| Key Points |
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Atmospheric carbon dioxide (CO₂) has reached record levels.
The most recent global average CO₂ reading is in the low-to-mid 420s parts per million, well above pre-industrial levels, and the year-to-year rise in 2024 was the largest on record. [1]
Global fossil CO₂ emissions remain near all-time highs at about 37 to 38 gigatonnes per year. [2]
Energy production, industry and transport are the largest human sources, with land-use change and wildfires causing large but variable releases of CO₂. [3]
Natural sinks in the oceans and on land still absorb roughly half of the emissions, but evidence shows a regional weakening under heat and drought stress. [2]
Climate models and current policy pledges indicate a high probability of breaching the 1.5 °C threshold and moving toward 2 °C or more this century, unless emissions decline sharply. [4]
Feedbacks such as permafrost thaw and forest dieback could amplify atmospheric CO₂ and make targets harder to reach. [4]
The technical pathways to limit warming exist, but they require rapid, deep cuts in fossil fuel use, protection and restoration of natural sinks, and substantial carbon removal. [5]
Delays increase the risk of lock-in, stranded assets and irreversible impacts, so near-term action is essential. [4]
Current status & trends
Global mean atmospheric CO₂ reached a new record in 2024 with global averages reported in the low 422–425 ppm range depending on the dataset. [1]
The year-to-year increase recorded between 2023 and 2024 was the largest in the instrumental record at roughly 3.5 to 3.8 ppm. [1]
Pre-industrial CO₂ was about 280 ppm so current levels are roughly 50 percent higher than the baseline used by climate science. [4]
The Global Carbon Project and energy agencies report fossil fuel and cement CO₂ near 37–38 GtCO₂ in 2023–24 with modest growth in 2024. [2]
Annual emissions have not shown a sustained peak and small year-to-year fluctuations mask an upward trend in total atmospheric loading. [2]
Major sources and contributors
The energy sector — power generation and heat — is the largest source of CO₂ from fossil fuels. [3]
Industry, including steel, aluminium and chemical production, and cement, causes a substantial share of emissions. [3]
Transport, particularly road transport and aviation, is another major source and growth area in many regions. [3]
Land-use change, deforestation and large wildfires add pulses of CO₂ and reduce the capacity of ecosystems to store carbon. [2]
China, the United States, the European Union, India and other high-emission economies together account for the bulk of national emissions in absolute terms. [2]
Per-capita emissions remain highest in several wealthy nations and among high-emitting consumers, highlighting equity issues in mitigation. [4]
Oceans and terrestrial ecosystems currently absorb around half of human emissions, but their efficacy varies year to year and can decline under heat and drought stress. [2]
Impacts across domains
Higher CO₂ and the resulting warming increase heat-related illness, respiratory disease from wildfires, and infectious disease risk in some regions. [4]
Climate change amplifies displacement and migration pressure where livelihoods and water supplies are undermined. [4]
Economies face rising costs from extreme events, lost labour productivity, infrastructure damage and higher insurance premiums. [4]
Ecological impacts include range shifts, coral bleaching from warmer and acidifying oceans, and increasing extinction risks for sensitive species. [4]
Politically, failure to cut emissions intensifies diplomatic tension, complicates development and raises governance challenges for adaptation finance. [4]
Culturally, Indigenous peoples and local communities experience loss of land and traditions, while climate change becomes a growing theme in art, law and public debate. [4]
Projections and long-term implications
IPCC-class climate models indicate that, under current policies, global warming is likely to exceed 1.5 °C this decade and move toward or beyond 2 °C by 2100. [4]
Remaining carbon budgets for a two-thirds chance of 1.5 °C are small and require rapid deep cuts in CO₂ emissions this decade. [4]
Feedbacks such as permafrost carbon release, forest dieback and reduced ocean uptake could add several hundred million tonnes to future CO₂ and amplify warming. [4]
Scenarios range from business-as-usual with rising emissions to rapid decarbonisation with net-zero around mid-century and substantial negative emissions thereafter. [5]
Urgency, feasibility and timing for reduction
To limit warming to near 1.5 °C global CO₂ emissions must fall sharply and reach net zero roughly by mid-century with rapid declines by 2030. [4]
Reducing atmospheric CO₂ concentrations as well as emissions matters because current CO₂ will persist and continue to drive warming for centuries. [4]
High-impact interventions include phasing out unabated coal, halting new oil and gas infrastructure, electrifying transport, decarbonising industry and scaling nature-based protection. [5]
Carbon dioxide removal (CDR) technologies and restored ecosystems can help manage residual emissions but they face cost, scale and governance constraints. [5]
Delays increase entropy in the energy system, cost more to reverse, and raise the chance of passing irreversible ecological thresholds. [4]
Conclusion and recommended priorities
The empirical evidence is clear: CO₂ is at record levels, emissions remain near all-time highs and natural sinks are under stress. [1]
Priority actions are immediate and deep cuts to fossil fuel use, protection and restoration of forests and soils, rapid electrification and investment in proven removal where needed. [5]
Policymakers must couple emissions targets with concrete sectoral plans, finance for the global south and just transitions for workers and communities. [4]
Delaying action raises costs and risk and reduces options; the mission to reduce CO₂ is urgent and feasible if nations act at scale now. [4]
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