Climate warming is expected to have a significant impact on terrestrial ectotherms, with effects varying by latitude. Tropical ectotherms, despite experiencing smaller temperature increases, are at higher risk of population decline due to their limited thermal tolerance and proximity to their optimal temperature. In contrast, higher latitude species, with broader thermal tolerance and cooler climates, may benefit from warming. This study integrates empirical data on insect thermal tolerance with climate projections to estimate the impact of warming on insect fitness across latitudes. Results show that warming in the tropics is likely to have the most detrimental effects, while higher latitudes may see increased fitness. Similar patterns are observed in vertebrates, suggesting a general trend for terrestrial ectotherms. The study highlights that the greatest extinction risks from global warming may occur in the tropics, where biodiversity is highest. The impact of warming is influenced by factors such as thermal tolerance and thermal safety margin, which are key indicators of how organisms respond to temperature changes. The study also notes that while adaptation, acclimation, and migration may mitigate some effects, tropical ectotherms remain at high risk due to their limited ability to adapt. The findings emphasize the need for further research to understand and predict the broader implications of climate change on biodiversity.Climate warming is expected to have a significant impact on terrestrial ectotherms, with effects varying by latitude. Tropical ectotherms, despite experiencing smaller temperature increases, are at higher risk of population decline due to their limited thermal tolerance and proximity to their optimal temperature. In contrast, higher latitude species, with broader thermal tolerance and cooler climates, may benefit from warming. This study integrates empirical data on insect thermal tolerance with climate projections to estimate the impact of warming on insect fitness across latitudes. Results show that warming in the tropics is likely to have the most detrimental effects, while higher latitudes may see increased fitness. Similar patterns are observed in vertebrates, suggesting a general trend for terrestrial ectotherms. The study highlights that the greatest extinction risks from global warming may occur in the tropics, where biodiversity is highest. The impact of warming is influenced by factors such as thermal tolerance and thermal safety margin, which are key indicators of how organisms respond to temperature changes. The study also notes that while adaptation, acclimation, and migration may mitigate some effects, tropical ectotherms remain at high risk due to their limited ability to adapt. The findings emphasize the need for further research to understand and predict the broader implications of climate change on biodiversity.