“Climatic conditions help to shape various ecosystems and habitats around the globe. A particular climate can be a boon to one species and a devastation to another. As the climate changes, species and ecosystems respond by adapting, migrating, or reducing their population. Gradual shifts in the climate are easier to adapt to than abrupt swings, and this is certainly true for humans as well as other species. Studies of Earth's climatic history indicate that climates have changed in the past and resulted in dramatic shifts in ecosystems. The most recent geological period the Holocene (about last 10,000 years), however, has been unusually stable.”