The IUCN Convention on Biological Diversity Post-2020 Global Biodiversity Framework established a goal to protect at least 30% of earth’s ecosystems by 2030. A key component of this target is the need to conserve representative examples of all ecosystem types. Identification of ecosystem type and locality is an essential first step. We stratified World Terrestrial Ecosystems by zoogeographic regions to identify a total of 2,394 distinct terrestrial ecosystems. We classified these ecosystems by level of protection and conversion. Those identified as vulnerable, endangered, and critically endangered were deemed “crisis ecosystems;” they comprise a quarter of the 2,394 ecosystems. These crisis ecosystems may contain some relatively intact, functioning areas that could serve as the basis to maintain function and perhaps restore more extensive areas. The portion of crisis ecosystems that show low Human Modification are in what we deem “Last Chance Ecosystem” status. Globally, 2.6% of the terrestrial world (2.888 million km2) is in this stage and protection may help meet global representation targets and prevent ecosystem collapse.