Pathway comparison of limiting global warming to 2°C

Abstract

The Paris Agreement has set a goal to limit the global average temperature rise to within 2°C from the pre-industrial level. This study aims to explore the possible pathways to achieve this challenging goal by using the Global Energy and Environmental Policy Analysis module (GEEPA) of the China's Climate Change Integrated Assessment Model (C3IAM). Results show that a target temperature of 2°C dramatically reduces global CO2 emissions in the future. Under model parameters, by the end of this century, total global CO2 emissions will fall below 5 Gt, and cumulated CO2 emissions will be reduced to less than 1000 Gt. The key to meeting the 2°C target lies in the low-carbon transformation of energy and electricity systems. Implementation of climate policies and technical measures will progressively reduce conventional fossil energy consumption and replace it with low-carbon energy solutions. The electricity structure will gradually shift from dominance by conventional fossil energy to low-carbon energy, and even to zero-carbon electricity generation. We found that emission reduction pathways that include large amounts of fossil fuel power generation with CCS merely relying on subsidies may create higher GDP loss, but also that later penetration of negative emission technology can increase the carbon emission budget in the early stage.