How Much Warming Really Comes With Carbon 350, 450, 550, or 700 ppm? Here is Your Plain-English Climate Guide. Unfortunately, it's going to be a shocker when you discover the difference between what your government says about our current and future global warming and what it will actually be. The article covers everything you need to know about already-committed future global warming vs. the warming you see today.
Quick navigation
- Executive summary
- What this page does
- Adjusted method
- Baseline CO₂ chart
- Baseline CO₂e chart
- Adjusted CO₂ chart
- Adjusted CO₂e chart
- Side-by-side comparison table
- Why the adjusted charts are higher
- What this page does not show
- FAQ
- References
- Baseline method
Executive summary
A quick terminology fix: people often say “carbon ppm,” but the atmospheric concentration metric here is CO₂ in parts per million. This page also shows CO₂E charts, which are a forcing-equivalent shorthand for the total global warming effect of the major long-lived greenhouse gases, such as carbon dioxide, methane, and nitrous oxide. Although less well known to the public, CO₂E is a more comprehensive and useful metric for forecasting future average global temperatures driven by fossil-fuel pollution in our atmosphere.
Here are two additional definitions you will also need to have clear in your mind as you read this committed global warming article.
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- Committed global warming: the future warming already locked in by greenhouse gases already in the atmosphere, even if emissions stop or change little right away. The full commitment to the final global warming temperature at any given carbon level you currently see could take 20 or even 30 years to reach. (In the FAQ near the bottom of the page is a larger explanation of the numerous dynamics behind what causes the long delays of committed yet unrealized global warming.)
- Equilibrium global warming: the full long-term temperature rise Earth reaches after the climate system has fully adjusted to a given greenhouse gas level.
The plain-English difference is: equilibrium is the final settled temperature, while committed is the warming already baked in on the way to its final committed temperature level.
What this means and why it is so important is because everyone who hears tht a particular carbon level in parts per million (ppm) has been reached, like our march of 2026 current 429 to 431 carbon PPM level also believe that our current average global temperature over pre-industrial levels is now about 1.7°C but that is not it's true eventual temperaturelevel just from the 429 to 431 carbon level.
That's why we have created this article to show you what the real danger is that is already committed or baked into future temperature increases at current relevant carbon dioxide (CO2 levels or CO2 EQ levels.
There is little doubt that some of you will be shocked when you look at the charts below, which illustrate the current IPCC calculations and our adjusted calculations, highlighting the well-known underestimation in the IPCC's calculations. You do not have to be a science person to simply look at the various tables and charts below and see what the low medium and high predictions are under various scenarios.
Even in the most conservative scenarios, they are not looking good. When you look at the adjusted forecast further down the page, there is real incentive to get our governments to act and to begin our own preparations for the consequences we can no longer avoid.
About the average global temperature forecast charts below:
The first pair of charts below uses a mainstream baseline built from the IPCC-style logarithmic concentration-warming relationship and the AR6 likely range for equilibrium climate sensitivity of 2.5°C to 4.0°C per doubled CO₂, with a central estimate of 3.0°C.
The second pair uses an adjusted higher-risk scenario built from Hansen's 4.8°C ± 1.2°C fast-feedback ECS, a separate aerosol-masking add-on, and a transparent 6% uplift for the many IPCC underestimated climate change tipping points, feedback loops, and nonlinear effects. (Please see this underestimation article that explains this dangerous underestimation of public statements on the climate change emergency by the IPCC.)
What this page does for understanding current and future climate change temperatures
This page is built to do something unusually useful in climate communication: it puts the mainstream baseline temperature predictions and the higher-risk, adjusted-scenario temperature predictions on the same page, so readers can compare them without pretending they use the same method. From this comparison and understanding, individuals, businesses, and nations can make better decisions about their climate change future and what they need to do to prepare for it.
The Mainstream baseline section below sees the familiar IPCC-style fast-feedback equilibrium framework. It is conservative relative to higher-end interpretations because it does not add a separate aerosol loss term or an explicit nonlinear-feedback uplift.
