

Jumping to conclusions about appropriate policy, based on a study of only two ships and nothing else, is dumb.  Doing so weakens the scientific and policy credibility of the agencies involved.