What is 1.5-Degree Pathway?

What is the 1.5-Degree Pathway?

The 1.5-degree pathway refers to the set of emission reduction trajectories consistent with limiting global average temperature increase to 1.5°C above pre-industrial levels — the more ambitious of the two Paris Agreement temperature targets. The IPCC Special Report on 1.5°C (2018) established that reaching this goal requires global CO2 emissions to decline approximately 45% from 2010 levels by 2030 and reach net zero by around 2050. The pathway demands rapid decarbonization across all sectors, supported by carbon dioxide removal to address residual emissions and potential temporary overshoot.

Why It Matters

The difference between 1.5°C and 2°C of warming is not marginal — it's the difference between severe and catastrophic outcomes across multiple dimensions. At 1.5°C, 70–90% of coral reefs die; at 2°C, over 99% are lost. Sea-level rise is 10 cm lower at 1.5°C, reducing the number of people exposed to coastal flooding by 10 million. Arctic ice-free summers occur once per century at 1.5°C versus once per decade at 2°C. Crop yield declines, species extinction rates, and extreme heat exposure all increase dramatically between the two thresholds.

The 1.5°C target has become the benchmark for corporate and financial sector ambition. The Science Based Targets initiative moved to a 1.5°C-only standard in 2022, requiring all new corporate targets to align with the more stringent pathway. Over 7,000 companies across the global economy have committed. The Net Zero Asset Managers initiative, representing $65+ trillion, benchmarks portfolio alignment against 1.5°C. Central banks and regulators use 1.5°C scenarios as the "orderly transition" benchmark in climate stress testing.

The honest assessment as of 2025: the 1.5°C pathway is still physically possible but requires a transformation in the pace and scale of decarbonization that has no historical precedent. Global emissions have not yet peaked. The IEA's Net Zero by 2050 roadmap identifies the technical pathway but notes it requires global clean energy investment to reach $4 trillion annually by 2030 — roughly double current levels. Every year of delay narrows the remaining carbon budget and increases reliance on unproven carbon removal at scale.

The concept of "overshoot and return" has become central to 1.5°C scenarios. Most modeled pathways now assume temporary exceedance of 1.5°C in the 2030s–2040s, followed by net negative emissions that draw temperatures back down. This reliance on future carbon removal carries significant risk — the technologies (direct air capture, enhanced weathering, bioenergy with CCS) are not yet deployed at the required scale, and overshoot may trigger tipping points that are irreversible regardless of later temperature reduction.

How It Works / Key Components

The carbon budget provides the quantitative foundation. The remaining budget for a 50% chance of limiting warming to 1.5°C is approximately 250–400 GtCO2 from 2024. At current emission rates (~40 GtCO2/year from fossil fuels and industry), this budget is exhausted in 6–10 years. The tight budget explains why 1.5°C pathways require immediate, steep emission reductions rather than gradual transitions.

Sector-specific decarbonization pathways define the transformation required. Electricity must reach net-zero emissions by 2035–2040, requiring renewables to grow from roughly 30% to 80%+ of generation while coal is eliminated and gas drastically curtailed. Transport requires rapid electrification — the IEA's 1.5°C pathway envisions 60% of new car sales being electric by 2030 (from roughly 20% in 2024). Industry needs green hydrogen, electrification, CCUS, and circular economy approaches. Buildings require deep efficiency retrofits and electrification of heating. Agriculture and land use must reduce methane and nitrous oxide while protecting and expanding carbon sinks.

Carbon dioxide removal (CDR) plays a necessary but contested role. 1.5°C pathways in the IPCC's database require 5–16 GtCO2/year of CDR by 2050, depending on the speed of emission reductions. Current CDR capacity (excluding conventional afforestation) is roughly 0.01 GtCO2/year. Scaling CDR by three orders of magnitude in 25 years represents an industrial mobilization comparable to the growth of the entire renewables sector. Methods include afforestation/reforestation, biochar, enhanced weathering, direct air capture with carbon storage (DACCS), and bioenergy with carbon capture (BECCS).

The just transition dimension is inseparable from the 1.5°C pathway. Achieving the required transformation at the necessary speed creates enormous distributional challenges — job losses in fossil fuel sectors, energy cost impacts on low-income households, stranded assets in developing economies dependent on fossil fuel revenues. Pathways that ignore equity dimensions face political backlash that slows implementation. The ILO estimates that a 1.5°C-aligned transition could create 24 million new jobs while displacing 6 million — but the geographic and skill mismatches between losses and gains require active management.

The 1.5-Degree Pathway in Practice

Denmark provides one of the clearest national examples of 1.5°C alignment. The country legislated a 70% emission reduction target by 2030 (relative to 1990) — one of the most ambitious near-term goals globally. Implementation includes the world's first energy island (an artificial island hub for 10 GW of offshore wind), a ban on new fossil fuel exploration in the North Sea, mandatory building efficiency standards, and agricultural methane reduction programs. The 2030 target is backed by annual emissions budgets and independent monitoring.

At the corporate level, Maersk's commitment to net-zero shipping by 2040 demonstrates sector-specific 1.5°C alignment in a hard-to-abate industry. The company ordered 19 methanol-fueled container vessels, established green fuel procurement agreements, and developed a roadmap for fleet-wide fuel transition. The specificity — vessel orders, fuel contracts, capital allocation — distinguishes credible 1.5°C alignment from aspirational target-setting.

Council Fire's Approach

Council Fire works with organizations to develop 1.5°C-aligned strategies that are both scientifically credible and operationally feasible. We help clients translate global carbon budgets into sector-specific and company-specific decarbonization roadmaps, with particular attention to ocean-related sectors where blue economy transitions and blue carbon opportunities create pathways that standard frameworks miss. Our stakeholder strategy practice ensures that 1.5°C commitments are communicated with appropriate nuance — acknowledging the challenges and trade-offs rather than offering false simplicity.

Frequently Asked Questions

Has the 1.5°C target already been exceeded?

Global average temperature temporarily exceeded 1.5°C above pre-industrial levels during 2023–2024, driven by long-term warming trends and a strong El Niño. However, the Paris target refers to sustained multi-decadal warming, not individual year exceedances. Climate scientists project that the 1.5°C threshold will be crossed as a multi-year average sometime in the early 2030s. Temporary overshoot followed by return to below 1.5°C through net negative emissions remains theoretically possible but requires unprecedented carbon removal deployment.

What does a 1.5°C pathway mean for fossil fuel production?

The IEA's Net Zero by 2050 scenario — consistent with 1.5°C — requires no new oil and gas field development beyond those already approved as of 2021, and a rapid coal phase-out. Oil demand declines 75% by 2050, gas demand 55%. This has profound implications for fossil fuel companies, producing nations, and financial institutions exposed to these assets. Companies without credible transition plans face stranded asset risk; those developing new fossil fuel resources are making an implicit bet against 1.5°C.

How do carbon offsets and removals fit into the 1.5°C pathway?

The SBTi requires companies to reduce at least 90% of emissions before using carbon removal for the residual 10%. This hierarchy — reduce first, remove residual — is central to 1.5°C pathway credibility. Offsets that avoid or reduce emissions (rather than remove CO2) do not count toward net-zero targets under SBTi or most credible frameworks. The scale of removal needed (5–16 GtCO2/year by 2050) demands massive investment in both nature-based and technological solutions, but these cannot substitute for the steep, near-term emission reductions that define the pathway.