anlomedad on Nostr: The #Wetbulb or heat-humidity index is a defined threshold regarding deadliness if ...

The #Wetbulb or heat-humidity index is a defined threshold regarding deadliness if you're a toddler or an old person or if you do strenuous work or if you are a marathon runner.
Animals, insects, fish, plants – they have their own species' threshold re Wetbulb and more general, regarding heat. Our life depends on insects, plants, fish and so on, we rely on a functional, reliable biosphere.
If our civilisation weren't imploding by 2040 – my guesstimate – but continue, humans in climate hotspots would probably soon become independent on "nature" for food and water, and instead produce food from mined chemicals.
But as it stands, such artificial food and water supply are decades away and in the meantime, the functional, reliable biosphere stays the basis for all our survival.

Read in a paper; forgot which : a heatwave renders some pollinator insects 50% infertile. Offspring conceived in the heatwave are also less fertile. Subsequent heatwaves further lower fertility.
______
Fewer pollinators also mean fewer birds, and fewer animals which eat birds, and then, less dead biomass in the soil which means fewer nutrients for plants and animals or humans who eat the plants.

From Duffy et al 2021: Plants can be defined by their preferred carbon-isotope uptake for photosynthesis which also defines their resilience toward heat: their photosynthesis reduces when °C moves beyond their threshold. Less photosynthesis means, plant growth is stunted in heat – which reduces carbon sinks (– and which also means that food gets scarcer for humans and all living beings when heatwaves pile up. )
Most plants are C3-plants and less heat-resilient than C4 plants. Of the C4 plants, most are a kind of grass. (Too bad humans can't live on grass alone. ..)
C3 plants thrive at 15°C. Beyond 15C, their photosynthesis reduces and CO2-respiration increases = growth is stunted. From ~24°C, the C3 plants respirate more than they take up = they stop growing. If heat continues, they wither and die.
C4 plants thrive at 26°C. At ~29°C, their CO2-respiration surpasses their CO2-uptake.
______
Less biomass due to heatwaves goes for ocean-dwelling creatures, too: heat breaks the nutrient cycle and also lowers the oceans' service as CO2 sink because fewer creatures (live and die and then) sink to the deep ocean floor, taking the carbon in their dead bodies with them.

Water evaporation in heat is another threshold for plants: can they replace the evaporated water in the cells or is the soil moisture too low because during a previous heatwave, the plants had already pulled out all the soil moisture to evaporate it as coolant ?
Being a plant or a wild animal in #climatechange is not fun because you can't buy water and food in a supermarket and you don't have electricity to switch on the AC.