Professor Jeff Obbard delivered a seminar at Sun Yat-Sen University in Guangzhou, China on 27 June 2018 entitled: The Earth’s Energy Imbalance: Implications for Ice Dynamics & Climate Tipping Points.

The seminar was based upon recent data published in the journal Nature in June by the Ice Sheet Mass Balance Inter-comparison (IMBIE) team. Satellites monitoring the state of the Antarctic Continent indicate about 160 billion tons a year are now being lost to the ocean because of melting.

Prof Obbard (right) with host Professor Jason Cohen at the School of Atmospheric Sciences, Sun Yat-Sen University, Guangzhou, Cina on 27 June 2018.

Ice losses are occurring predominantly in the West of the Antarctic, where warm waters are getting under and melting the fronts of glaciers that terminate in the ocean. In West Antarctica, which is dominated by marine-terminating glaciers, the assessed losses have climbed from 53 billion to 159 billion tons per year over the full period from 1992 to 2017. This is pushing up global sea levels by 0.6mm annually – a three-fold increase since 2012 when the last such assessment was undertaken.

Non-linear, accelerating ice mass loss from Antarctica, as well as the world’s other great Ice sheet, Greenland, has major implications for the rate of sea level rise and the security of urban conurbations around the world.  More than half of the world’s population live in coastal cities, and rising sea levels represent a major risk to urban infrastructure as well as food, water and energy security.

It is becoming ever clearer that the Earth’s current energy imbalance because of global warming caused by an excess of greenhouse gases in the atmosphere because of fossil-fuel emissions is a major driver of climate change.  Compared to preindustrial levels, the levels of the main greenhouse gas in the atmosphere, carbon dioxide, has increased by over 45% and is now measured at 410 parts per million (PPM) compared to a pre-industrial level of 280 ppm.  Consequently, the average global temperature compared to an 1880-1920 baseline has increased by about 1.10C, although temperature increases in the polar regions has been far more extreme.  The last time the Earth was as warm as it is today, during the prior interglacial period of the Eemian, some 126,000 years ago, sea levels were between 6 and 9 metres higher at energy equilibrium compared to current levels.

Professor Obbard in his seminar emphasized the need for rapid cuts in carbon emissions as well as the development of carbon capture and negative emission technologies to avert climatic tipping points (where rapid, unpredictable changes in climate may occur), and what the United Nations has referred to as “abrupt and irreversible” climate change.

During his visit to Sun-Yat Sen University, Prof Obbard also attended a meeting of Working Group 1 of the Intergovernmental Panel on Climate Change who discussed the scope of the AR6 Report which is due in 2022.

For more information on climate change science, mitigation and adaptation contact Prof. Jeff Obbard at Tembusu Asia Consulting at jobbard@tembusuasia.com

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