Fatal lightning strikes set to soar because of climate change
Fatal lightning strikes are set to soar because of climate change, according to new research.
As the world gathers for COP26 in Glasgow, scientists have unveiled a tool to save lives threatened by increasingly lethal thunderstorms.
It reveals if humans or animals were the victims of a bolt from the heavens – based solely upon an analysis of lightning’s ‘fingerprint’ in their skeletons.
Lead author Dr Nicholas Bacci, of Wits University in Johannesburg, said: ‘Identifying a fatality caused by lightning strike is usually done though marks left on the skin, or damage to the internal organs – and these tissues don’t survive when bodies decompose.
‘Our work is the first research that identifies unique markers of lightning damage deep within the human skeleton and allows us to recognise lightning when only dry bone survives.
‘This may allow us to recognise accidental death versus homicide in cases where cause is not apparent, whilst at the same time allowing us to build a more complete picture of the true incidence of lightning fatalities.’
Lightning kills at least 24,000 people a year – a conservative estimate expected to increase by around 12 percent in the coming decades.
In experiments, artificial lightning was generated in the laboratory and applied to bones donated by people who had died of natural causes.
Co-author Dr Hugh Hunt, also from Wits, said: ‘We used equipment to generate high impulse currents in the lab, (up to 10,000 Amps), which mimicked the effect of lightning passing through the skeleton.
‘Natural lightning can often have significantly higher peak currents but this allowed us to have much greater control over the experiment than trying to somehow place human tissue in the path of a natural lightning strike.’
A pattern of damage was identified that was uniquely caused by short duration lightning current.
Senior author Dr Patrick Randolph-Quinney, of Northumbria University, explained: ‘Using high-powered microscopy we were able to see that there is a pattern of micro-fracturing within bone caused by the passage of lightning current.
‘This takes the form of cracks which radiate out from the centre of bone cells, or which jump irregularly between clusters of cells.
‘The overall pattern of damage looks very different when compared to other high energy trauma, such as that caused by burning in fire.
‘Even though this experiment was conducted under controlled conditions in the lab, we see the same trauma in animals killed by natural lightning.
‘We were able to compare the human results with bone from a poor giraffe killed by lightning – and the pattern of trauma is identical even though the micro-structure of human bone is different from animal bone.
‘This is the smoking gun that we were looking for in forensic lightning pathology.’
It’s hoped the study will make the environment safer for those at risk of being killed by lightning.
Lightning is one of the most spectacular – and destructive – events in nature. They can bring down buildings – and spark forest fires.
A single lightning bolt is made up of several 100 million volts, while the Met Office reports that they travel at a speed of 270,000 mph.
They can also reach a temperatures of 30,000 °C – five times hotter than the surface of the sun.
African countries, among them Zambia and Uganda, have some of the highest lightning fatality rates in the world.
In South Africa, more than 250 people are killed by lightning annually. The exact number of deaths globally isn’t clear, due to under reporting.
They can’t always be definitely attributed to lightning because, while its marks are easy to spot on the skin or in the organs, nobody was sure how to identify telltale signs on skeletonised remains.
Co-author Prof Ken Nixon, also from Wits, said: ‘This is a multi-disciplinary project, which highlights how forensic scientists can work with physicists and engineers to explore a real-world problem, which is implicated in the deaths of many people annually, and especially in countries such as South Africa, Zambia and Uganda.
‘At a time when global climate change is driving increases in the number and severity of thunderstorms and lightning strikes, we need more research like this, bringing together different fields with real experience of dealing with lightning.
‘Ultimately our aim at Wits is to make our built environment and countryside safer for those exposed to the lethal effects of lightning energy in South Africa, and to provide life-saving knowledge for those around the globe who are increasingly put in harm’s way of this natural phenomenon.’
The chance of getting struck by lightning is pretty slim in the UK – up to 10 million to one.
The Royal Society for the Prevention of Accidents states 30 to 60 people are struck by lightning each year in Britain, and on average, three (5-10%) are fatal.
The study is in the journal Forensic Science International: Synergy.