For the first time, researchers studying changes in the Arctic have linked individual carbon footprints to the rapid loss of the region’s sea ice.
According to a study, published in the journal Science, report that for every metric ton of carbon dioxide added to earth’s atmosphere, the Arctic loses 3 sq. m. of sea ice. This means that, on average, each American is annually responsible for the disappearance of roughly 538 sq. ft. of sea ice. Researchers from the Max Planck Institute for Meteorology led by Dirk Notz took samples of the Arctic sea ice at Spitzbergen and examined them to understand the development of sea ice in the region. After comparing corresponding model calculations with data from satellite measurements, the researchers discovered a linear relationship between carbon dioxide emissions and the area of Arctic summer ice. Moreover, the researchers found that earlier climate models have underestimated the loss of Arctic sea ice.
“For us, this is really the first time that we do have an intuitive understanding of how our individual actions really contribute to global warming,” said lead author Dirk Notz, a climate scientist at the Max Planck Institute for Meteorology in Hamburg, Germany. “So far, when we talked about global warming, it was always these very big numbers, like billions of tons of carbon dioxide — or very small numbers like 0.1 degree of temperature change or something. But now suddenly, with this three-square-meter loss per ton of CO2, it gives a very, very concrete and intuitive understanding of how we all cause Arctic sea ice to melt.”
The melting Arctic sea ice is one of the biggest indicators of climate change. Over the past four decades, the summer sea ice has shrunk by more than half. In September, satellite observations have revealed that the Arctic sea ice was at its second lowest ever recorded, at 4.169 million sq. kms. The lowest was in 2012 when Arctic sea ice was only 3.41 million sq. kms.
The new measurement provides a sense of how much damage an individual’s personal lifestyle could cause to the Arctic sea ice. For instance, the average American emits about 16 metric tons of carbon dioxide a year, according to data from the World Bank. This follows that the average American is melting about 50 square meters of Arctic sea ice per year.
This is an alarming situation, not only for species dependent on seasonal ice for survival, but also for increased chances of devastating new weather patterns over much of the world.
Arctic sea ice, the vast sheath of frozen seawater floating on the Arctic Ocean and its neighboring seas, has been hit with a double whammy over the past decades: as its extent shrunk, the oldest and thickest ice has either thinned or melted away, leaving the sea ice cap more vulnerable to the warming ocean and atmosphere.
“What we’ve seen over the years is that the older ice is disappearing,” said Walt Meier, a sea ice researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This older, thicker ice is like the bulwark of sea ice: a warm summer will melt all the young, thin ice away but it can’t completely get rid of the older ice. But this older ice is becoming weaker because there’s less of it and the remaining old ice is more broken up and thinner, so that bulwark is not as good as it used to be.”
“So far, climate change has often felt like a rather abstract notion. Our results allow us to overcome this perception,” Julienne Stroeve, co-author of the study, said in a statement. “It seems that it’s not primarily the sea ice models that are responsible for the mismatch. The ice just melts too slowly in the models because their Arctic warming is too weak.”
“We hope that this study will allow people to more intuitively grasp the mere fact that Arctic sea ice does not disappear because of some large-scale, anonymous action,” said Notz, “but simply because of our little day-to-day activities.”