W.LIV.2025 - Updating Shipping Route Data for the Heat Stress Risk Assessment (HSRA) model

Summary

The current heat stress risk assessment (HSRA) model relies on historical weather data for ship routes to port and port climatic data to predict risk. Uncertainty about the climatic conditions and variability makes ships sailing north of the equator at some times of the year at increased risk of heat stress. There is an imperative to update and better understand ship sailing routes and the risks of sailing all year round. This will help better manage sailing into poor climatic conditions and subsequently reduce the risk of heat exposure to livestock. This will include analysis of heat stress and cold stress risk for some shipping routes at various times of the year. This project will deliver an updated validated data set of up to sailing routes to 63 ports that will then be fed into the HSRA model as it undergoes an upgrade simultaneously.

Objectives

The objective of this report is to provide the technical description of how up-to-date monthly WBT climatological statistics - based upon bias-corrected ERA5 data for the period 2011-2020 - were produced. This is critical information needed to inform livestock exporting operators out of Australia of the likely heat stress risks for the oceanic component of shipping routes to key Middle Eastern and Asian destination ports. The actual WBT datasets described here are separately provided to the MLA and are being integrated into the new version of the HSRA model.

This report complements the reports prepared by Buckley (2021) - W.LIV.2017 ”Final Report Collection and Validation of Island & Selected Additional Coastal Ports for Oceanic Bias Correction of ERA5 WBTs for the HSRA Model”, W.LIV.2017 “Final Report Middle Eastern and West Asian Port Climatologies”, and W.LIV.2017 “Final Report South & East Asian Port Climatologies” that provide the WBT climatologies for destination ports across the Middle East and Asian ports north of the equator.

This analysis and bias correction were undertaken by Drs Cindy L. Bruyère and James M. Done at the US National Center for Atmospheric Research (NCAR) / University Corporation for Atmospheric Research (UCAR), with assistance from Dr Bruce Buckley, Weather Australia, using the European Re-Analysis – 5 (ERA5) datasets. The ERA5 datasets are the highest quality reanalysis data available across the oceanic regions of interest.

Key findings

The research project demonstrated that quantile-quantile bias-corrected ERA5 WBT data can accurately represent the actual WBT climatology — as defined by the numerous weather station validation climatologies that lie across the routes traversed by livestock from Australia to the Middle East and Asian ports. Bias-corrected WBT climatologies were produced for each percentile from 1% to 100% (including 99.9%), for each month of the year, and every grid point in the domain.

The climate change-induced trends in the WBTs were also quantified across the domain. These vary by location, with both positive and negative trends identified. The most substantial increases were found to occur in the Middle East, with the effects most prominent in the months of September and October.

Benefits to industry

The Australian livestock export industry now has access to the latest and most accurate WBT
climatologies along every route used between Australia and the Middle East and Asian ports across time, along with updated destination port WBT climatologies. This will allow industry to have greater confidence in quantifying the heat stress risks along the routes and to the destinations of interest across all times of the year. In addition, the industry will be able to optimise stocking densities and stock selection types with greater confidence and better manage voyage timing as a result of this new and improved analysis.

The industry also has quantitative evidence that there are ongoing increases in the WBTs along several key routes and for many of the destination ports due to ongoing climate change effects. Therefore, the observed trends can be incorporated into heat stress risk assessments in the coming years as the WBT climatologies continue to change.

MLA action

Publishing the final report on the MLA R&D website.

Future research

As climate change is accelerating, the results of this and the companion studies should be updated in approximately five years as the statistics of wet- and dry-bulb temperatures will have changed by that time. WBTs can be expected to rise for most locations where heat stress risks are most likely as the climate warms, and hence the risk of heat stress will also worsen. Conversely, there will be a gradual decline in the risk of cold stress for most locations.

Future research to investigate the ability and value arising from dynamic and statistical models that predict actual WBT probabilities along key shipping routes may be of value. Dynamic predictors that consider the current state of the atmosphere and oceans along the shipping routes and at destination ports may be of value if a dynamic tool for assessing heat stress risks can be shown to improve management of trade heat stress risk over the existing system.