Overfishing, pollution, habitat loss and climate change are all factors that are threatening marine life, raising their risk of extinction by 20 to 25 percent, according to new research.

"Until now, there has been a general assumption that, despite pressures on marine environments like pollution and overfishing, marine species are unlikely to be threatened with extinction," lead researcher Dr. Thomas Webb, from the University of Sheffield, said in a statement.

"We have shown that, on the face of it, there are indeed far fewer marine species of conservation concern; but much of this can be explained by the fact the conservation status of fewer marine species has been formally assessed," he added.

Climate change for one is already wreaking havoc on marine species, especially with the summer of 2014 seeing the warmest ocean temperatures ever recorded. For example, corals such as those in the Great Barrier Reef are to face the worst bleaching in decades, which will severely weaken the species. Also, climate change is setting conservation efforts back for endangered sea turtles, which are losing critical beach habitat due to rising sea levels.

But that isn't the only threat sea turtles have to worry about. Pollution is also putting these animals in danger, particularly those living around Hawaii where urban and farm runoff is causing tumors in these endangered species.

When most people think of species at risk of extinction, they picture land-based plants and animals like the iconic polar bear, which could see extinction in the year 2015. Meanwhile the millions of marine animals lurking beneath ocean waters are ill considered. Even the International Union for the Conservation of Nature has only assessed three percent of marine species in terms of their risk of extinction.

But this new study helps to shed light on marine life, which is normally considered fundamentally different from terrestrial systems.

"This is not to say that there are no important differences, but rather that assumptions need to be tested in order to make sensible decisions about managing the marine environment," Webb explained.

By taking this approach, they found that one in every four or five species, regardless if they live on land or in the sea, is at a heightened risk of extinction.

So with climate change, pollution, and habitat loss all looming threats to species around the world, hopefully this study will persuade researchers to start paying more attention to marine life in particular, which are also in need of some help.

The findings were published in the journal Current Biology.

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