Goodbye Sea Ice, Hello La La Land
Photograph: AMSR-E/Aqua/NASA
Civilization is experienced at many scales, from the individual to the global. In between these end points are families and friends, neighborhoods, the workplace, the various levels of government, etc. And whether we are aware of it or not, our every word and action resonates at all these levels and scales.
Two related articles in the November 4th Science journal speak to our participation—individually and globally—in the melting of Arctic sea ice.[i] Science is considered, along with the British journal Nature, as one of the world’s most prestigious science journals. When they publish a paper, it’s worth at least considering it.
Here’s what they found: for whatever reason, no one had yet done a study of the relationship between global carbon emissions and the loss of sea ice in the Arctic. There have been plenty of mathematical models linking carbon emissions to diminishing sea ice, but there had been no analysis based on actual observations. So, two scientists—Dirk Notz and Julienne Stroeve—compared the recorded areas of Arctic summer sea ice to the carbon dioxide emissions that have been accumulating in the atmosphere. And… drum roll… the loss of summer sea ice has been tracking perfectly with global CO2 emissions. Okay, no big surprise there, perhaps. Still, two things do stand out: One, it’s not “just” theoretical, it’s based on decades of observation. Two, given the complex nature of the Earth in general and the Arctic specifically, it’s particularly alarming when two detrimental phenomena correlate so simply.
Why does the Arctic summer sea ice matter? Two fundamental reasons come to mind. One is that many large mammals—including polar bears, walruses, and a number of seal species—exist in a delicate balance with the seasonal fluctuations of the sea ice.
(AP Photograph/U.S. Fish and Wildlife Service) "35,000 walruses have mobbed the Alaskan coast--because there's no sea ice left to rest on."
Two, sea ice is part of the Earth’s refrigeration system: the less ice there is, the more sunlight the now exposed water absorbs. This is one of those many positive feedback mechanisms that scientists truly fear; “positive” here meaning “in the same direction,” not “good.” The less ice there is covering the Earth, the less sunlight gets reflected back into space. Therefore, the more sunlight the planet absorbs, the warmer the planet becomes, and the more ice melts… which leads to more absorption of sunlight, etc.
Now, let’s examine the consequences of our individual behaviors on the Arctic sea ice. According to Notz and Stroeve, the average American household of four is responsible for about 200 square meters of additional Arctic summer sea ice loss every year. That’s about 2,150 square feet less sea ice than the previous year. Since most adults with two children are too busy to read esoteric websites, and since most of us are not part of a household of four, but rather tend to think of ourselves as independent agents, let’s look at these numbers in terms of one person only. Individually, each and every American is responsible for about 540 square feet of cumulative Arctic sea ice loss, each and every summer of each and every year. In 30 years, that comes out to 16,000 square feet. That’s about a third of a football field. Again, per American. Some actions melt more ice than others. Every time we fly from New York City to London, for instance, or any similar six-hour flight, we will melt one square meter (or almost 11 square feet) of Arctic ice.[ii] Hello Big Ben, goodbye polar bear.
It will not be of any surprise that Americans are responsible for more ice melt than just about any other group in the world; ten times that of an Indian, for instance.
When we telescope our personal melting square of sea ice to the global scale and then project our behaviors into the future, we will discover that the Arctic summers will be essentially ice-free before mid-century. Some simple math, maps, and a graph will do the work for us.
The graph below shows us that carbon dioxide emissions have been rising steeply in the past decades. In 2016, Civilization has pumped about 35 billion tons of carbon dioxide into the atmosphere. That was a little more than the year previous, and likely a little less than will be emitted the following year.
For perspective, one metric ton of carbon dioxide would fill 556 cubic meters of space, almost enough to completely inflate a small hot air balloon.[iii] The most common hot air balloon carries three to five people and is about 2,800 cubic meters in volume. That balloon could hold exactly five tons of carbon dioxide. If carbon dioxide molecules became magically visible and collected into hot air balloon masses, we would witness 7 billion such balloons floating up into the atmosphere every year.[iv] The Earth’s surface area is 197 million square miles.[v] So, we add about 36 of these magically floating CO2 blobs over every square mile of the Earth, land and oceans… every year.
