From Australian bushfires to Haitian earthquakes, social media platforms are proving to be flexible tools in spreading life-saving information about impending disasters and vital aid after an event, but how to use them wisely remains a vexed question.
A new study from the US focuses on the use of the online news and social networking platform Twitter during natural disasters and has found that average users with relatively small numbers of followers are more effective at spreading useful information than high-profile so-called “influencers” who boast massive numbers of followers.
Additionally, the research, published in the journal PLOS One, finds each type of natural disaster has its own unique pattern of social media use.
The authors, led by Meredith Niles from the University of Vermont, note that extreme events caused by climate change will likely become more frequent and severe. Using social media to get the word out about disaster preparation and recovery has become a critical point of scrutiny for climate change adaptation.
The study looks into how information is disseminated in emergencies, and by who, and is the first to examine social media patterns across different disaster types – hurricanes, floods and tornadoes – focussing on Twitter usage during five of the costliest weather and climate emergencies, excluding long-term droughts, in the US between 2011 and 2016.
The study looks at Twitter data from Hurricane Sandy, in October 2012; Hurricane Irene, in August 2011; tornadoes that swept across the south-east and midwest in April 2011; Louisiana flooding in August 2016; and the tornado “super outbreak” in the midwest and south-east in May 2011.
It uses data from the National Centres for Environmental Information in the National Oceanic and Atmospheric Administration (NOAA), which categorises the economic costs of weather and climate disasters.
The study cites 2017 estimates from the Pew Research Centre, that 77% of people in the US owned and used smartphones, giving “unprecedented and immediate access to people for rapidly consuming and producing information”.
Further, it says, 80% of social media use occurs via mobile technologies, 24% of people in the US, about 68 million people, use Twitter, and that social media is “increasingly changing the way society communicates before, during and after disaster events”.
“We show that social media use differs markedly depending on emergency type, and these insights can help with emergency planning, where effective communications can be a matter of life and death,” says Niles.
Never mind the celebrity social media “influencers” with millions of followers. In a natural disaster, average Twitter users, those with 100 to 200 followers, are found to be more active disseminators of useful information.
“We found average Twitter users tweeted more frequently about disasters, and focused on communicating key information,” says study co-author Benjamin Emery.
He says these average users tend to have more friends and family as followers, which makes for close-knit networks that are more likely to seek and exchange useful information in emergencies.
The study suggests it would be more effective to target average users with meaningful networks, with compelling, accurate messages that average people will feel compelled to share in the “social wild online”.
Meanwhile, the researchers found key differences in tweet timing and volume, depending on disaster type. For hurricanes, people tweeted more frequently about emergency topics before the event, but for tornadoes and floods, which occur with less warning, Twitter was used for real-time or recovery information.
The study suggests that the importance of Twitter for communicating potentially life-saving information could be maximised by tailoring the timing and content of messages to the emergency type.
“We show that people are much more active on Twitter just before a hurricane, when they know it’s coming and they are preparing,” Niles says.
The researchers found activity dropped during the actual event, which, Niles says, “suggests that Twitter is most effective as a tool to communicate preparation or evacuation information in advance of hurricanes”.
But when an unexpected hazard such as a tornado or flood strikes, they found people were tweeting in real time as the situation unfolded.
“ln the case of floods and tornadoes, it appears people are using Twitter to share critical information about resources in the immediate aftermath and recovery period,” says Niles.
Given the importance of food and water during natural disasters, the researchers tracked 39 key words related to emergencies, food security, water and resources, and analysed their frequency and volume across Twitter over the two weeks surrounding each event.
For example, terms such as “groceries”, “supermarket” and “prepare” were most frequently used before hurricanes, but “shelter”, “emergency”, “wind” and “food security” were used during and after tornadoes. This suggests people are communicating about their preparation or recovery in real-time and sharing resources that could assist those seeking help.