One of the potentially most serious conservation problems is the synergistic effect of habitat fragmentation and climate change. As the climate warms, individual species of plants and animals will be forced to adjust if they can, as they have in the past. During the Ice Age transition many species survived by moving to appropriate habitats. Today such dispersal is more difficult because they need to travel across freeways, agricultural areas, industrial parks, and cities. An even further complication arises with the imposition of the direct effects of changes in CO2, which can change terrestrial, aquatic, and marine primary productivity, drop the pH of the oceans significantly, and alter the competitive relations among plants and animals.

Conservation biologists not only need to anticipate the phenology and movements of individual species in response to climate change but must also project potential changes to biological communities. Disruption of competitive or predator-prey interaction could jeopardize sustainability of ecosystem services on which we rely and lead to numerous extinctions. This is one of the most important challenges for conservation biologists in the next several decades as extensive land use and rapid climatic changes are likely to accelerate.