A person extrapolating our behavior into the future could reasonably presume that we will be increasing our annual output of greenhouse gases in the coming decades. A problem with extrapolations, of course, is that they ignore complexities, known and unknown.[vi] For example, if nations honor their pledges made during the 2016 Paris Agreement, we may actually slow the rate of increase, and eventually even decrease carbon emissions. Big if. Donald Trump has already promised to “cancel” the U.S. pledges.[vii] Another complication: the annual 35 billion ton estimate is of CO2 gas only, from fossil fuels mostly. We emit other greenhouse gases—methane (CH4) and nitrous oxide (N2O) among them—that when accounted for, edge our CO2 equivalent emissions closer to 55 billion tons per year.[viii] That would be enough to float 11 billion of our magical carbon balloons every year; 56 annual carbon dioxide hot air balloons per square mile; one for every acre of Earth’s surface in just eleven-and-half years.[ix] Now imagine that in our La La Land each of these floating blobs absorbed enough sunlight to warm its little acre by 3 ˚F over normal weather conditions. Randomly warm. Winds would concentrate heat here and there, so that sometimes your acre is normal, sometimes it’s twenty degrees hotter. If a heat wave hits you in July or August, you would pity the farmer and anyone without air-conditioning.
Let us now go to another La La Land, where we will be outrageously optimistic for a moment. Let us assume that Civilization somehow freezes its CO2 emissions to 2016 levels for the foreseeable future and completely eliminates the warming effect of all the other gases. By releasing only the 35 billion tons of carbon dioxide annually, another 1000 billion tons would accumulate in 29 years. That would be in the year 2045. A thousand billion is a trillion. According to the relationship we observed above, a trillion tons will lead to 3 million square kilometers of Arctic de-icing, which would lead to an “essentially ice free” Arctic summer, according to our scientists. And that’s the optimistic scenario.
A trillion tons was chosen for a second reason, as well. As it turns out, scientists have calculated that the additional 1000 billion tons of carbon dioxide will raise global atmospheric temperatures by about 1.3˚C, for a total of 2˚C (3.6 ˚F) since the beginning of our industrial revolution binge.[x] Why is that number important? Because scientific consensus suggests that the energy added to the atmosphere with a two-degree rise will likely take us into atmospheric conditions not experienced since the Eemian interglacial some 125,000 years ago and will create conditions for which we cannot yet reliably forecast.[xi]
Atmospheric conditions might well reset to some new and as yet unknown global-scale dynamic equilibrium. The Paris Climate agreement was hoping to delay this 2˚C threshold until 2100. At present emission rates, we will be there sometime between 2030 and 2045, more than a half-century early.
On the horizontal axis is the CO2 emitted in billions of tons (Gt). The vertical axis projects the likelihood of remaining under the 2˚C threshold. Note that 1000 billion tons holds an 80% probability. By 1500 billion tons the probabilities are getting to be 50-50.
And that will affect just about every living thing on the planet, especially our species. The global climate has been rather stable in the past ten thousand years and favorable to agriculture and therefore to Civilization. Farming produced so much food that it fed a human population explosion, as well as an irruption of livestock and a few domesticated plants such as rice, wheat, and corn. Humanity has appropriated about 40% of the biosphere's yearly photosynthesis. We have turned the planet’s verdant lands into a vast food trough for our species. Any atmospheric and climate shifts are unlikely to work in our favor. Indeed, scientists are certain that climate change will negatively impact food security in the coming decades, particularly in regions that are densely populated and already experiencing hunger.[xii] Furthermore, the droughts, heat waves, and crop losses that are projected for this century will likely impact the viability of many African and west and south Asian states. A number of them are already unstable. The debacle unfolding in Syria, for instance, has its roots in that region’s worst drought in 900 years.[xiii] And the climate refugees that will be pouring out of the worst affected regions will strain just about everybody else.
We are blithely heading for unchartered waters while the scientists yell at us from the crow’s nest, trying to wake us up. But what is a person to do? We’ll look at radical solutions in the coming weeks.
