(detailed explanation not according to the parameters of word limit)
In its report released at the end of a meeting in Seoul, the Intergovernmental Panel on Climate Change has made projections for how the rise in global average temperatures can be restricted within 1.5°C of pre-industrial times. It has presented four possible pathways. which involve Carbon Dioxide Removal (CDR) in varying amounts. The pathways account separately for contributions of fossil fuel and industry, Bioenergy with Carbon Capture and Storage (BECCS), and removals in the Agriculture, Forestry and Other Land Use (AFOLU).
In each pathway, the global average temperature is projected to overshoot the 1.5°C target by some amount before returning to that level by the end of this century. Each looks at a different scenario of the global energy demand:
P1: A scenario in which social, business, and technological innovations result in lower energy demand up to 2050 while living standards rise, especially in the global South. A down-sized energy system enables rapid decarbonisation of energy supply. Afforestation is the only CDR option considered; neither fossil fuels with CCS nor BECCS are used.
P2: A scenario with a broad focus on sustainability including energy intensity, human development, economic convergence and international cooperation, as well as shifts towards sustainable and healthy consumption patterns, low-carbon technology innovation, and well-managed land systems with limited societal acceptability for BECCS.
P3: A middle-of-the-road scenario in which societal as well as technological development follows historical patterns. Emissions reductions are mainly achieved by changing the way in which energy and products are produced, and to a lesser degree by reductions in demand.
P4: A resource and energy-intensive scenario in which economic growth and globalization lead to widespread adoption of greenhouse-gas intensive lifestyles, including high demand for transportation fuels and livestock products. Emissions reductions are mainly achieved through technological means, making strong use of CDR through the deployment of BECCS.