Due to climate change, the frequency and severity of heatwaves are quickly increasing. One worrying aspect is the possibility for the wet-bulb temperature (the humidity-corrected temperature achievable by evaporation) to stay above a critical threshold where sweating becomes inefficient. In this situation, a human could die of heatstroke even when staying in the shade and in front of a fan. The critical wet-bulb temperature was though to be around 35°C, but but recent research places it around 31°C for young adults and likely lower for older people.

Staying outside for several hours above the critical temperature would require active-cooling clothing, similar to the cooling vests used by fursuiters. I designed two systems that could be home-built and would not require electricity. The first uses parts of a backpack-mounted weed sprayer while the second is based on the smalls bags of dessicant often found in consumer goods packaging.