Hendrik G. van Oss 2011 The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO₂ emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry. application/pdf en Proparco Reducing cement's CO₂ footprint article