The Adjusted higher-risk section uses Hansen's higher fast-feedback ECS, adds an explicit aerosol-masking term, and then applies a transparent 6% scenario uplift. That makes it useful for readers who think the mainstream framing is missing too much of the danger, which, to be fair, is not exactly an exotic suspicion anymore. Important honesty clause: the adjusted charts are scenario graphics, not a formal IPCC consensus figure. The 6% uplift is a transparent design choice for this version. The aerosol term is also policy-sensitive because aerosol masking depends on pollution controls and sulfur emissions, not just on greenhouse-gas concentration. For the hard science people, we have moved the baseline method and the assumptions we used to the end of the page
Baseline chart 1: CO₂ concentration and eventual equilibrium warming
This chart shows the likely equilibrium warming range associated with different CO2 concentrations alone, from 350 ppm to 1000 ppm. The shaded band uses the IPCC AR6 likely range for equilibrium climate sensitivity, 2.5°C to 4.0°C per CO2 doubling. The dark line uses the commonly used central estimate of 3.0°C per doubling.
Interpretation: if the atmosphere were somehow held at one of these concentration levels long enough for the climate system to settle toward equilibrium, the eventual global-average warming would likely fall within the indicated range or band. The planet, tragically, does not care whether a politician finds that inconvenient.
| CO2 level | Likely equilibrium warming range | Central estimate | Quick reading |
|---|---|---|---|
| 350 | 0.8°C to 1.3°C | 1.0°C | |
| 400 | 1.3°C to 2.1°C | 1.6°C | |
| 450 | 1.7°C to 2.8°C | 2.1°C | Near current-risk debate territory |
| 500 | 2.1°C to 3.4°C | 2.5°C | |
| 550 | 2.5°C to 3.9°C | 3.0°C | |
| 600 | 2.8°C to 4.4°C | 3.3°C | |
| 650 | 3.1°C to 4.9°C | 3.7°C | |
| 700 | 3.3°C to 5.3°C | 4.0°C | |
| 800 | 3.8°C to 6.1°C | 4.6°C | |
| 900 | 4.2°C to 6.8°C | 5.1°C | |
| 1000 | 4.6°C to 7.4°C | 5.5°C |
Baseline chart 2: CO₂-equivalent concentration and eventual equilibrium warming
CO2e, or CO2-equivalent, converts the combined warming effect of multiple greenhouse gases into the concentration of CO2 that would produce a similar radiative forcing. On this page, the current headline CO2e value is NOAA’s long-lived greenhouse gas CO2e number, not an all-forcing metric that also includes short-lived cooling aerosols.
The chart below uses the same concentration-warming relationship as the CO2 chart, but it also overlays the classic IPCC stabilization categories I through VI used in AR4. That gives both a continuous public guide and a direct link back to a long-cited IPCC concentration framework.
| IPCC stabilization category | CO2e concentration band | Equilibrium warming band above pre-industrial | Plain-English reading |
|---|---|---|---|
| I | 445-490 ppm CO2e | 2.0-2.4°C | Lowest AR4 stabilization category assessed here |
| II | 490-535 ppm CO2e | 2.4-2.8°C | Roughly late-2°C to high-2°C equilibrium band |
| III | 535-590 ppm CO2e | 2.8-3.2°C | Crosses into low-3°C territory |
| IV | 590-710 ppm CO2e | 3.2-4.0°C | Roughly low-3°C to 4°C equilibrium band |
| V | 710-855 ppm CO2e | 4.0-4.9°C | Around 4°C to just under 5°C equilibrium band |
| VI | 855-1130 ppm CO2e | 4.9-6.1°C | About 5°C to 6°C+ equilibrium band |
Those category ranges come directly from the IPCC AR4 mitigation assessment. The chart itself uses the same logarithmic concentration-warming relationship, while the table preserves the original IPCC category bins because those still show up all over climate discussions, policy papers, and public arguments.
Adjusted chart 1: CO₂ concentration with Hansen ECS, aerosol add-on, and nonlinear uplift
Adjusted CO₂ chart, 350 ppm to 800 ppm
Range combines Hansen fast-feedback ECS, a separate aerosol-masking add-on, and the user-specified 6% nonlinear-feedback uplift.
At today's 2024 global average CO₂ level of 422.8 ppm, this adjusted scenario produces a range of roughly 3.3°C to 6.4°C of eventual committed warming above preindustrial, with a midpoint near 4.8 °C.
