From UPSC perspective, the following things are important :
Prelims level : Nothing much
Mains level : Climate change and warming oceans
As per a recent IPCC report, by 2100, oceans all over the world will absorb five to seven times more heat than they have done in the past 50 years if we do not reduce our emissions trajectory.
Importance of oceans
- Oceans cover more than 70% of the earth’s surface.
- They provide critical ecosystem services such as soaking up the heat and distributing it evenly.
Challenges due to warming oceans
- This will lead to global sea- levels rising by at least a meter. This will submerge several coastal cities, including Mumbai, Kolkata, Chennai, and Surat.
- Marine heatwaves are projected to be more intense. They would last longer and occur 50 times more often.
- Sea-level rise could also lead to an increase in the frequency of extreme weather events, which occur, for example, during high tides and intense storms.
- As the planet warms, it’s oceans get most of the extra energy.
- Hotter oceans also mean stronger cyclones and storms. This could lead to unprecedented volatility in several coastal regions. For instance, in 2014, Cyclone Nilofar was the first extremely severe cyclone to be recorded in the Arabian Sea in the post-monsoon season.
- Earlier, cyclones impacting the country generally originated in the Bay of Bengal and made their landfall on India’s eastern coast. Cyclone Nilofar did not make landfall but it led to heavy rains in the country’s west coast.
- In October last year, a higher than normal surge in sea-level due to the dual impact of Cyclone Luban and high tide swamped several beaches in Goa. Some of them went completely underwater for a few hours.
- Warming seas have changed cyclone behaviour in other ways as well. In 2017, Cyclone Ockhi, which originated in the Bay of Bengal, traveled more than 2,000 km to wreak havoc on India’s western coast — the first cyclone to do so in 30 years.
- The IPCC report warns of more “frequent El Nino and La Nina events”. These events in the Pacific Ocean are critically linked to the southwest monsoons in India. An El Nino caused a severe drought in the country in 2015.
- Countries will have to upscale efforts to check GHG emissions.
- Ramp up investments in infrastructure and knowledge systems to build up peoples’ resilience against extreme weather events.
- The latest IPCC report should serve as a wake-up call.