New research: Lethal Humidity is amplifying climate-related shocks and impacting millions
The Australian Strategic Policy Institute has today launched the first global research outcome under the framework of the Lethal Humidity Global Council.
The report, Lethal humidity and the systemic risks of climate change by Dr Robert Glasser, warns that some of the world’s most densely populated regions — home to hundreds of millions of people — are rapidly approaching lethal humidity thresholds.
Drawing on historical case studies from the US, South Asia and Brazil, the report details how humid heatwaves have overwhelmed hospitals and emergency services, triggered power outages and water-system failures, disrupted food systems and disproportionately affected poorer and more vulnerable communities.
It warns that climate change is also increasing the likelihood of cascading and compounding disasters, where humid heat interacts with floods, droughts, sea-level rise, storms, infrastructure failures and disease outbreaks.
It also highlights the growing risks facing tropical coastal megacities where, by 2100, around 3 billion people could be living in urban areas exposed simultaneously to extreme humid heat, flooding, storm surges and deep social vulnerability.
The report notes that Indonesia is particularly vulnerable to these dynamics. Humid-heat extremes are rapidly becoming a defining climate risk, with humidity remaining high throughout both the dry and wet seasons. The report warns that humid heat, combined with worsening flooding, drought, and sea-level rise, could produce severe cascading societal impacts across the archipelago, including food insecurity and the displacement of large segments of the population. Research suggests that in just one decade Indonesia has emerged as having the world’s fifth largest exposure of vulnerable populations to heatwave days, behind China, India, Japan and the United States.
China is geopolitically pivotal, yet its exceptional and rapidly growing exposure to humid heat and other climate hazards – posing significant risks to its future prosperity and stability — has been largely overlooked by policy analysts. The report underscores research suggesting that, in less than a decade, a heatwave as severe as China’s worst on record (2013) could occur approximately once every three years and, at 2°C of warming, every other year.
Included in the recommendations to mitigate the substantial risks associated with the emergence of widespread lethal humidity events in the Asia Pacific, the report calls for:
- Increased investments in research and planning, especially in developing countries;
- Addressing the interactions between humid heat and other climate hazards to inform national adaptation planning processes; and
- The development and adoption of Heat Action Plans that factor in humidity and human physiology in early warning models.
The report notes keeping people cool in a warming climate is a “global grand challenge”. Dr Glasser emphasises that phasing out fossil fuels and increasing the roll-out of renewable energy to achieve Real Zero emissions as quickly as possible is essential to change the dire trajectory of increased lethal humid heat events.
Read the full report on the Australian Strategic Policy Institute website here.