A consistent climate change baseline for estuarine impact and adaptation planning along the New South Wales coastline

In the Australian state of New South Wales (NSW), over 80% of the population lives in the coastal zone and directly or indirectly benefits from estuaries as places of recreation, transport and trade (i.e. ports and shipping) or as providers of food and raw materials. Despite being considered particularly vulnerable to climate change, the extent to which estuaries will be affected by changing climate conditions remains poorly quantified. Estuaries are affected by climatic changes both in the upland catchment and the ocean. Consequently, assessing the impacts of climate change requires locally-relevant observations and projections of rainfall, air temperature, wind, sea levels, ocean acidity, ocean temperature and waves. For the NSW coastline, there is currently no data source that provides all this information in a single place. Here, we address this gap by synthesizing the best available data and relevant scientific literature into a summary table of recent historic (1950-2010) and likely future changes (2030 & 2080) in the NSW coastal climate, using an upper-end greenhouse gas scenario. The NSW and ACT Regional Climate Modelling (NARCliM), the most fine-scaled climate change information available for NSW, is statistically analysed to derive relevant climatic changes for the coastal zone. NARCliM does not simulate oceanic processes explicitly and additional data and information sources (i.e. in-situ gauges, buoys, reanalysis datasets) are used to generate consistent information for the remaining variables. This paper is intended to facilitate the prioritization of climate change risks for coastal impact and adaptation planning by providing a quick and holistic overview of climatic changes that natural and built systems are facing along the NSW coastline.