Please keep in mind that in 2024, we were at 422.8 CO2 PPM, and that this will eventually produce temperatures well beyond what we're being told (3.3°C to 6.4°C) when you adjust for IPCC underestimation factors. If our Job One adjusted forecasting is even close to accurate, humanity faces the worst possible climate change nightmare.
| CO₂ concentration | Low adjusted range | Midpoint | High adjusted range |
|---|---|---|---|
| 350 | 2.3°C | 3.5°C | 4.6°C |
| 375 | 2.6°C | 4.0°C | 5.3°C |
| 400 | 3.0°C | 4.4°C | 5.9°C |
| 425 | 3.3°C | 4.9°C | 6.4°C |
| 450 | 3.7°C | 5.3°C | 7.0°C |
| 500 | 4.2°C | 6.1°C | 7.9°C |
| 550 | 4.8°C | 6.8°C | 8.8°C |
| 600 | 5.2°C | 7.4°C | 9.6°C |
| 650 | 5.7°C | 8.0°C | 10.3°C |
| 700 | 6.1°C | 8.5°C | 11.0°C |
| 750 | 6.5°C | 9.1°C | 11.6°C |
| 800 | 6.8°C | 9.5°C | 12.2°C |
Reading note: these are long-run committed-warming scenario values. They are not the same thing as the warming already fully realized at the surface today.
Adjusted chart 2: CO₂-equivalent concentration with Hansen ECS, aerosol add-on, and nonlinear uplift
Adjusted CO₂-equivalent chart, 350 ppm to 800 ppm
CO₂e here is treated as a forcing-equivalent concentration. NOAA's AGGI value is for long-lived greenhouse gases, with aerosols handled separately in the add-on.
At NOAA's 2024 long-lived greenhouse-gas CO₂-equivalent level of 539 ppm, this adjusted scenario produces a range of roughly 4.6°C to 8.6°C of eventual committed warming above preindustrial, with a midpoint near 6.6°C. Please keep in mind that in 2024, we were at 539 CO2-equivalent PPM, which will eventually produce temperatures (4.6°C to 8.6°C) well beyond what we're being told when you adjust for IPCC underestimation factors. If our adjusted forecasting at this next level of IPCC correction is even close to accurate, humanity faces the worst possible climate change nightmare.
| CO₂e concentration | Low adjusted range | Midpoint | High adjusted range |
|---|---|---|---|
| 350 | 2.3°C | 3.5°C | 4.6°C |
| 375 | 2.6°C | 4.0°C | 5.3°C |
| 400 | 3.0°C | 4.4°C | 5.9°C |
| 425 | 3.3°C | 4.9°C | 6.4°C |
| 450 | 3.7°C | 5.3°C | 7.0°C |
| 500 | 4.2°C | 6.1°C | 7.9°C |
| 539 | 4.6°C | 6.6°C | 8.6°C |
| 550 | 4.8°C | 6.8°C | 8.8°C |
| 600 | 5.2°C | 7.4°C | 9.6°C |
| 650 | 5.7°C | 8.0°C | 10.3°C |
| 700 | 6.1°C | 8.5°C | 11.0°C |
| 800 | 6.8°C | 9.5°C | 12.2°C |
Because CO₂e already folds in the forcing of long-lived non-CO₂ greenhouse gases, the CO₂e chart is useful for showing the broader greenhouse load. But it still does not fold in aerosol cooling, which is why the separate aerosol term remains necessary in this scenario design. When you add in that the missing aerosol factor, which could add one 1/4 to 1/2 degree Celsius to average global temperatures once those aerosols are eliminated in the far distant future, when temperatures are already near or beyond human tolerance, you have a real additional problem.
