Ice levels in west Antarctica are cyclical, Balgord writes. (Frederique Olivier / AFP/Getty Images)
The best and worst of journalism is surfacing on the heels of the administration’s National Climate Assessment report, created in support of EPA’s soon-to-be-released CO2 regulations.
But catastrophic melting of polar icecaps and abruptly rising sea level — first predicted in 1922, prominently flagged in the NSA document — show no signs of materializing. News accounts misreport a European Space Agency study alleged to have discovered doubling of melt rate of the West Antarctic ice sheet, re-igniting warnings of imminent collapse
Reduction of Antarctica’s glaciers has proceeded since the end of the last ice age. Considerably more time, even millennia, would be required to raise ocean levels by 12-13 feet mentioned in various news accounts (assuming constant 7- inches-per-century rise).
Intervening periods of cooling could interrupt or reverse the process as has happened in the past. Recent reductions in sun-spot activity signal the arrival of the current Sun Cycle 24. Scarce sunspots foretell a cooling much sooner than climate alarmists may realize.
Carbon dioxide added to the atmosphere by man’s activities since 1950 (post-World War II industrial expansion) has contributed little to global-scale warming compared with natural processes that dominate climate. Increasing CO2 and slowly melting icecaps do not signal imminent demise of the West Antarctic ice sheet, as the New York Times recently intimated.
Statements suggesting anthropogenic CO2 triggers high-velocity circumpolar winds over the Southern Ocean (driving “warm” currents) are speculative for a region already notorious for high winds and treacherous seas. The New York Times expects that the “imminent collapse” might be delayed into the next millennium, should warming resume. But patterns of past warming followed by cooling are very common in the Pleistocene record, interpreted from ice-core and ocean-sediment core data recovered at widely separated locations around the planet.
Recent satellite observations suggest ice mass over much of the interior of the Antarctic continent is increasing along with expanding sea ice. Observations are consistent with the idea that a warmer (comparatively) Southern Ocean generates greater amounts of snowfall over the continent, helping to replenish glacial ice.
Narrow ice-shelves, extending from the western margin of the ice sheet into the Amundsen Sea, are fed by two outlet glaciers. “Thwaites” and the “Pine Island” glaciers discharge through gaps into the embayment. They drain glacial fields from the smaller northern portion of the WA ice sheet bounded on the east by the Trans-Antarctic Mountains. The much larger — and stable — East Antarctic ice sheet extends beyond these mountains.
The “grounded” WA ice sheet lies on a depressed platform of bedrock that would be submerged absent the ice. But the weight of more than a mile of ice ensures continuous grounding of the main body, effectively blocking entry of sea water beneath the ice in event of “collapse” (rapid calving) at the edge. A succession of potential grounding lines (represented by submarine ridges) lies in the path to block intruding sea-water.
The “unstoppable” melting of the West Antarctic ice sheet is thus wide open for discussion. Is volcanic activity in the immediate area playing a role? Clearly, the entity existed during and between previous continental glacial periods and the latest that ended 10,000 years ago. The New York Times notes a small ice shelf along the eastern side of the Antarctic Peninsula melted about 6,000 years ago, then reconstituted. The smallest of several nearby shelves broke into icebergs in 2002, causing great consternation.
Pessimism over continued melting of the WA ice sheet may prove unwarranted. Global-scale cooling followed each past period of Holocene warming: the Dark Ages Minimum after the Roman Optimum; the Little Ice Age after the Medieval Optimum. The British Antarctic Survey reports major periods of partial melting, then re-establishment of polar ice sheets on several occasions from about 8,000 years BP forward.
Efforts by NASA/JPL and others to model regional climate by statistical or mathematical methods have disappointed adherents. Global climate models, in aggregate costing more than $1 billion, all failed to anticipate an ongoing pause in warming since 1996-97. They also fail a priori to replicate a known temperature record beginning in 1950. In climate science language, the models being used to formulate federal policy lack “skill.”
Failures spring from inadequate understanding of the physical processes taking place in dynamic systems on and above the Earth’s surface. It is the processes, not the models, which determine our weather in the near-term and climate change over periods of decades and longer. Model simulations alone, no matter how sophisticated, are an unreliable basis to formulate energy policy.
William Balgord, geochemist and writer, heads Environmental & Resources Technology Inc., in Middleton, Wis.