All options, not silver bullets, needed to limit global warming to 1.5 °C: a scenario appraisal
Climate science provides strong evidence of the necessity of limiting global warming to 1.5 °C, in line with the Paris Climate Agreement. The IPCC 1.5 °C special report (SR1.5) presents 414 emissions scenarios modelled for the report, of which around 50 are classified as '1.5 °C scenarios', with no or low temperature overshoot. These emission scenarios differ in their reliance on individual mitigation levers, including reduction of global energy demand, decarbonisation of energy production, development of land-management systems, and the pace and scale of deploying carbon dioxide removal (CDR) technologies.
The reliance of 1.5 °C scenarios on these levers needs to be critically assessed in light of the potentials of the relevant technologies and roll-out plans. We use a set of five parameters to bundle and characterise the mitigation levers employed in the SR1.5 1.5 °C scenarios. For each of these levers, we draw on the literature to define 'medium' and 'high' upper bounds that delineate between their 'reasonable', 'challenging' and 'speculative' use by mid century. We do not find any 1.5 °C scenarios that stay within all medium upper bounds on the five mitigation levers. Scenarios most frequently 'over use' CDR with geological storage as a mitigation lever, whilst reductions of energy demand and carbon intensity of energy production are 'over used' less frequently. If we allow mitigation levers to be employed up to our high upper bounds, we are left with 22 of the SR1.5 1.5 °C scenarios with no or low overshoot.
The scenarios that fulfil these criteria are characterised by greater coverage of the available mitigation levers than those scenarios that exceed at least one of the high upper bounds. When excluding the two scenarios that exceed the SR1.5 carbon budget for limiting global warming to 1.5 °C, this subset of 1.5 °C scenarios shows a range of 15–22 Gt CO2 (16–22 Gt CO2 interquartile range) for emissions in 2030. For the year of reaching net zero CO2 emissions the range is 2039–2061 (2049–2057 interquartile range).
Research news | 2022-05-22
Celebrating International day for biodiversity
May 22 is the International Day for Biodiversity and we celebrate it by highlighting our research on the topic
Research news | 2022-05-20
Relaunch of hub on environment, climate and security
Swedish government launches second phase of the Stockholm Hub on Environment, Climate and Security, building knowledge on how climate and environmental change lead to human insecurities
Research news | 2022-05-16
The effects of less, but better meat production
Study captures the real-world experiences and effects of a farm’s journey towards sustainability
Research news | 2022-05-14
Our engagements during Stockholm +50
When and where to find us during the international environmental meeting in Stockholm 2-3 June
Research news | 2022-05-10
Centre joins SEK 45 million landscape programme
LAND-PATHS programme will engage with ordinary citizens to develop more sustainable and integrated decision-making processes
Research news | 2022-05-09
Three ways games can break sustainability deadlocks
Played by the right people, strategy games can break free from established norms and support more transparent democratic dialogues