If humanity does not reduce carbon dioxide emissions, by 2030, will begin the catastrophic loss of biodiversity in the tropics, and by 2050 this process will reach temperate latitudes. To such conclusions scientists have come, having compared the data of observations over 30,000 species from 22 climate models for three scenarios of anthropogenic emissions of greenhouse gases (intense, moderate and reduced). The results of a study published in the journal Nature.
Anthropogenic climate change has been ongoing for several decades and leads to the extinction of species in Earth’s ecosystems. Scientists have repeatedly predictedthat it will become the driving force of biodiversity loss, but found it difficult to name the date of the beginning of this process and set its pace: it will be gradual or occur suddenly. Often, researchers mention as a turning point the end of the XXI century, but this vague date seems so far away politicians and other decision makers. However, it is important now to begin to take action and to develop early warning for society, as well as more accurately assess the risk environment and identify key areas to explore biodiversity, where it will be closely monitored.
A group of scientists led by Christopher Trioson (Christopher Trisos) from the University of Cape town has developed a systematic approach to the study of biodiversity loss based on historical limits of the climatic boundaries of species and projections of climate change.
The climatic boundaries of a species is the range of climatic conditions in space and time in which the species has been recorded in the wild. The projected date on which these limits can be exceeded due to climate change in the selected areas, the authors of the study called the climate horizon: beyond the evidence of ability to persist in the wild do not exist. Beyond this horizon occurs in the best case, the uncertainty of the preservation of the species, and at worst its local extinction.
The scientists also introduced the term “horizontal profile” — so named graph which illustrates the cumulative percentage of species outside their climatic horizons over time. The shape of this profile is able to reflect the risk of sudden disturbances.
To build a horizontal climatic profiles, the researchers used information about living organisms from maps of natural habitats, created by experts at the International Union for conservation of nature and BirdLife International. The study included birds, mammals, reptiles, amphibians, fish, invertebrates, and environment-forming corals and sea grass — a total of 30562 species.
Meteorological data and climate predictions from 1850 to 2100 were taken from 22 climate models. The authors decided to stick with the scenario approach in relation to greenhouse gas emissions because their exact amount in the future is unknown. The first scenario (RCP 2.6) are valid with a significant reduction in emissions from the current level, the second (RCP 4.5), if a moderate restriction, and three (RCP 8.5) — with unlimited intense emissions.