8 December 2015, The Conversation, Removing CO2 from the atmosphere won’t save us: we have to cut emissions now. Over 190 countries are negotiating in Paris a global agreement to stabilise climate change at less than 2℃ above pre-industrial global average temperatures. For a reasonable chance of keeping warming under 2℃ we can emit a further 865 billion tonnes of carbon dioxide (CO2). The climate commitments to reduce greenhouse gas emissions to 2030 are a first step, but recent analyses show they are not enough. So what are the options if we cannot limit emissions to remain within our carbon budget? Emitting more than the allowance would mean we have to remove carbon from the atmosphere. The more carbon we emit over the coming years, the more we will need to remove in future. In fact, out of 116 scenarios consistent with 2℃ published by the Intergovernmental Panel on Climate Change, 101 scenarios require the removal of CO2 from the atmosphere during the second half of this century. That’s on top of the large emission reductions required. So how do we remove carbon from the atmosphere? Several technologies have been proposed to this effect. These are often referred to as “negative emissions technologies” because the carbon is being removed from the atmosphere (in the opposite direction to emissions). In a study published today in Nature Climate Change, which is part of a broader release by the Global Carbon Project, we investigate how big a role these technologies could play in halting global warming. We find that these technologies might play a role in climate mitigation. However, the large scales of deployment currently used in most pathways that limit warming to 2℃ will be severely constrained by environmental and socio-economic factors. This increases the pressure to raise the level of ambition in reducing fossil fuel emissions now. Read More here