The Summary for Policymakers states: "In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050 (2045–2055 interquartile range)." It also notes that "Reaching and sustaining net zero global anthropogenic CO2 emissions and declining net non-CO2 radiative forcing would halt anthropogenic global warming on multi-decadal timescales (high confidence)."

Chapter 2 states: "In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050 (2045–2055 interquartile range)." It further concludes: "Limiting warming to 1.5°C implies reaching net zero CO2 emissions globally around 2050 and concurrent deep reductions in emissions of non-CO2 forcers, particularly methane (high confidence)." The chapter explains that to stabilize global temperature at any level, net CO2 emissions must be reduced to zero, meaning sources and sinks are balanced.

The IPCC headline statements summarize: "In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050 (2045–2055 interquartile range)." Another statement notes: "Limiting global warming requires limiting the total cumulative global anthropogenic emissions of CO2 since the pre-industrial period, that is, staying within a total carbon budget (high confidence)."

Mitigation pathways limiting warming to 1.5°C (>50%) with no or limited overshoot reach 50% CO2 reductions in the 2030s, relative to 2019, then reduce emissions further to reach net zero CO2 emissions in the 2050s. Pathways limiting warming to 2°C (>67%) reach 50% reductions in the 2040s and net zero CO2 by the 2070s (medium confidence). In the AR6 scenario database, global emissions pathways limiting warming to 1.5°C (>50%) with no or limited overshoot reach net zero CO2 emissions between 2050–2055 (2035–2070) (median and 5–95th percentile ranges; 100% of pathways).

Mitigation pathways limiting warming to 1.5°C (>50%) with no or limited overshoot reach 50% reductions of CO2 in the 2030s, relative to 2019, then reduce emissions further to reach net zero CO2 emissions in the 2050s. Cumulative net CO2 emissions from 2020 to the time of net zero CO2 are 510 (330–710) GtCO2 in pathways that limit warming to 1.5°C (>50%) with no or limited overshoot and 890 (640–1160) GtCO2 in pathways limiting warming to 2°C (>67%). Only a small number of published pathways limit global warming to 1.5°C without overshoot over the course of the 21st century.

The report states: "In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050 (2045–2055 interquartile range)." It adds: "Limiting warming to 1.5°C implies reaching net zero CO2 emissions globally around 2050 and concurrent deep reductions in emissions of non-CO2 forcers, particularly methane (high confidence)."

Chapter 2 concludes: "In 1.5°C-consistent pathways with no or limited overshoot, global net CO2 emissions reach zero around 2050 (2045–2055 interquartile range)." It also states that these pathways are "OS pathways reaching net zero CO2 emissions around 2045–2055 (Table 2.4; Figure 2.5)." The chapter links limiting warming to 1.5°C to stringent limits on cumulative CO2 emissions and the need for net zero followed by net negative CO2 later in the century.

Global net zero CO2 emissions are reached in the early 2050s in modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot, and around the early 2070s in pathways that limit warming to 2°C (>67%). Limiting global warming to 1.5°C with no or limited overshoot implies deep, rapid, and, in most cases, immediate greenhouse gas emissions reductions in all sectors this decade. Projected CO2 emissions reductions are accompanied by a decline in the rate of warming within two decades.

The IEA notes that its updated roadmap "sets out a global pathway to reach net zero CO2 emissions from the energy sector by 2050 and keep the goal of limiting global warming to 1.5 °C within reach." It stresses that "the global pathway to net zero by 2050 we mapped out previously has narrowed, but it is still achievable" and that this pathway is explicitly designed to be compatible with the 1.5°C temperature goal.

AR6 WG1 reiterates the temperature–emissions link: "Global warming of 1.5°C and 2°C will be exceeded during the 21st century unless deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades." It notes that limiting warming to specific levels requires limiting cumulative CO2: "Limiting human-induced global warming requires limiting cumulative CO2 emissions, reaching at least net zero CO2 emissions, along with strong reductions in other greenhouse gas emissions."