REFERENCES
[i] Cornwall, W. (2016) Sea Ice Shrinks in Step with Carbon Emissions. Science, v. 354, pp. 533-534.
Notz, D. and Stroeve, J. (2016) Observed Arctic Sea-Ice Loss Directly Follows CO2 Emission. Science, v. 354, pp.
[ii] This is according to Cornwall, W. (2016) Sea Ice Shrinks in Step with Carbon Emissions. Science, v. 354, pp. 533-534. Carbon dioxide emitted from plane flights calculated by http://blueskymodel.org/air-mile.
[iii] From the International Carbon Bank and Exchange at http://www.icbe.com/carbondatabase/co2volumecalculation.asp:
Volume calculation of one ton CO2
One ton = 1000kg
One cubic meter = 1000liters
One mole CO2 = 44.0g (CO2 = 12.0g + 32.0g = 44.0g)
One ton contains 22730 moles of CO2 (1,000,000g / 44.0g/mole)
One mole is 24.47L (Boyle's law at 25°C and 1 atmosphere pressure)
Volume of one ton CO2 = 22730moles × 24.47L/mole = 556200L = 556.2m³
One ton of CO2 occupies 556.2m³ of volume.
iv] 35 billion tons ÷ 5 tons/balloon = 7 billon balloons
[v] That is, the Earth’s surface—land and oceans—would be almost perfectly covered with 197 million squares, each having the dimension of 1 mile x 1 mile.
[vi] For instance, Tollefson, J. (2015) Is the 2 ˚C World a Fantasy? Nature, v. 527, pp. 436-438. Accessed December 10, 2016 at http://www.nature.com/news/is-the-2-c-world-a-fantasy-1.18868
[vii] http://www.bbc.com/news/election-us-2016-36401174
[viii] https://insideclimatenews.org/content/charting-paris-climate-pledges
http://www.nature.com/nclimate/journal/v3/n5/fig_tab/nclimate1793_F1.html / For this one, the first graph shows emissions in carbon equivalents. To get CO2 equivalents, one can use this proportionality:
44 (atomic mass of CO2)/12 (atomic mass of C) = (x tons of CO2 equivalent)/9.5 tons of carbon
[ix] There are 640 acres to a square mile.
[x] Meinshausen, M., Meinshausen, N., Hare, W., et al. (2009) Greenhouse Gas ,Emission Targets for Limiting Global warming to 2 ˚C. Nature, v. 458, Pp. 1158-1162.
Rogelj, J., Schaeffer, M. et al. (2013) Differences between Carbon Budgets Unravelled. Nature Climate Change, v. 6, pp. 245-252.
[xi] http://www.slate.com/blogs/future_tense/2016/03/01/february_2016_s_shocking_global_warming_temperature_record.html
http://www.cnn.com/2015/04/21/opinions/sutter-climate-two-degrees/
[xii] Cline, W. R. (2007) Global warming and agriculture: Estimates by country. Washington, DC: Peterson Institute.
Parry, M., Arnell, N., McMichael, T., Nicholls, R., Martens, P., Kovats, S., et al. (2001) Millions at risk: Defining critical climate change threats and targets. Global Environmental Change, 11, 181–183. doi: 10.1016/S0959-3780(01)00011-5.
Rosenzweig, C., & Parry, M. L. (1994). Potential impact of climate change on world food supply. Nature, 367, 133–138. doi:10.1038/367133a0.
Schade, C., and Pimentel, D. (2010) Population Crash: Prospects for Famine in the Twenty-First Century. Environment, Development and Sustainability, v. 12, pp. 245-262.
[xiii] Friedman, T. (2013, May 18) Without Water, Revolution. New York Times. Accessed December 10, 2016 at http://www.nytimes.com/2013/05/19/opinion/sunday/friedman-without-water-revolution.html.
NASA (2016) NASA Finds Drought in Eastern Mediterannean Worst of Past 900 Years. Accessed December 9, 2016 at https://www.nasa.gov/feature/goddard/2016/nasa-finds-drought-in-eastern-mediterranean-worst-of-past-900-years/
