The most recent edition of the Earth-Science Reviews, an influential scientific journal, carries an article by Prof. Rosh Ranasinghe, specialist in Climate Change Impacts and Coastal Risk at UNESCO-IHE. The article is intended as a ‘one-stop’ review of the most likely climate change impacts on global coastal change.
Promoting best practice at the local level
According to Rosh, the genesis of the article was ‘demand driven’, as he repeatedly encountered frontline professionals around the world - whether government managers, policy makers or engineers – who expressed an acute need for such a planning aid.
Rosh acknowledges that while a greater awareness of climate change induced coastal change has indeed resulted in more impact assessments overall, efforts have been too variable in both focus and quality. The likelihood that climate change will further alter the shape of the world’s coastlines, combined with the ever increasing expansion of coastal settlements, highlights the importance of making these endeavours more accurate. Indeed along with the potentially devastating environmental and social impact, it is estimated that the economic costs of climate change impacts on coasts could run into the trillions of dollars.
The review limits its scope to open sandy coasts, which comprises up to 40% of the world's coastline. It addresses coastal vulnerability to the main climate change drivers of fluctuating sea level, wave conditions, storm surge and river-flows; outlining their potential impact when viewed against time scales ranging across episodic (hours-days), medium-term (years-decades), and long-term (decades-century).
Rosh’s work formalises a standard ensemble modelling framework for local scale climate change impact assessments and strongly promotes risk informed decision making for ‘no-regrets’ coastal zone management and planning for the future.
Indeed the value of the quantitative coastal risk assessment approaches suggested by Rosh was recently highlighted in the aftermath of an Australian East Coast storm which left four people dead and caused over $ 50 million worth of damage. The Sydney Morning Herald, a prominent Sydney newspaper, stated that Rosh’s model results in fact correctly predicted the damage months before the storm occurred, referring to a previously published UNESCO-IHE led study which had identified an economically optimal ‘setback line’ along the affected coastline, whereby settlement on the seaward side was deemed inadvisable.
Rosh stresses the need for development of ‘multi-scale’ modelling, which integrates the various spatio-temporal scales (ranging from 10 m to 100 km and from days to centuries) at which climate change impacts occur. While acknowledging that this may be several years away, as an interim solution, he proposes the strategic use of existing modelling methods to derive qualitative assessments of climate change impacts on coasts.
Read the original article here.