Welcome!

 Background

As we are, by now, obviously aware that man-made changes to our environment have altered the natural balance of the environment almost irreparably. The Intergovernmental Panel on Climate Change has very nicely described how humans have altered our environment at an “unprecedented” pace. Some salient points still need to be listed in order to understand the gravity of the situation.

• Human emissions of greenhouse gases such as carbon dioxide have already warmed the climate by 1.1 ˚C

  

  since pre-Industrial times according to the IPCC report published in 2023. The global average temperature might reach or exceed 1.5 ˚C within the next decade, leading to widespread damaging effects across the globe.

• Global carbon dioxide emissions have continued to rise following the 2015 Paris Accord. Only in 2020 the emissions declined due to the pandemic.
• Natural disasters are becoming more frequent across the globe, e. g.,  forcing an estimated 3.4 million people in the U.S. to leave their homes in 2022, according to Census Bureau data. The National Oceanic and Atmospheric Administration said that 18 extreme weather events had each caused at least $1 billion in damage.

Solution Space

Obviously, there needs to be a multi-pronged strategy to reduce the relentless rise of greenhouse gases in the atmosphere. There are two broad strategies – 1) Reducing the carbon footprint of human activities towards the goal of ‘Carbon-neutral’ and 2) removing the CO2 already emitted and existing in the atmosphere and also till the time we achieve carbon neutrality. To achieve success in our fight to save the environment, we will need to successfully implement both strategies.

Carbon sequestration

Here, we are primarily focusing on the second strategy of ‘removing the existing CO2 in the atmosphere’.

To prevent the increase in temperature beyond 1.5 degrees C, about 10 billion tons of CO2 will have to be removed per year from the atmosphere by 2030 and about 25 billion tons CO2 per year by 2050 (see BP Energy Outlook).

Carbon sequestration is a possible solution which can be defined as the capture and storage of carbon in solid forms that would be otherwise emitted into the atmosphere. At present, industrial solutions for carbon removal are being actively researched. These include – Biomass Carbon Removal and Storage (BiCRS) and Direct Air Capture and Carbon Sequestration (DACCS) which would inject concentrated atmospheric CO2 underground and sequester it. However, these solutions are expensive, and the two strategies combined are projected to only remove 300 million tons of CO2 which will hardly make a dent in the inventory of atmospheric CO2.

Currently, land- and ocean-based natural ecosystems already act as very effective, free, and natural ‘carbon sinks.’ Carbon sinks are an example of natural removal as they are simply the uptake and storage of CO2 by land- and ocean-based ecosystems. At present, there is an exchange of about 450 billion tons of CO2 per year at the soil-air interface with soil retaining ~2% of CO2 per year. Similarly, the marine biological pump removes about 150 billion tons of CO2 of which about 10 billion tons of CO2 remains in the ocean. Thus, both land and the ocean have large capacities to hold carbon that can be leveraged to remove a lot more atmospheric CO2. This can be done by reducing the amount of carbon that gets oxidized back to CO2 every year on land and in the ocean. Simple! Not so…we need to find creative out-of-box solutions to accomplish this at a large scale and in a short time. Here, we are investigating the role that clay minerals can play in removing atmospheric CO2 in the ocean.

 

 Clay minerals to remove carbon present near the ocean surface

We have found that clay minerals sprinkled on ocean surface can remove dissolved organic carbon and initiate a pathway recruiting the marine biological pump that would increase both the magnitude of particulate organic carbon flux to depth and its remineralization length-scale. This would allow a larger fraction of atmospheric carbon to be buried at depth exceeding ~500m where it is isolated from the atmosphere over centuries. Smart targeting of oceanographically relevant sites would be needed to slow down the yearly growth of atmospheric CO2. We think that clay-mineral seeding of the sea-surface can be scaled up in relatively short-order.

Read more about the experiments being conducted currently by the Sharma Lab in our Research page. See Dr Sharma’s latest talk in Ceraweek on clay minerals sequestering carbon here – https://ceraweek.com/speakers/mukul-sharma/