Tardigrades. 200x magnification. Darkfield microscopy. 

Tardigrades, also known as water bears, are members of the animal kingdom, but unlike most other animal taxa, they are microscopic. They get a lot of attention because of their resilience i.e. they can survive in extreme heat and cold, high pressure, and high radiation. They can also enter a dormant state wherein they slow down their metabolism to the point where they can dry themselves out-a process called cryptobiosis. When conditions become more favorable, and water is available again, they can reanimate themselves even decades after going dormant.      

Organisms die or succumb to environmental conditions out of their survival range because of the physiological stress it causes to them. Studies have been done to characterize the tardigrade genome that show that throughout evolutionary history, they’ve lost some of the stress response pathways that would cause death in other animals. Further, they have proteins that confer resistance to certain types of radiation, which is of interest to human biomedicine.  

All planetary life is fragile and geophysical, climatological, astronomical crises occur periodically that threaten life on Earth. Humans may not be able to survive certain events, but microbial life will surely endure, whether that be in the form of archaea, extremophilic bacteria, fungi, or resilient animals like the tardigrade. When we harm the planet through actions like those that contribute to climate change, we are really just hurting ourselves.