Global warming could lead to the largest migration of ocean species seen in 3 million years, according to new research. Fish native to cold waters could go extinct, or be forced to migrate toward the poles to escape heat. Meanwhile, marine species that thrive in warmer waters could move into areas currently occupied by cold-loving animals.
Global temperatures will rise more than 8.6 degrees Fahrenheit over the next century if current trends continue, environmentalists warn. The United Nations has set a goal of limiting global warming to 3.6 degrees Fahrenheit over the course of the 21st century, but even this may not prevent warming from having a major effect on wildlife, researchers warn.
Researchers examined three periods of geological history, including the middle Pliocene period, a time roughly 3 million years ago when temperatures were unusually warm. This information was collected along with data from the height of the most recent major ice age, the Last Glacial Maximum, lasting from 26,500 to 20,000 years before our time, and from contemporary records from 1960 to 2013. All of these records were compared with projections of global temperatures in the year 2100. These projections vary depending on the amount of greenhouse gases released over the next 85 years.
University of Science and Technology researchers in Lille, France, showed that if warming is near 8.6 degrees Fahrenheit, the warming would result in the largest mass migration of ocean species seen in 3 million years.
"If climate change is not tackled quickly, it will lead to a massive reorganisation of marine biodiversity on a planetwide scale," The National Centre for Scientific Research (CNRS) in France reported.
Even if the world meets the U.N. goal of limiting temperature rise below 3.6 degrees F, the change in species habitat would be three times greater than what was seen over the last 50 years.
An increase of just 2 degrees Fahrenheit by 2100 would have little effect on biodiversity, researchers concluded. This is the level predicted in the most optimistic forecasts being made today. Some aspects of this study were based on theories of how species will react to rising temperatures, as little objective data on these behaviors is available.
The study examined species which live in the top 650 feet of the ocean, since they have the greatest direct impact on human beings. There are still many things about the global ocean that scientists do not understand, and predicting behavior of such a complex system can be extremely challenging. However, the study clearly showed that greater amounts of warming will result in more extreme changes to biodiversity.
Warm water-loving species could see their habitats expand, but "this will not compensate global species extinction," the study warned.
Analysis of how varying degrees of rising global temperatures could affect biodiversity was published in the journal Nature Climate Change.
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