Bringing together leading global experts
to exchange the latest scientific research, formulate rapid, large-scale policy solutions and advocacy that address the threats of lethal humidity and heat.
In 2023, the Intergovernmental Panel on Climate Change (IPCC) confirmed that one of the greatest hazards posed by near-term 1.5°C warming is the impact of “dangerous” humid heatwaves on human mortality.
This means that of all the dangerous impacts of the climate crisis, humid heatwaves are one of the nearest dangers we face according to major scientific consensus.
According to The National Aeronautics and Space Administration (NASA), for every degree the planet warms, humidity rises by about 7 per cent, because warmer air holds more water vapour. On this basis, it is likely that humidity has risen roughly 10 per cent since the 1850s. Increasing temperatures combined with high humidity can be lethal for humans. As our oceans warm from rising temperatures, more water evaporates, further increasing humidity in the air. This drives energy into the atmosphere and stirs up violent and frequent weather events like storms and hurricanes.
We are all at extreme risk from the combined threat of lethal humidity and heat.
For every 1°C the planet warms, humidity rises by about 7 per cent as water evaporates from our oceans and waterways [1].
In a dry environment, the upper limit to human survival is reached at around 54°C [2]; However,
with high humidity, our bodies can go into heat stroke from as low as 31-35°C [3].
That’s because with high humidity and heat our sweat can no longer effectively cool our bodies causing our core temperature to rise.
Without intervention, these conditions will cause your blood to thicken and organs to shut down, resulting in death within hours [2].
Real Zero refers to the complete elimination of all greenhouse gas emissions resulting from the extraction and burning of fossil fuels. Achieving Real Zero means a business has fully eliminated fossil fuels from its operations.
This approach differs from Net Zero targets, where carbon credits, offsets, unproven technologies like carbon capture and storage and over-inflated estimates of natural carbon sinks are used to create the appearance of reduced emissions without meaningful changes to business practices.
While Net Zero is widely adopted globally, it is increasingly criticised for failing to deliver genuine emission reductions. Entities that continue to rely on offsets or defer decarbonisation in favour of the hope that carbon capture and storage will scale are knowingly hindering the energy transition.
Without taking real action to substantially reduce fossil fuel use, as stipulated by the IPCC, the planet will continue to warm, exacerbating threats like lethal humidity. We urge major businesses to look beyond superficial ambitions and lay out practical and transparent plans to eliminate fossil fuels from their operations.
The Lethal Humidity Global Council is an assembly of dedicated leaders and global experts.
By joining, you become part of a pivotal group, shaping the global response to one of the most pressing issues of our time: lethal humidity and heat.
References
- NASA Jet Propulsion Laboratory (2022) Steamy Relationships: How Atmospheric Water Vapor Amplifies Earth’s Greenhouse Effect (https://climate.nasa.gov/explore/ask-nasa-climate/3143/steamy-relationships-how-atmospheric-water-vapor-amplifies-earths-greenhouse-effect/)
- Vanos et al. (2023) A physiological approach for assessing human survivability and liveability to heat in a changing climate. Nature Communications. (https://www.nature.com/articles/s41467-023-43121-5)
- Pennsylvania State University (2022) Humans can’t endure temperatures and humidities as high as previously thought (https://www.psu.edu/news/research/story/humans-cant-endure-temperatures-and-humidities-high-previously-thought/)
- Humidity refers to “absolute humidity”, the actual amount of water vapour in the air.
- High humidity refers to “relative humidity”, the ratio between the amount of water the air holds and the maximum amount it could hold.