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Amongst all the drama of the fiscal cliff, the story that should have gotten front page space this week is that the Antarctic is melting much faster than previously thought. In my post ‘Burning the Candle at Both Ends‘, the recent finding that the Antarctic was indeed losing ice came as a revelation to many and dispelled the popular belief amongst the global warming ‘denialist’ crowd that the South Pole ice sheet was increasing. The situation has now gotten more dire:

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What are the ramification of this? We’ve released another ticking methane time bomb and opened up one more pandora’s box of known and unknown feedback loops:

…Half the West Antarctic ice sheet and a quarter of the East Antarctic sheet lie on pre-glacial sedimentary basins containing around 21,000bn tonnes of carbon, said the scientists, writing in the journal Nature.

British co-author Prof Jemma Wadham, from the University of Bristol, said: “This is an immense amount of organic carbon, more than 10 times the size of carbon stocks in northern permafrost regions.

“Our laboratory experiments tell us that these sub-ice environments are also biologically active, meaning that this organic carbon is probably being metabolised into carbon dioxide and methane gas by microbes.”

The amount of frozen and free methane gas beneath the ice sheets could amount to 4bn tonnes, the researchers estimate…

guardian.co.uk, Wednesday 29 August 2012 13.00 EDT

And what will happen to coastal communities? If one were to perform a linear projection of sea level rise from recent records, then you would get the following results:

…Currently, sea level is rising at the rate of 3 mm each year. Given 1″ = 25 mm, this means by the end of the century a rise of 87 (yrs) x  3 mm / yr. = 261 mm or (261 mm/ 25 mm/in) = 10.44 inches – enough to wash away roughly one third of S. Florida and most of the sea level areas of the Atlantic coast…

But this year’s shocking display of rapid ice melt in the Arctic and Greenland, in addition to new findings of the Antarctic warming at twice the rate as was previously thought, should be enough to tell you that future trends involving systemic changes in the environment will most certainly be exponential in nature, not linear. In other words, such effects as sea level rise will be orders of magnitude greater than what has been predicted:

…IPCC (2007) suggested a most likely sea level rise of a few tens of centimeters by 2100. Several subsequent papers suggest that sea level rise of ~1 meter is likely by 2100. However, those studies, one way or another, include linearity assumptions, so 1 meter can certainly not be taken as an upper limit on sea level rise…

…Hansen (2005) argues that, if business-as-usual increase of greenhouse gases continue throughout this century, the climate forcing will be so large that non-linear ice sheet disintegration should be expected and multi- meter sea level rise not only possible but likely. Hansen (2007) suggests that the position reflected in IPCC documents may be influenced by a “scientific reticence”…

…Perceived authority in the case of ice sheets stems from ice sheet models used to simulate paleoclimate sea level change. However, paleoclimate ice sheet changes were initiated by weak climate forcings changing slowly over thousands of years, not by a forcing as large or rapid as human-made forcing this century. Moreover, in a paper submitted for publication (Hansen et al., 2013) we present evidence that even paleoclimate data do not support the degree of lethargy and hysteresis that exists in such ice sheet models…

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…The increasing Greenland mass loss in Fig. 1 can be fit just as well by exponentially increasing annual mass loss, a behavior that Hansen (2005, 2007) argues could occur because of multiple amplifying feedbacks as an ice sheet begins to disintegrate. A 10-year doubling time would lead to 1 meter sea level rise by 2067 and 5 meters by 2090. The dates are 2045 and 2057 for 5-year doubling time and 2055 and 2071 for a 7-year doubling time.

However, exponential ice loss, if it occurs, would encounter negative (diminishing) feedbacks. Our simulations (Hansen and Sato, 2012) suggest that a strong negative feedback kicks in when sea level rise reaches meter-scale, as the ice-melt has a large cooling and freshening effect on the regional ocean. Such a slowdown in the rate of sea level rise would be little consolation to humanity, however, as the high latitude cooling would increase latitudinal temperature gradients, thus driving powerful cyclonic storms (Hansen, 2009), and coastlines would be continually moving landward for centuries.

West Antarctic ice is probably more vulnerable to rapid disintegration than Greenland ice, because the West Antarctic ice sheet rests mainly on bedrock below sea level (Hughes, 1972). The principal mechanism for mass loss from West Antarctica is warming of the ocean, melting of West Antarctic ice shelves, and thus increased flux from the ice sheet to the ocean.

The several analysis methods compared by Shepherd et al. (2012) concur that the West Antarctic ice sheet mass imbalance has grown since 2005 from an annual mass loss of 0-100 Gt ice to a recent annual mass loss of 100-200 Gt ice (Fig. 4 of Shepherd et al.)…

There are roughly seven billion humans on Earth at this time, all of whom have a death sentence hanging over their head via anthropomorphic climate change. Perhaps this partly explains the recent popularity of zombies and the ‘walking dead’ in our culture. Forthright thoughts on this subject from a scientist commenting at the Arctic Sea Ice Blog:

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The first signs have appeared of what will be a mass culling of the human population by way of famine in the decades to come:

…According to the Food and Agriculture Organisation in Rome, global wheat production is expected to fall 5.2% in 2012 and yields from many other crops grown to feed animals could be 10% down on last year.

“Populations are growing but production is not keeping up with consumption. Prices for wheat have already risen 25% in 2012, maize 13% and dairy prices rose 7% just last month. Food reserves, held to provide a buffer against rising prices, are at a critical low level.  It means that food supplies are tight across the board and there is very little room for unexpected events,” said Abdolreza Abbassian, a senior economist with the FAO…

My youngest son, who is eight years old, shocked me last week with a certain question. I don’t talk about the subject matter of this blog to him for obvious reasons. He asked me whether in the future the world would become a sort of technological paradise or a destroyed planet. I couldn’t answer his question. I didn’t even want to try.