Side-by-side comparison table
This table gives readers the cleanest possible comparison between the two frameworks. Same concentration, different assumptions, very different eventual temperature commitment. Climate communication would be less broken if more articles did exactly this.
| Concentration | Baseline range | Baseline midpoint | Adjusted range | Adjusted midpoint |
|---|---|---|---|---|
| 350 | 0.8°C to 1.3°C | 1.0°C | 2.3°C to 4.6°C | 3.5°C |
| 400 | 1.3°C to 2.1°C | 1.5°C | 3.0°C to 5.9°C | 4.4°C |
| 422.8 | 1.5°C to 2.4°C | 1.8°C | 3.3°C to 6.4°C | 4.8°C |
| 450 | 1.7°C to 2.7°C | 2.1°C | 3.7°C to 7.0°C | 5.3°C |
| 500 | 2.1°C to 3.3°C | 2.5°C | 4.2°C to 7.9°C | 6.1°C |
| 539 | 2.4°C to 3.8°C | 2.8°C | 4.6°C to 8.6°C | 6.6°C |
| 600 | 2.7°C to 4.4°C | 3.3°C | 5.2°C to 9.6°C | 7.4°C |
| 700 | 3.3°C to 5.3°C | 4.0°C | 6.1°C to 11.0°C | 8.5°C |
| 800 | 3.8°C to 6.1°C | 4.5°C | 6.8°C to 12.2°C | 9.5°C |
The baseline and adjusted formulas are applied the same way to both CO₂ and CO₂e concentration values. The interpretive difference is that CO₂ is one gas, while CO₂e is a forcing-equivalent shorthand for multiple long-lived greenhouse gases.
Why are the adjusted charts higher than what the IPCC usually shows
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- Higher climate sensitivity: the adjusted charts replace the IPCC AR6 best estimate of 3.0°C per doubling with Hansen's 4.8°C ± 1.2°C estimate.
- Aerosol masking is handled explicitly: the adjusted charts add warming that could emerge if aerosol cooling weakens or is removed. The baseline charts do not do that.
- Transparent nonlinear uplift: the adjusted charts apply a flat 6% uplift to tipping points, feedback loops, and nonlinear reactions that were underestimated or not included in IPCC calculations. That coefficient is shown openly rather than smuggled in as fake certainty.
- Same concentration, different risk framing: the baseline charts ask, “What does the standard fast-feedback equilibrium relationship imply?” The adjusted charts ask, “What if sensitivity is higher and several omitted risks matter more than mainstream invested interest censored public graphics usually admit?”
What this page does not show
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- It does not show the temperature in 2100. These are eventual equilibrium or committed-warming graphics, not century-end forecasts.
- It does not prove that one method is the single final truth. It gives readers two transparent frameworks, one mainstream and one IPCC underestimation-adjusted.
- It does not turn CO₂ and CO₂e into identical concepts. They answer related but different questions.
- It does not settle Earth-system sensitivity debates. The adjusted charts are still fast-feedback charts with explicit scenario add-ons, not full Earth-system sensitivity reconstructions.
FAQ
Does this page present a single settled scientific answer?
No. It shows two frameworks side by side: a mainstream baseline and a higher-risk adjusted scenario. That is the point. Blending them into one hidden method would be less honest.
Why are the adjusted charts so much higher?
Because they combine three upward moves: a higher ECS, a separate aerosol-masking term, and a 6% nonlinear-feedback uplift.
Why keep the baseline charts if you think the adjusted ones may matter more?
Because the baseline charts, unfortunately, remain the mainstream starting point, most readers need to see the conservative frame before they can understand why more climate change scientists and analysts argue that the real risk is significantly higher.
Does NOAA's CO₂-equivalent number already include aerosol cooling?
No. NOAA's AGGI CO₂e number is for long-lived greenhouse gases. Aerosol cooling is a separate forcing category and is not already baked into that number.
Are these 2100 forecasts?
No. They are long-run commitment graphics. The oceans delay part of the response, so equilibrium warming, committed warming, and end-of-century warming are not the same thing. (See next question.)
What are the causes of dynamics behind the committed global warming process, which caused a final average global temperature to occur as much as 20 to 30 years later than when a certain carbon dioxide (CO2 or CO2 EQ level has been reached?
The main reason final temperatures are delayed is that the oceans absorb huge amounts of heat and warm up slowly. Earth’s climate is like a giant pot of water on a stove: even after the flame is turned up, the water takes time to fully heat. A few main forces create that delay:
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- Ocean heat uptake: the oceans soak up excess heat and release it slowly over decades to centuries.
- Ice melt and big system changes: ice sheets, glaciers, forests, and permafrost do not change instantly, so their warming effects build over time.
- Long-lived greenhouse gases: carbon dioxide stays in the atmosphere for a very long time, so its heating effect continues long after it is emitted.
