Climate change shrinks marine life richness near the equator

Published: 10th Apr, 2021

Recent research finds that a huge decline in biodiversity richness is observed near the equator.

Context

Recent research finds that a huge decline in biodiversity richness is observed near the equator.

About

About the Key findings of the report

The study finds that about half of the open water species have declined in the last 40 years up to 2010 in tropical marine zones worldwide.

Reasons behind the decline

The rising sea surface temperature is expected to be the reason behind the decline which has risen nearly 0.2? in the tropics.
Climate change is said to either plateau or declines the fish species at or above 20?. This will impact the marine species diversity distribution.

How the Ocean Temperature rises and impacts?

The ocean absorbs an excessive amount of greenhouse gas emissions which leads to the rise in ocean temperatures.
- The Fifth Assessment Report published by the Intergovernmental Panel on Climate Change (IPCC) in 2013 had revealed that the ocean absorbed more than 93% of the excess heat from greenhouse gas emissions since the 1970s.
The ocean also absorbs a higher amount of CO2, which leads to ocean acidification.
Ocean warming causes de-oxygenation which is a reduction in the amount of dissolved oxygen
It also causes the rise in sea level which results in thermal expansion of seawater.
The rise in CO2 causes acidification.
Acidification and ocean warming, in turn, impacts marine species and ecosystems.

Impact of rising temperature

The study shows a strong correlation between species decline and rise in temperature.
More changes are expected to be seen in Northern Hemisphere with more extent of warm water.
The migration of open-water species is also seen due to the temperature rise. Some species tend to migrate to cooler waters.
It is going to impact the fishing and tourism industries that rely on them.

Varied impact

A different level of impact is observed on the open water and deep-sea species.
The temperature rise is going to impact the coral reef as well but there is a concern regarding its mobility. In this case, the coral reefs are going to impact more extensively.

Open water species: Fishes, Whales, other free-floating marine species of mollusk and Echinodermata comes under this.

Deep-sea species: Mollusks, sponges, and Coral reefs come under this category.

How it can be mitigated?

It could be achieved by the targets set by achieving the targets of the Paris Agreement on climate change and by limiting the global average temperature increase to well below 2°C above pre-industrial levels.
The temperature rise can be a cop with the establishing marine protected areas and by putting the adaptive measures.
Management of protected areas can help in conserving and protecting the ecologically and biologically significant marine habitats.
Regulation of human activities in sensitive and protected areas can be managed to protect the species richness.
More investments in scientific research in measuring and monitoring ocean warming can help in the mitigation.

CURRENT AFFAIRS FOR UPSC IAS