Credible Pathways to 1.5 °CFour pillars for actionin the 2020s

Introduction
Global energy‐related CO2 emissions rose 0.9% in 2022, reaching a new all‐time high of 36.8 Gt (IEA, 2022a).1 Land‐use related CO2 emissions remained at around 6 Gt in 2022. At the same time, record high fossil energy and electricity prices in many markets and new policies pushed energy efficiency and clean energy technology investments to new heights. Solar PV and wind each increased by around 275 TWh, a new annual record. Taken together, renewables covered more than 90% of electricity demand growth in 2022. Electric cars also surged, reaching 14% of global sales, up from 4% in 2020. Despite the continued growth of emissions in 2022, countries have increased their ambitions on climate change. According to analysis by the International Energy Agency (IEA), if countries implement in full and on time their nationally determined contributions (NDCs) and net zero pledges, as well as sectoral pledges such as the Global Methane Pledge and the Glasgow Leaders’ Declaration on Forests and Land Use, the world would be on a pathway to limiting warming to around 1.7 °C by 2100 (IEA, 2022b). This is substantially better than the trajectory implied by current policy settings, which would see warming of about 2.5 °C in 2100 However, it would still not limit warming to 1.5 °C. The Intergovernmental Panel on Climate Change (IPCC) has highlighted the significant risks of warming above 1.5 °C (IPCC, 2018; IPCC, 2021a; IPCC, 2022).

Energy sector CO2 emissions by scenario, 2010 – 2050, and temperature rise by scenario, 2100

zero net deforestation by 2030 and other land use actions Agriculture, forestry and other land use4 (AFOLU) isresponsible for around one‐fifth of global anthropogenic GHG emissions. Around one‐half of AFOLU‐related GHG emissions is from CO2, one‐third from methane, and the remainder from nitrous oxide (N2O). Addressing these emissions therefore plays an integral role in limiting warming to 1.5 °C. For example, in low‐ overshoot 1.5 °C scenarios considered by the IPCC, GHG emissions from AFOLU fall by 30‐ 63% between 2020 and 2030, with CO2 emissions reaching net‐zero around 2030. In these scenarios, the land sector also plays a key role in offsetting remaining GHG emissions from other sectors (e.g., from the energy sector, industrial processes and waste) by removing on average around 2.6 Gt CO2 per year between 2050 – 2100. AFOLU methane and N2O emissions are discussed in more detail in in Pillar 3.

Reduction in greenhouse gas emissions from AFOLU by measure in 2030

mitigation of non‐CO2 emissions
In addition to cutting CO2, rapid reductions in emissions of other GHGs are required in all scenarios which limit warming to 1.5 °C. These reductions of non‐CO2 GHGs, particularly of methane, have an outsized impact on global temperatures in the short term, as many of them are short‐lived climate forcers6 with powerful warming potentials but short atmospheric lifetimes (IPCC, 2021b). Cutting these emissions quickly can limit the duration and magnitude of the temperature overshoot above 1.5 °C. The temperature rise in recent years stands at around 1.2 °C above pre‐industrial levels. In the STEPS scenario, the temperature rise reaches around 1.9 °C by 2050, whereas in the NZE scenario, it is just over 1.5 °C by that time. About 40% of the additional warming in STEPS is caused by non‐CO2 emissions, with methane accounting for about 30% of the warming, nitrous oxide (N2O) for around 5%, and the other gases for around 5%.

Contribution to warming by GHG in STEPS vs NZE, 2022 – 2050 and temperature rise avoided by mitigation of non-CO2 GHGs.

Methane is responsible for around 30% of the rise in global temperaturessince the Industrial Revolution, and cutting methane emissions in the NZE Scenario has the single biggest impact after CO2 on limiting the temperature rise to 2050. One hundred and fifty countries have now joined the Global Methane Pledge, which was launched at COP26 in 2021 and aims to reduce methane emissionsfrom human activity by at least 30% from 2020 levels by 2030. The energy sector accounts for around 40% of total methane emissions attributable to human activity, second only to agriculture. In the NZE Scenario, methane emissions from the energy sector fall by around 75% between 2020 and 2030 and total methane emissionsfrom human activity fall by around 45%. The IEA’s latest update of its Global Methane Tracker found that methane emissions from oil and gas alone could be reduced by 75% with existing technologies. Around $100 billion in total investment is needed over the period to 2030 to achieve this reduction—equivalent to less than 3% of oil and gas net income in 2022. To address methane emissions from fossil energy production and consumption, countries covering over half of global gas imports and over one‐third of global gas exports released a Joint Declaration from Energy Importers and Exporters on Reducing Greenhouse Gas Emissions from Fossil Fuels at COP27 calling for minimizing flaring, methane, and CO2 emissions across the supply chain to the fullest extent practicable.

Total CO2 capture by sector and type in the NZE, 2030