Natural Sciences

Sea Level Rise Accelerates at Three Times Faster than Previous Decade.

Global mean sea level rise (GMSL) has been accelerating since the beginning of the twentieth century; from a rate of 1.1 ± 0.3 mm per year between 1901–1990 to 3.1 ± 1.4 mm per year during the period 1993–2012.

Data from tidal gauges has been supplemented in the last 20 years by sea level change altimetry observations from advanced global satellites, monitoring satellites such as NASA’s GRACE mission which allow scientists to estimate the contribution of land water and land ice to GMSL and marine in-situ measurements such as the Argo project which allow researchers to calculate thermostatic sea level changes from the ocean surface down to depths of 2km.

These advances in observations assist scientists in identifying and quantifying the main contributors to GMSL; land ice melt, the thermal expansion of the seawater due to higher sea temperatures and the impact of climate driven changes in land water stores by human activity which has influenced the dynamics of water exchange on a global scale.

New research based on data collated over an 11-year period (2005 to 2015), concurs that a “hiatus” in global warming was recognised during the first decade of this century but the trend during the last decade has accelerated at 0.27 ± 0.17mm/yr2, about 3 x faster than the previous decade.

They researchers conclude that after seasonal variations are removed the acceleration in GMSL is mainly due to three factors; a contribution from thermal expansion of the seawater 0.12 ± 0,06mm/yr2 which is an immediate response to the restart in global warming; 0.11 ± 0.02 mm/yr2 from declining land water storage and 0.04 ± 0.01mm/yr2 from land ice melt, seen as a direct consequence of global warming with a delayed response.

The research published in the December 2017 edition of the “Journal of Geophysical Research”, highlights the continued susceptibility of sea level rises from global warming and ongoing threats to coastal habitats.

This article was attributed and provided by PG International

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