Climate change may kill 17% of all sea life by end of century

Ocean-dwelling species are two times more likely to be wiped out due to climate change than life on land, a study has found.

If the world's greenhouse gas emissions stay at the present rate, that means a 17 per cent loss of biomass the total weight of all the marine animal life by the year 2100, according to Tuesday's study in the Proceedings of the National Academy of Sciences.

To date, Earth's surface has warmed a full degree (1.8 degrees Fahrenheit).

Every additional degree will see the ocean biomass shrink by another 5 percent. Earth is currently on course to be around 4C hotter by 2100.

Bigger fish and marine mammals already devastated by overfishing, pollution and ship strikes will see especially sharp declines due to rising temperatures.

'DEAD ZONES'

Some regions will be hit much harder than others, the study found.

Climate change will reduce marine biomass by 40 to 50 percent in tropical zones, where more than half a billion people depend on the ocean for their livelihood, and two billion use it as their main source of protein, reports AFP.

Why oceans are important?

Oceans are a global force of nature that form the foundation of the blue planet on which we live. They cover 71% of our planet's surface and make up 95% of all the space available to life. They are a life-support system for Earth and a global commons that provide us with free goods and services, from the food we eat to the oxygen we breathe.

The oceans also regulate the global climate; they mediate temperature and drive the weather, determining rainfall, droughts, and floods. They are also the world's largest store of carbon, where an estimated 83% of the global carbon cycle is circulated through marine waters.

In the last 200 years, the oceans have absorbed a third of the CO2 produced by human activities and 90% of the extra heat trapped by the rising concentration of greenhouse gases.