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.’

Share this story...

Submit to FacebookSubmit to Google PlusSubmit to Twitter

Related items

Geographical Week

Get the best of Geographical delivered straight to your inbox every Friday.

Subscribe Today

EDUCATION PARTNERS

Aberystwyth UniversityUniversity of GreenwichThe University of Winchester

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

DOSSIERS

Like longer reads? Try our in-depth dossiers that provide a comprehensive view of each topic

  • The Air That We Breathe
    Cities the world over are struggling to improve air quality as scandals surrounding diesel car emissions come to light and the huge health costs of po...
    Diabetes: The World at Risk
    Diabetes is often thought of as a ‘western’ problem, one linked to the developed world’s overindulgence in fatty foods and chronic lack of physi...
    The Nuclear Power Struggle
    The UK appears to be embracing nuclear, a huge U-turn on government policy from just two years ago. Yet this seems to be going against the grain globa...
    National Clean Air Day
    For National Clean Air Day, Geographical brings together stories about air pollution and the kind of solutions needed to tackle it ...
    REDD+ or Dead?
    The UN-backed REDD+ (Reducing Emissions from Deforestation and Forest Degradation) scheme, under which developing nations would be paid not to cut dow...

MORE DOSSIERS

NEVER MISS A STORY - follow Geographical

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...

Wildlife

Nature reserves and protected areas in Germany have lost 76…

Oceans

An investigation into shark fins and ray gills sold in…

Climate

Geographical’s regular look at the world of climate change. This…

Wildlife

The rapid spread of Asian hornets is likely to make…

Energy

Europe provides more than €112billion (£97billion) in subsidies to fossil…

Oceans

A study of various fish populations has found dramatic reductions…

Geophoto

The seasonal changes of September promise much photographic potential for…

Oceans

Shipping traffic can increase lightning strikes, according to a pioneering…

Polar

New documentary travels to remote Antarctica to unpack the complex…

Oceans

The deaths of these majestic creatures had remained an unsolved…

Wildlife

Over a two-year period, a new species of plant or…

Wildlife

As part of New Zealand’s plan to cull millions of…

Oceans

A project to map the ocean floor is raising concerns…

Climate

Geographical’s regular look at the world of climate change. This…

Wildlife

Dismay as a Spanish baby dolphin becomes the latest victim…

Polar

Geographical’s regular look at the world of climate change. This…

Oceans

The effect of plastics on the world’s oceans is posing…

Geophoto

Camera technology may have come a long way since the…

Energy

The UK appears to be embracing nuclear, a huge U-turn…

Wildlife

Despite their high profiles, most of the world’s national animal…