Scientists have long considered polar ice to be an extreme environment; a sterile place within which nothing can survive.
But new evidence shows that there are living bacteria in Arctic and Antarctic ice and snow, and that fact has never been taken into account when looking at ice-core gas samples to assess the Earth’s levels of climate change. And that may have thrown off our predictions of planetary warming—in a very negative way.
It could be that our CO2 increase is actually even bigger than we previously thought and that humans have had a more extreme effect on the Earth’s atmosphere than past ice-core studies have suggested.
Climate change is more rapid than we thought
Since the 1950s, ice-core samples have been used to compare prehistoric levels of CO2 in the atmosphere with the current levels in our postindustrial age. Gases (pockets of air) captured and sealed in snow as it compresses into ice provide researchers with snapshots of the Earth’s atmosphere going back hundreds of thousands of years.
Ice-core analysis has traditionally relied on the assumption that there is limited biological activity altering the environment in the snow during its transition into ice. But this new research, authored by K. R. Redeker, J. P. J. Chong, A. Aguion, A. Hodson and D. A. Pearce, published in the Journal of The Royal Society Interface and titled Microbial metabolism directly affects trace gases in (sub) polar snowpacks, reveals that the composition of these small samples of gas trapped in the ice may have been affected by bacteria that remain active in snow while it is being compacted into ice—a process that can last decades and which has never been factored in when looking at ice-core gas samples.
To conduct the study, researchers looked at two kinds of snow: 1) snow in its natural state and 2) snow in other areas they sterilized by using ultraviolet lamps. Cutting-edge techniques enabled the team to detect the presence of gases even at part-per-trillion levels, one million times less concentrated than atmospheric CO2 concentrations.
When they compared the results, the scientists found that unexpected levels of methyl iodide—a gas known to be produced by marine bacteria—were found in the untouched snow.
Respiration by these bacteria may have slightly increased levels of CO2 in pockets of air trapped within polar ice caps; meaning that before human activity, CO2 levels were likely even lower than reported earlier. And that means that climate change is happening even more rapidly than we thought.
Sea-level rise is faster than we estimated
Discovering these bacteria may not be the only sign that Earth is warming far more quickly than once believed. In Greenland, mysterious microbes are turning the polar ice pink—and speeding up melt.
One summer a few years ago, according to an online article in National Geographic, a researcher working on the southwestern margins of the Greenland ice sheet noticed a mauve shade on the melting ice surface around him. While at first he assumed the color was the result of his wearing a pair of pink-colored cycling glasses instead of his customary glacier goggles, he gradually realized that there were microbes growing in the ice. When an algae specialist took a look at the ice under a microscope, she confirmed the researcher’s suspicion: just beneath the ice surface lived red algae that was turning the ice pinkish.
In order for the red algae to form blooms visible to the eye and to increase the melting of the snow and ice by darkening the ice surface (thereby lowering its albedo, or its ability to reflect the sunlight back into space, resulting in more light absorbed and more melting), it just needs the right conditions, which at a minimum involve basic nutrients and melting. As the climate gets warmer, the availability of liquid water from snow and ice becomes higher, favoring the growth of the algae.
And, as with the newly discovered bacteria in polar ice, experts had not been accounting for the effect of the red algae blooms in their projections of global sea-level rise. The possibility, for instance, was not included in the estimates for sea-level rise published by the United Nation’s Intergovernmental Panel on Climate Change in its latest report in 2013.
The Greenland ice sheet is the biggest in the Northern Hemisphere. Each year, it loses 270 billion tons of ice as the planet heats up, adding a fraction of an inch to global sea levels. But the amount of melting is speeding up year by year; and if the entire ice sheet melted, it would add 20 feet to sea levels.
Scientists worry that in the not-too-distant future, the effects of the liquefying Greenland ice sheet will be felt in coastal areas, such as Miami, New York and Shanghai, as well as in low-lying areas, such as Bangladesh and Indonesia.
Having to find another home is closer than we believe
Environmentalists often remind us that “there is no Planet B.” But the fact that metabolically active bacteria have been found in the most pristine ice and snow could be perceived as a ray of hope: it’s a sign that life can proliferate in places where you wouldn’t expect it to exist—even in cold, remote, nutrient-poor spots, such as the universe’s frozen planets, which were once deemed by scientists as incapable of supporting life.
Perhaps we should start looking for that new planet to call home.
Here’s to finding your true places and natural habitats,