"The loss of fertility in males as a result of climate change, particularly in the tropics, may be a better predictor of vulnerability to extinction"

"however, the loss of fertility in males - which occurs at temperatures much lower than lethal temperatures – was a better predictor of individual climate change vulnerability.

Although critical thermal limits could accurately assess the geographical distribution of vulnerability (that tropical species are more vulnerable to warming), male fertility limits were much better at estimating individual extinction temperatures, suggesting that critical thermal limits may overestimate extinction risk.

Male fertility thermal limits also showed a greater association with current habitat temperatures and rainfall than critical thermal limits, revealing that male fertility may also be more important for dictating species current distributions.

So, how much closer are species to their male fertility limits than their critical thermal limits?

Some of the rainforest species we examined currently experience maximum habitat temperatures around 7 °C below their critical thermal limit or in other words, their warming tolerance is around 7 °C"