_Article_  
Carbon Dioxide Uptake by Mortars and Concretes  
Made with Portuguese Cements  
[PERSON] 1,*(), [PERSON] 2, [PERSON] 3 and [PERSON] 4  
1 Spanish Institute of Cement and its Applications (IECA), C/[PERSON], 53, 28003 Madrid, Spain  
2 CIMNE--MADRID (UPC), P\" [PERSON], 41, 9\", 28010 Madrid, Spain;  
[EMAIL_ADDRESS]  
3 Department of Geological and Mines Engineering, Mine and Energy Engineering School,  
Technical University of Madrid (UPM), C/[PERSON], 21, 28003 Madrid, Spain; [EMAIL_ADDRESS]  
4 Oficemen, C/[PERSON], 53, 28003 Madrid, Spain; [EMAIL_ADDRESS]  
* Correspondence: [EMAIL_ADDRESS]; Tel.: +34-914429166  
Received: 16 December 2019; Accepted: 14 January 2020; Published: 16 January 2020  
**Featured Application: The Guidelines for National Greenhouse Gas Inventories, published in 2006 by the Intergovernmental Panel on Climate Change (IPCC), provides the procedure to calculate national GHGs emissions. However, it does not consider the net carbon dioxide emissions by the Portland cement clinker (released by the calcination process in the clinker fabrication minus concrete carbonation). This paper is a practical example of the net assessment to be followed.**  
**Abstract: As the cement industry continues to address its role in the climate crisis, Portugal's cement industry has started to calculate its net CO\({}_{2}\) emissions to become an entirely carbon neutral sector. These emissions are calculated by simply subtracting the total CO\({}_{2}\) uptake due to mortar and concrete carbonation from the total CO\({}_{2}\) that is emitted during the calcination process (clinker production). However, the procedures given in the Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas (GHG) Inventories to report GHG emissions do not contain any element that would grant this calculation method the status of an internationally recognized procedure. Therefore, some climate models are not accurate because they do not account for the carbon dioxide uptake due to concrete and mortar carbonation, as is evidenced in this paper. Climate models have improved since the IPCC's Fourth Assessment Report (AR4), but they can further improve by implementing carbon dioxide uptake by cement-based materials. In the present paper, a quick and easy method of evaluating net CO\({}_{2}\) emissions is utilized (simplified method) along with an advanced method. Portuguese net CO\({}_{2}\) emissions of the cement produced from 2005 to 2015 were calculated while taking carbon dioxide uptake during the service-life and end-of-life and secondary usage stages into account. Following the simplified method, 8.7 million tons of carbon dioxide were found to be uptake by mortars and concretes made with Portuguese cement over the ten-year period, in which 37.8 million tons were released due to the calcination process. In addition, an advanced method has been used to estimate the carbon dioxide uptake, which provided only slightly higher results than that of the simplified method (9.1 million tons).**  
**Keywords: climate change; climate models; carbon dioxide uptake; carbonation; CO\({}_{2}\) capture and utilization; cement industry; sustainability**