Our directory of things of interest

University Directory

Exhausts from shipping lanes worsen lightning storms

Storms, ships and the South China Sea Storms, ships and the South China Sea Shutterstock
15 Sep
2017
Shipping traffic can increase lightning strikes, according to a pioneering study by the American Geophysical Union

Skies studied over two of the world’s busiest shipping lanes experienced twice as much lightning as the open ocean around them, according to researchers from the University of Washington and the American Geophysical Union. Their findings provide some of the best evidence yet that human activity is altering cloud activity on a continual basis. ‘It’s one of the clearest examples of how humans are actually changing the intensity of storm processes on Earth through the emission of particulates from combustion,’ says Joel Thornton lead author of the study and atmospheric scientist at the University of Washington.

Clouds are formed when water condenses around aerosols – tiny airborne particulates. Fewer aerosols in the air will create larger, warmer cloud droplets that turn into rain, while more aerosols have the effect of shredding water into smaller cloud droplets. These smaller droplets create lightning by being lifted to higher altitudes, freezing, and then generating a positive electric charge. As the ships pass, it is thought they are pumping small aerosol particles into the air, ‘seeding’ cloud droplets that are more prone to lightning production. ‘These particles act as the nuclei on which cloud drops form and can change the vertical development of storms, allowing more cloud water to be transported to high altitudes, where electrification of the storm occurs to produce lightning,’ writes Thornton.

grl56360 fig 0001Annual lightning density from 2005 to 2016 (top) compared to shipping emissions for 2010 (bottom) (Image: Johnson et al)

The data was collected from lightning storms experienced in the Indian Ocean and the South China Sea between 2005 and 2017, and showed that lightning occurred twice as often in the skies above the ships. By comparing the skies above shipping lanes to non-shipping lanes that were directly adjacent and running parallel to them, the team was able to rule out other factors that might have accounted for more lightning. Mapping the difference, it was found that increased lightning followed the ‘same angular paths’ of the shipping lanes, often with a correlation that was so clear, the lightning maps directly resembled the shipping maps. ‘All we had to do was make a map of where the lightning was enhanced and a map of where the ships were travelling and it was pretty obvious just from the co-location of both of those that the ships were somehow involved in enhancing the lightning,’ says Thornton.

The team also found that lightning strikes seem to increase over the years, especially in the South China Sea. By looking at port activity records, they found this increase correspondended to an increase in shipping  - the tonnage coming in and out of Singapore had almost doubled over the same time period. 

Because shipping lanes inject aerosols to otherwise remote areas of open ocean, the maps are a clear-cut example of how human combustion can be directly altering the weather. The team concludes that: ‘our findings suggest that even small absolute increases in remote marine aerosol particles due to human activities could have a substantial impact on storm intensity and lightning.’

Related items

Subscribe and Save!

geo line break v3

Free eBooks - Geographical Newsletter

Sign up for our weekly newsletter today and get a FREE eBook collection!

geo line break v3

University of Winchester

geo line break v3

EDUCATION PARTNERS

Aberystwyth University University of Greenwich The University of Derby

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

NEVER MISS A STORY - Follow Geographical on Social

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in NATURE...

Oceans

A ship that ran aground early in February has been…

Wildlife

Two whale populations on either side of the African continent…

Geophoto

March traditionally heralds the beginning of spring, a time of…

Wildlife

An innovative project to utilise Laos’ elephant experts in service…

Polar

Despite common belief that Antarctica is vastly uninhabited, humans are…

Wildlife

Javan rhinos survived the recent Krakatoa tsunami, but the species…

Energy

As the world turns away from fossil fuels, one question…

Geophoto

The winners of the Outdoor Photographer of the Year 2018…

Climate

New legislation in Florida aims to solve various environmental issues,…

Polar

The world’s magnetic model is getting an early update, as…

Climate

Marco Magrini looks at the financial pressures spilling out into the…

Geophoto

Few sights are more dramatic than a star-filled sky at…

Polar

A region of Antarctica previously known for relative stability is…

Tectonics

Everything we thought we knew about eruptions could be wrong

Oceans

Sea levels are rising across the globe, but along the…

Polar

Seismometers buried in the Ross Ice Shelf have revealed that…

Wildlife

A tightening of restrictions on the insecticides known as neonicotinoids…

Wildlife

Bonnethead sharks, the second smallest member of the hammerhead family,…

Nature

There’s more than enough plastic in the world. That’s why,…

Wildlife

The recent discovery of more than 200 million termite mounds…