- Climate feedbacks: as warming increases, it can trigger additional changes, such as less reflective ice, more water vapor, and methane release, which can further amplify warming.
So committed global warming means this: the heating has already been set in motion, but the climate system takes a long time to fully catch up. Human civilization, naturally, has built itself within a system with delayed consequences and then acted surprised by them.
References
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IPCC AR6 Working Group I, Chapter 7. Summary assessment of equilibrium climate sensitivity, including a best estimate of 3°C and a likely range of 2.5°C to 4.0°C .
https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-7/ -
Hansen et al. (2023), Global warming in the pipeline. Used here for the fast-feedback ECS estimate of 4.8°C ± 1.2°C for doubled CO₂, and for the argument that aerosol forcing may be more negative than the IPCC best estimate.
https://academic.oup.com/oocc/article/3/1/kgad008/7335889 -
NOAA Annual Greenhouse Gas Index (AGGI). Used here for the 2024 long-lived greenhouse-gas CO₂-equivalent value of 539 ppm , of which 422.8 ppm was CO₂.
https://gml.noaa.gov/aggi/ -
NOAA Climate.gov, atmospheric carbon dioxide update. Used here as a public-facing current reference for global atmospheric CO₂ levels.
https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide -
IPCC AR4 Working Group III, Summary for Policymakers, Figure SPM.8. Used here for the classic relationship between stabilization levels in ppm CO₂-eq and equilibrium global mean temperature increase, with a central line based on 3°C climate sensitivity and a shaded range between 2°C and 4.5°C.
https://www.ipcc.ch/site/assets/uploads/2018/03/ar4-wg3-spm.pdf -
National Academies, Climate Stabilization Targets. Used here for the note that equilibrium temperature entries were computed by logarithmic extrapolation from climate sensitivity values.
https://www.nationalacademies.org/read/12877/chapter/9
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IPCC AR6 Working Group I, Chapter 7. Summary assessment of equilibrium climate sensitivity, including a best estimate of 3°C and a likely range of 2.5°C to 4.0°C .
Baseline calculation method and assumptions
Source note: The four charts on this page are original explanatory graphics built from the methods and source values listed below. They are designed for public understanding of how big the problem really is with the IPCC's and our governments' underestimation of current climate consequences, time frames, and solutions. Please see this article on the dangerous underestimation found in many public statements on the climate change emergency by the IPCC.
This baseline calculations section uses the standard fast-feedback concentration-warming relationship:
T
eq
≈ ECS × ln(C / 280) / ln(2)
Where T eq is eventual equilibrium warming above preindustrial, ECS is equilibrium climate sensitivity, and C is atmospheric concentration in ppm or ppm CO₂e. For the baseline range, this page uses 2.5°C to 4.0°C per doubling, with a 3.0°C midpoint. The baseline CO₂e chart also preserves the classic IPCC AR4 stabilization categories so readers can tie the continuous chart back to a long-cited IPCC framework.
Adjusted calculation method and assumptions
Base concentration-response relationship: The adjusted charts still use the same logarithmic concentration structure, but they use higher sensitivity and include terms omitted from the baseline chart.
Base adjusted temperature range = (3.6°C to 6.0°C) × log₂(concentration / 280)
Why 3.6°C to 6.0°C per doubling? Because this version uses Hansen's 4.8°C ± 1.2°C fast-feedback ECS estimate instead of the IPCC AR6 best estimate of 3.0°C.
Aerosol-masking add-on. Aerosol cooling is treated separately. Using Hansen's sensitivity framing of 1.2 ± 0.3°C per W/m² , aerosol forcing values of roughly -1.09 W/m² and -1.63 W/m² translate into an added warming range of roughly +0.98°C to +2.45°C.
Adjusted low = 1.06 × [3.6 × log₂(concentration / 280) + 0.98] Adjusted high = 1.06 × [6.0 × log₂(concentration / 280) + 2.45]
CO₂e note: NOAA's AGGI CO₂e value is a long-lived greenhouse-gas equivalent concentration. It does not already include aerosol cooling, so the aerosol term is added separately on the adjusted CO₂e chart. That is why the adjusted CO₂e chart is not double-counting the same thing.
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