Global negative emission land use scenarios and their ecological implications

Earth’s atmospheric CO₂ level has increased beyond 400 ppm and still continuing to rise. In fact, this is the highest level in the last 2 million years. It appears we are heading towards an overshoot of CO₂ concentration before stabilizing green house gases (GHGs) to keep global warming below dangerous level. In Paris on December 2015, the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC) agreed to strengthen the global response to the threat of climate change by keeping a global temperature rise this century well below 2° celsius above preindustrial levels and to pursue efforts to limit the temperature increase even further to 1.5° celsius. Can this level of CO₂ stabilization still be achieved? One core strategies in the mitigation mix are negative emissions technologies (NETs) which are also explicitly described as important options in many IPCC (AR5) CO₂ emission scenarios. Among others, BioEnergy with Carbon Capture and Storage (BECCS) are shown their potential for CO₂ removable from the atmosphere. BECCS as the NETs are most widely selected by integrated assessment models (IAMs) to meet the requirements of temperature limits of 2° and below. It is based on assumed carbon-neutral bioenergy combined with capture of CO₂ produced by combustion and its subsequent storage in geological or ocean repositories. BECCS is a net transfer of CO₂ from the atmosphere into geological layers. However, its credibility as a climate change mitigation option and their impacts to global and regional ecosystems are still unknown. To explore the ecosystem impacts of the large-scale deployment of negative emission land use scenarios, we review some papers that are analyzing global impacts of the land use scenarios on various factors of ecosystem services to look at the sustainability limits to their global large scale deployments. Ecological services implications of the NETs especially land demanding BECCS land use scenarios need to be addressed before implementing such projects not only for achieving global low carbon target but also achieving more comprehensive ecological sustainabilities to meet the sustainable development goals (SDGs).