Climate Change
Explainer: What Are Carbon Sinks?
Carbon sinks are carbon reservoirs and conditions that take-in and store more carbon than they release
Highlights
- Carbon sinks can serve to partially offset greenhouse gas emissions
- Forests and oceans are large carbon sinks
- Net zero requires removal of as much CO2 from the atmosphere as released
New Delhi: The Intergovernmental Panel on Climate Change (IPCC), the United Nations body for assessing the science related to climate change, recommends the world to attain net zero by 2050. The concept of net zero emissions requires that carbon dioxide (CO2) emitted must be offset by an equivalent volume of CO2 removed from the atmosphere. The two main approaches to absorb CO2 are – natural sinks like forests and wetlands; technological sinks known as carbon dioxide removal (CDR) tech such as carbon capture and storage.
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What Is A Carbon Sink?
The UN Climate Change defines ‘carbon sinks’ as carbon reservoirs and conditions that take-in and store more carbon than they release. Trees and plants, for example, absorb carbon dioxide, release oxygen and store the carbon. Carbon sinks can serve to partially offset greenhouse gas emissions. Forests and oceans are large carbon sinks.
Typically, CO2 emissions released in the atmosphere are absorbed by the land, ocean and some could accumulate in the atmosphere. Today we are releasing CO2 beyond the cleansing capability of the planet. Therefore, the accumulation in the atmosphere has become excessive and that is what is known as increasing atmospheric concentration of CO2 and is causing global warming, said Avantika Goswami, Deputy Programme Manager, Climate Change at Centre for Science and Environment (CSE).
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Planet’s Natural Sinks
Land Sinks
Land-based sinks include forests, croplands, and wetlands. Ms Goswami says that land currently absorbs about 30 per cent of the excess CO2 that is released through human activities like the burning of coal, oil, and cutting of forests.
According to a report published in Journal Nature in January 2021, forests absorb twice as much carbon as they release each year, absorbing a net 7.6 billion metric tonnes of carbon dioxide annually.
Peatlands are a type of wetland that occurs in almost every country on the globe. They store vast amounts of carbon—twice as much carbon as all the world’s forests, stated the United Nations Environment Programme on World Wetlands Day in 2019.
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Ocean Sinks
Oceans also act as a carbon sink and that is what has led to ocean acidification because the oceans have more carbon dioxide than what is healthy for them, said Ms Goswami.
In April 2021, UNESCO warned that the oceans’ ability to contribute to climate regulation may decline and even be reversed in the future. The oceans that are now the blue lungs of our planet, could end up contributing to global warming.
The Impact Of Natural Sinks In Absorbing Carbon
As per UNESCO, without oceans and land sinks, atmospheric CO2 levels would be close to 600 ppm (parts per million), 50 per cent higher than the 410 ppm recorded in 2019, which is already well above the agreed target of limiting global warming to two degrees Celsius.
Technological Sinks
Some of the technological solutions for capturing carbon are carbon capture and storage (CCS) and direct air capture and storage (DACS). CCS is a technology to capture waste CO2 from large sources such as factories, coal power plant or fossil fuel power plants, before it enters the atmosphere and store it underground for centuries.
As of 2020, the world had 26 operational CCS facilities capturing 36-40 megatonnes of CO2 per year, according to the Global CCS Institute, an international think tank. Of them, 24 were in industries and two in coal power plants.
Talking about the cons of CCS, Chandra Bhushan, CEO, iFOREST said,
The assumption is that the oil and gas wells or geological formation where CO2 will be pumped will be sealed for millennia. There are a lot of uncertainties including earthquakes which could disturb the geological formation or leakages which is not uncommon. And then what happens? You will have a large amount of CO2 there in the geological formation which is being emitted. This technology has been used but it’s very expensive to capture, separate, purify and transport it to places where geological formations are there and they do not exist at all places. It’s relatively cheaper if you are capturing near a gas or oil well but it’s quite expensive if geological formations are hundreds and thousands of kms away.
On the other hand, DACS is a technology that captures carbon directly from the air, rather than capturing it from major sources such as power plants or factories. The technology consumes electricity to do this, making it expensive. Mr Bhushan informed that the first pilot plant has just been set up in Iceland at a cost that is so exorbitant which doesn’t make any sense.
The Way Forward For Carbon Capture
Natural sinks are diminishing and some of them might become emitters. Siberian permafrost (frozen soil) will become a large emitter of Methane. Forest fires are a large emitter of CO2. On one hand, we have to deal with what we are burning right now to meet our energy requirements and on the other hand, we will have to deal with what happens when oceans become net emitters or forest fire is uncontrollable.
The first objective is to cut your emissions very quickly. From renewables to batteries to hydropower to carbon-neutral biomass to geothermal, there are umpteen technologies we haven’t tried. We are only talking about solar. We are still meeting about 70 per cent of our energy needs by burning fossil fuels. Only 25 per cent comes from non-fossil resources out of which the majority is nuclear and hydropower. Solar and wind are still very small. The world has not changed its energy track. Remember, technologies like CCS and DACS are last resort technologies. These are not first option technologies. These technologies will only be used when you have to take out a few million tonnes to become net zero. But if we think that we can continue burning fossil fuels and extract them from technologies then that’s not a viable option because fossil fuel is not only about CO2, said Mr Bhushan.
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NDTV – Dettol have been working towards a clean and healthy India since 2014 via Banega Swachh India initiative, which is helmed by Campaign Ambassador Amitabh Bachchan. The campaign aims to highlight the inter-dependency of humans and the environment, and of humans on one another with the focus on One Health, One Planet, One Future – Leaving No One Behind. It stresses on the need to take care of, and consider, everyone’s health in India – especially vulnerable communities – the LGBTQ population, indigenous people, India’s different tribes, ethnic and linguistic minorities, people with disabilities, migrants, geographically remote populations, gender and sexual minorities. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign will continue to raise awareness on the same along with focussing on the importance of nutrition and healthcare for women and children, fight malnutrition, mental wellbeing, self care, science and health, adolescent health & gender awareness. Along with the health of people, the campaign has realised the need to also take care of the health of the eco-system. Our environment is fragile due to human activity, that is not only over-exploiting available resources, but also generating immense pollution as a result of using and extracting those resources. The imbalance has also led to immense biodiversity loss that has caused one of the biggest threats to human survival – climate change. It has now been described as a “code red for humanity.” The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene. Banega Swasth India will also be taking forward the dream of Swasth Bharat, the campaign feels that only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and the country can become a Swasth or healthy India.
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