The Working Group III contribution to the IPCC’s Sixth Assessment Report assesses mitigation pathways consistent with limiting warming to 1.5°C and 2°C. It finds that global greenhouse gas emissions need to peak between 2020 and at the latest before 2025 in global modelled pathways that limit warming to 1.5°C with no or limited overshoot, and be rapidly reduced thereafter. These pathways typically involve global net zero CO2 emissions in the early 2050s and net zero greenhouse gas emissions thereafter.

While all pathways in the ‘below 1.5°C’ and ‘1.5°C low overshoot’ categories of the Special Report on 1.5°C and category C1 of the AR6 report reach net zero CO2 emissions by mid-century, some do not achieve net zero greenhouse gas emissions in the second half of the century. The AR6 Working Group III has now made net zero greenhouse gases an explicit criterion consistent with Article 4.1 of the Paris Agreement, and established a subcategory C1a, where all pathways achieve net zero greenhouse gas emission around 2070-2075. These pathways also reach net zero CO2 emissions around 2050, in line with the findings of the Special Report on 1.5°C.

The report states: “Mitigation pathways limiting warming to 1.5C with no or limited overshoot reach 50% reductions of CO2 in the 2030s, relative to 2019, then reduce emissions further to reach net-zero CO2 emissions in the 2050s.” Pathways that limit warming to 1.5C with no or limited overshoot (C1) reach net-zero CO2 emissions “between 2050-2055” on average, with a range of between 2035 and 2070 across all the scenarios assessed. Scenarios limiting the world to below 2C generally reach net-zero CO2 in the “early 2070s”, while those limiting warming to 1.5C reach net-zero in the “early 2050s”.

Modelled mitigation pathways that limit warming to 1.5°C (>50%) with no or limited overshoot reach net zero CO2 emissions in the early 2050s and net zero GHG emissions thereafter. Pathways that limit warming to 2°C (>67%) reach net zero CO2 emissions in the early 2070s. These pathways involve rapid and deep and, in most cases, immediate greenhouse gas emissions reductions in all sectors.

The briefing explains: "Regardless of the exact pathway we follow, limiting warming to 1.5°C requires global CO2 emissions to peak in the immediate future, then rapidly decline until they reach net zero around mid-century." It clarifies that "‘Net zero’ indicates that human-caused emissions sources (especially fossil fuels) are strongly reduced and any remaining emissions are balanced with the human-caused removal of CO2 by sinks, for example, through forest management or carbon dioxide removal (CDR) technologies."

The science is clear: limiting warming to 1.5°C above pre-industrial levels requires rapid reduction of greenhouse gas emissions - approximately halving them by 2030 and reaching net-zero soon after mid-century. The analysis notes that reaching net-zero global greenhouse gas emissions in the second half of the century is important to align with Article 4.1 of the Paris Agreement and reduce climate change impacts. It focuses on scenarios that limit warming to 1.5°C with no or low overshoot.

The IPCC’s Special Report on Global Warming of 1.5 °C highlights that the remaining carbon budget consistent with a 50 per cent probability of limiting warming to 1.5 °C was about 580 Gt CO2 from the start of 2018. To avoid warming above these levels, the global energy system will need to transition to net zero CO2 emissions by around 2050 (for 1.5°C) or soon after (for 2°C). Nuclear energy, together with other low carbon energy sources, can provide a substantial contribution to this transition.

The article explains that in pathways that limit warming to 1.5 degrees C with no or limited overshoot, "CO2 emissions would reach net zero by around 2050, before exhausting the carbon budget." It adds that this would concretely involve "phasing out unabated coal use in electricity generation by around 2050 and reducing energy demand" among other measures. The piece summarizes IPCC findings that halving emissions by 2030 and reaching net zero CO2 around mid-century are central to 1.5°C-consistent pathways.

The AR6 Synthesis Report states that in global modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot, global net anthropogenic CO2 emissions decline by about 48% by 2030 relative to 2019 and reach net zero in the early 2050s. It also notes that limiting warming to 1.5°C or 2°C involves rapid, deep and, in most cases, immediate greenhouse gas emissions reductions in all sectors this decade.

