A lot of scientific research happens in windowless laboratories, behind glowing computer screens, and out in remote fields and forests. But when scientists publish their work, they let the world in on what they've found.
A new scientific study can captivate the public imagination, stoke vibrant discussion, or even change public policy. Such was the case for a few of the most talked-about scientific findings of the year.
The following list of the top 10 science findings of 2018 comes from the data crunchers at Altmetric, who analysed how much various research papers got discussed on science blogs, social media, and in published news stories. They also took into account which studies were cited in Wikipedia entries and how many of them informed public policy.
The research in the resulting top 10 list looked into our diets, the planet's health, and even the way fake news spreads online. Here are the most influential and talked-about studies of 2018.
The team, led by researchers from the Harvard T.H. Chan School of Public Health, went house to house in remote and urban areas of Puerto Rico. They asked people if anyone at their home had died during - or as a result of - the hurricane.
Those surveys led the researchers to estimate that the true death toll from Maria on the island could be as low as 793 or as high as 8,498. Either way, that was far more than the death toll of 64 that the government had reported.
Not all of Maria's victims were killed right when the Category 4 storm slammed into the island.
The research team, whose results were published in the New England Journal of Medicine, said at least a third of the deaths happened after the storm hit, since people couldn't get life-saving care amid the destruction.
Surprise and disgust are both powerful emotions, and they're effective motivators when it comes to the spread of fake news and misinformation.
Researchers from MIT examined 126,000 Twitter posts, tweeted by 3.5 million users between 2006 and 2017. They found that a false post spreads to 1,500 new eyeballs six times as fast as the truth. Their results also showed that lies were 70% more likely to be retweeted, no matter how many followers the account had and regardless of whether it was verified.
"Humans, not robots, are more likely to spread it," the researchers wrote in the journal Science.
They think there may be a simple reason why fake news is more appealing than the truth: It's shiny and new.
"We found that false news was more novel than true news, which suggests that people were more likely to share novel information," the researchers said. "Whereas false stories inspired fear, disgust, and surprise in replies, true stories inspired anticipation, sadness, joy, and trust."
The authors of a major study published in the Lancet found that, around the world, the more people drink, the more likely they are to develop cancer and the more likely they are to die.
The research caused a stir, since the authors suggested that there is no safe level of alcohol. Journalists around the world quickly picked up that headline and ran with it.
But there is some evidence that a moderate amount of booze (say, one drink per day) can help protect against some health conditions, notably heart disease and diabetes. The lead author of the Lancet study, Max Griswold from the University of Washington, said that doesn't matter because "combined health risks" associated with alcohol increase "with any amount of alcohol."
Others aren't so sure.
"Just because something is unhealthy in large amounts doesn't mean that we must completely abstain," Professor Aaron Carroll from Indiana University School of Medicine wrote for The New York Times after the study was published.
It's also important to remember that Griswold's finding wasn't based on entirely new research. Instead, his team reviewed nearly 600 previous studies on alcohol for a meta-analysis. Meta-analyses can make it hard to control for accuracy, since different researchers perform studies in dramatically different ways.
Plus, other unmeasured factors could also account for increases in deaths and health problems in drinkers. People who consume alcohol might be stressed, smoke, or have other underlying health issues or genetic differences that make them more likely to develop diseases.
"We could spend lifetimes arguing over where the line is for many people," Carroll wrote. "The truth is we just don't know."
"If this were to happen, the world would become far warmer than it's been for at least the past 1.2 million years," Business Insider's Kevin Loria wrote when the paper came out in Proceedings of the National Academy of Sciences in August. "Sea levels around the globe would likely rise between 10- and 91m higher than they are now."
The ripple effect of that warming would be felt around the globe. Permafrost that's trapping in greenhouse gases near the poles would thaw, the world's ice sheets would melt, and the Amazon rainforest (known as the "lungs of the planet") could die.
That's not just bad news for the plants and animals; it would also mean more flooded homes, stronger hurricanes, more intense wildfires, and dirtier air.
Their suggestions involve major shifts in the ways we grow food and distribute money to cut down our greenhouse-gas emissions.
"The Earth's life-supporting systems are worth it," the authors wrote.
A study of 1.2 million US adults published in The Lancet Psychiatry reported, unsurprisingly, that people who exercised regularly tended to feel better.
