These ‘giant’ viruses could be a solution to melting Arctic ice

A lot of seemingly outlandish ideas have been floated as ways to cool the rapidly warming planet in recent years. Cloud brightening ? That might work. Installing 10 million pumps in the Arctic to help make more sea ice? Seems like a stretch. Putting giant mirrors into space to reflect sunlight? Probably very expensive, but sure. And now we can add another to the list: giant viruses. 



Researchers from the Department of Environmental Science at Aarhus University in Denmark say they have for the first time discovered signs of large viruses living in the snow and ice on the Greenland ice sheet. These “giant” viruses really are huge, at least relatively. Compared to their average-size cousins, they can grow to be up to 1,500 times larger. But it’s not their size that makes these organisms potentially important to climate scientists—it’s what they like to infect. 



Greenland’s ice sheet is the largest in the Northern Hemisphere, and it is melting. Recent data suggests it is losing 30 million tonnes of ice an hour. If it melted entirely, global sea levels would rise by more than 20 feet. Contributing to the melt rate is a type of algae that grows on the Arctic sea ice and turns the surface a dark red or black in the spring and summer.



Darker surfaces absorb more heat, thus accelerating the melting. Here’s where the giant viruses come in: The researchers suspect that they infect and destroy this algae. And if giant viruses can be deployed strategically to attack glacier algae, perhaps they could help cool things down. 



There are some caveats to consider. It’s not 100% certain that these giant viruses do infect algae, only that their gene signatures were found in samples of ice displaying the inky hues of a microalgae bloom. Previous research has confirmed that giant viruses found in the ocean do indeed infect and kill algae there. But beyond that, not much is known about how giant viruses behave on the ice sheet, or how they could be harnessed to control the algae blooms.



Photo: Laura Perini/Aarhus University]



“How specific they are and how efficient it would be, we do not know yet,” said Laura Perini, one of the researchers, and coauthor of the resulting study published in the journal Microbiome . She and her team are continuing their investigations on the viruses and have further research coming out soon. 



There’s also a lot that remains unknown about the algae blooms themselves. We do know that they’re sometimes big enough to be seen from space during the summertime, and can increase surface ice melt by roughly 10% . But what makes them thrive? And what unintended consequences could there be of tweaking their ecosystem?



This last question is one with which all projects that seek to tinker with the Earth’s climate must grapple. Working with viruses and algae might seem slightly more “natural” than launching space mirrors and brightening the clouds, but every action has a knock-on effect. Still, as our global greenhouse gas emissions continue to rise and the planet’s temperature moves into scary and uncharted territory, scientists are glancing nervously at proposals for cooling the planet that once seemed entirely unthinkable.