I Apologize sidd .
I had the term wrong.
I meant the draw down of atmospheric CO2 being impossible with present technology at a palatable economic cost.
I think the term that is being used is "Negative Emissions Technology" abbrievated NET. The linked paper provides an overview of the current status of NET.
https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2016.0447Negativeemissions technologiesandcarbon captureandstoragetoachieve theParisAgreement commitments
R.StuartHaszeldine,StephanieFlude,Gareth JohnsonandVivianScott
SchoolofGeoSciences,UniversityofEdinburgh,Edinburgh,EH93FE, UK RSH,0000-0002-7015-8394
How will the global atmosphere and climate be protected? Achieving net-zero CO2 emissions will require carbon capture and storage (CCS) to reduce current GHG emission rates, and negative emissions technology (NET) to recapture previously emitted greenhouse gases. Delivering NET requires radical cost and regulatory innovation to impact on climate mitigation. Present NET exemplars are few, are at small-scale and not deployable within a decade, with the exception of rock weathering, or direct injection of CO2 into selected ocean water masses. To keep warming less than 2°C, bioenergy with CCS (BECCS) has been modelled but does not yet exist at industrial scale. CCS already exists in many forms and at low cost. However, CCS has no political drivers to enforce its deployment. We make a new analysis of all global CCS projects and model the build rate out to 2050, deducing this is 100 times too slow. Our projection to 2050 captures just 700 Mt CO2 yr−1, not the minimum 6000 Mt CO2 yr−1 required to meet the 2°C target. Hence new policies are needed to incentivize commercial CCS. A first urgent action for all countries is to commercially assess their CO2 storage. A second simple action is to assign a Certificate of CO2 Storage onto producers of fossil carbon, mandating a progressively increasing proportionofCO2 tobestored.NoCCSmeansno2°C.
I think that the conclusions are pessimistic given that renewables are rapidly replacing fossil fuels, so CCS won't be needed for existing fossil fuel infrastructure. However, the best IPCC scenario, RCP 2.6, requires the deployment of NET to reduce carbon concentrations in the atmosphere.
One of the promising NETs available today is biomass burning with CCS. Production of biochar with CCS is also a promising NET that could provide for soil restoration (helping improve that carbon sink) as well as biofuels for industrial feedstocks and aviation. While those last two aren't negative emissions, they're at least carbon neutral and will allow us to completely transition off of fossil fuels.