World Resources Institute explains that according to the IPCC 1.5°C report, "Annual emissions need to be about half that (25-30 GtCO2e/yr on average) by 2030 to limit warming to 1.5˚C (with no or low overshoot)." It highlights that "Emissions will need to reach net-zero around mid-century. In addition to large emissions cuts in the next decade, net CO2 emissions will on average need to be reduced to zero by mid-century. If the date of reaching net-zero emissions is brought forward one decade to 2040, the chance of limiting warming to 1.5˚C is considerably higher."

The most ambitious pathways fall into a category labelled C1. C1 pathways have a 50% or higher chance of limiting warming to 1.5°C (with no or limited overshoot), as well as around a 90% chance of limiting warming to 2°C, and so meet the Paris Agreement goals on limiting temperature rise. All achieve net zero CO2 emissions around mid-century, with net land-use change and bioenergy with carbon capture and storage acting as sinks to balance out remaining CO2 sources. There is also a subcategory C1a in which emissions of greenhouse gases reach net zero by 2070–2075.

Climate Central, summarizing SR15, notes: "Net CO2 emissions need to drop 45 percent from their 2010 levels by 2030, and reach net-zero by 2050 (meaning that any remaining CO2 emissions would need to be offset by removing carbon dioxide from the atmosphere)." It describes that limiting warming to 1.5°C "requires drastic changes to our energy, transportation, food, and building systems."

Summarising SR15, the slides state: "To limit warming to 1.5°C, CO2 emissions fall by about 45% by 2030 (from 2010 levels)." A separate bullet adds: "To limit warming to 1.5°C, CO2 emissions would need to reach ‘net zero’ around 2050." The presentation emphasises that these conclusions are drawn from the IPCC’s assessment of 1.5°C-consistent pathways.

The piece notes that the 1.5-degree target was set at the Paris climate conference to forestall severe impacts and potential tipping points. It reports that "IPCC scientists have consistently argued that achieving the Paris target will ultimately require some form of negative emissions," meaning that global emissions not only need to fall to net zero but may need to become net negative after mid-century. The article also points out that because of weak action, many scientists now expect the 1.5°C threshold to be at least temporarily overshot.

ClimatePositions quotes the IPCC Summary for Policymakers: "Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching 'net zero' around 2050 (2045–2055 interquartile range)." It further paraphrases: "The IPCC Report ‘Global Warming of 1.5°C‘ released October 2018, finds that limiting global warming to 1.5°C would require reductions of global human-caused CO2 emissions of 45% by 2030 compared to 2010, and reach zero emissions around 2050."

Subsequent to SR15, the IPCC Sixth Assessment Report (AR6) Working Group III (2022) assessed a wider set of scenarios and concluded that pathways limiting warming to 1.5°C (with no or limited overshoot) still typically reach global net zero CO2 emissions around mid-century, though the precise median year can vary slightly (often in the late 2040s or early 2050s) depending on scenario assumptions. AR6 also reinforces that halting warming at any level requires global net CO2 to be reduced to zero and that the timing of net zero is directly related to the temperature limit targeted, because of the near-linear relationship between cumulative CO2 emissions and warming.

Summarizing IPCC findings, the video explains that "this report says that in order to stay under 1.5 degrees the world needs to be emitting overall zero carbon dioxide by around 2050. This would stop the world from warming, but it doesn't guarantee staying under 1.5 degrees. In fact it would give us a 50:50 chance." Later it reiterates: "staying under 1.5 degrees means continuously lowering our emissions until we reach net zero around 2050."

Discussing the Paris Agreement targets, the article states: "The goal: to limit global warming in this century to below 2°C – and preferably to 1.5°C degrees. To do this, countries must reduce their emissions by half by 2030 and reach net-zero by 2050." It notes that halving emissions by 2030 is the "bare minimum" needed to avoid an irreversible vicious cycle and describes net zero as when the amount of greenhouse gas emitted is the same as the amount removed from the atmosphere.