In the study, researchers looked at national surveys from the Centres for Disease Control and found that people who said they exercised consistently reported fewer days when their mental health was "not good."
It didn't matter whether people were participating in team sports, going to the gym solo, cycling outdoors, going for a walk, or even doing some housework, the study authors found. Any type of exercise worked as long as people got moving three to five times per week, the researchers said.
"This study reiterates the broad range of health benefits for exercising, no matter your age, race, gender, income, or physical health status," senior study author Adam Chekroud, a psychiatry researcher at Yale University in New Haven, told Reuters. "Every little bit helps - as low as 30 minutes - and every exercise group including walking was associated with lower mental health burden."
Researchers analysed the diets of people in more than 20 countries, then compared that information to how long people lived.
They found that, in general, people who consumed a moderate amount of carbohydrates (about half a person's daily calories) and stuck to whole grains and unprocessed foods fared best. The results were published in The Lancet.
Lead researcher Sara Seidelmann, a cardiologist and nutrition researcher at Brigham and Women's Hospital in Boston, told Business Insider that a diet "rich in plant based whole foods such as vegetables, whole grains, legumes, and nuts is associated with healthy ageing."
Like the study on drinking, this research was a meta-analysis, which means we can't say for sure that the food is responsible for the longer lives. It may just be that people who consume roughly 50% of their daily calories from carbohydrates tend to live longer for other reasons like genetics or wealth that weren't measured by this study.
More randomised controlled trials would help us to know for sure.
The Ocean Cleanup Foundation visited the patch in 2015 with 18 vessels and used trawl nets to estimate how much plastic was in the area, which is more than 1.6 million square km wide. They reported the results of that work this spring.
The Great Pacific Garbage Patch isn't the only place where trash gets trapped in the ocean - there are at least four others like it scattered around the world. They're floating reminders of the impact that our plastic use has on oceans and sea life.
For the study, researchers looked at cancer patients with early-stage breast, prostate, lung, or colorectal cancers. Some patients chose to use "complementary medicine," which can include herbs, supplements, acupuncture, special diets, and other treatments that haven't been clinically proven. Such treatments can help ease symptoms, but they haven't been shown to cure cancers.
The researchers found that patients who used the complementary treatments were more likely to either delay or refuse conventional treatments like chemotherapy, surgery, radiation, or hormone therapy. Those delays and refusals, in turn, led to higher death rates.
"Unfortunately, there is a great deal of confusion about the role of complementary therapies," lead study author doctor Skyler Johnson from Yale School of Medicine said in a release when the study was published in JAMA Oncology. "Although they may be used to support patients experiencing symptoms from cancer treatment, it looks as though they are either being marketed or understood to be effective cancer treatments."
A study published in April in the journal Nature revealed that one third of the coral in the Great Barrier Reef was killed as a result of one blistering 2016 heat wave.
Other reefs around the world are also perishing quickly: some estimates suggest we've lost half of the world's reefs in the past 30 years. Roughly a quarter of the world's fish species thrive in coral reefs at some point in their life-cycles. Reefs protect our own houses, too, since they buffer the shore from storms, floods, and erosion.
But that's not all.
"You like to breathe?" Michael Crosby, a marine scientist and the president of Mote Laboratory and Aquarium, asked Business Insider earlier this year. "Estimates are that up to 80% of the oxygen you are breathing in right now comes from the ocean. It doesn't come from the land. In order for you to continue to breathe, you have to have a healthy ocean."
In May, scientists calculated how much all life on Earth weighs. Their findings, published in the Proceedings of the National Academy of Sciences, revealed that humans are a puny part of the planet: 0.01% of the global biomass.
Plants dominate across the Earth, weighing about 7,500 times more than people. But despite our own paltry weigh-in, humans' effects on the planet extend far beyond our own kind.
"A worldwide census of the total number of trees, as well as a comparison of actual and potential plant biomass, has suggested that the total plant biomass (and, by proxy, the total biomass on Earth) has declined approximately twofold relative to its value before the start of human civilisation," the study authors wrote.
In addition to killing off half of the world's plants, "humanity has caused the loss of 83% of all wild mammals," The Guardian reported when the study was released.
It's a reminder that the consequences of human activity now threaten most life on Earth.
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