How much of the Arctic region’s sea ice are you responsible for melting? Thanks to newly-published scientific research, the answer can now be found.
Professor Julienne Stroeve works at both University College London (UCL) and the Boulder, Colorado-based National Snow and Ice Data Centre, while Dr Dirk Notz leads the MPI-M (Max Planck Institute for Meteorology) group ‘Sea Ice in the Earth System.’ These two climate scientists have carried out groundbreaking combined environmental research studies. Together, they’ve worked out the impact of individual CO2 emissions on summer sea ice volumes which are at their lowest each September.
The pair discovered a direct correlation. That’s since allowed them to describe the climate change concept much more personally than the “rather abstract notion” it’s typically become. Details of the approach they took appear in a paper just published by ‘Science’.
Arctic Sea Ice Melts
Arctic sea ice is subject to seasonal fluctuations in any case but peak and base levels are now in constant annual decline. Many scientists attribute that drop to climate change arising from industrial activity, with CO2 emissions raising both atmospheric and oceanic temperatures. Previous climate change/ice loss studies have tended to be overcomplicated: not so in the case of Stroeve’s and Notz’ work, which drew on statistics, observations and a reported 30 computer models.
"So far, climate change has often felt like a rather abstract notion”, Stroeve comments. "Our results allow us to overcome this perception.”
Emissions And Ice Loss
The average United States resident generates 16.39 metric tons of CO2 emissions each year – or at least he/she did in 2013 – and, every time one metric ton of carbon dioxide is emitted, three square metres of Arctic sea ice disappears. That makes each person living in the US indirectly responsible for melting approximately 50 square metres of Arctic sea ice each year.
To put those figures into context, a typical ‘family’ car, covering 2,500 miles of highway, emits around one metric ton of CO2 for each person inside, so there’s one three square metre ice ‘patch’ gone. Each of those people, were they to take a return flight from New York to London, would melt another patch and that’s, according to Stroeve’s and Notz’ findings, really all it takes.
“It’s very simple”, Stroeve explains. “Those emissions from our tailpipes and our coal-fired power plants are all going into the atmosphere. It just increases the warming at the surface. So, the ice is going to respond to that. The only way it can do that is to move further north.”
“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”, Notz adds. "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-metre loss per ton of CO2, it gives a very, very concrete and intuitive understanding of how we all cause Arctic sea ice to melt."
Based on current climate models, actual Arctic sea ice loss levels are probably understated. On that basis, the two researchers think even deeper CO2 emissions cuts are needed than the internationally-agreed two degrees aim if the Arctic’s now to retain any ice throughout the summer months.
‘Only for the much lower emissions that would allow one to keep global warming below 1.5 °C, as called for by the Paris agreement, Arctic summer sea ice has a realistic chance of long-term survival, the study concludes’, the Max Planck Institute’s 3 November news release quotes in closing.