Scan: How bad will CO2 atmospheric concentration get before 2030? — At least 450

date	predicted	market price	confidence
2026-08-29	2%	13%	90%
2026-08-22	3%	21%	82%
2026-08-15	2%	21%	85%

1. Planner Fable 5.1 · Fermi decomposition + tool plan

Tools chosen: kalshi_direct kalshi_related polymarket_related claude_news gdelt_news wikipedia code_execution

Sub-questions (Fermi decomposition)

Which CO2 data series and aggregation (Mauna Loa monthly mean, daily mean, hourly, or NOAA global mean) does the Kalshi KXCO2LEVEL-30 market use for resolution, and does a single daily/hourly reading of 450 count?
What is the most recent Mauna Loa monthly mean CO2 and the 2025 seasonal peak (May) value?
What has the annual CO2 growth rate been over the last 5-10 years, and what was the maximum single-year increase on record (e.g., 2023-2024 El Niño)?
What is the highest daily or hourly CO2 reading ever recorded at Mauna Loa relative to the monthly mean, i.e., how large are short-term excursions above the seasonal peak?
Under trend, accelerated (e.g., 3.5-4 ppm/yr), and extreme growth scenarios, what monthly-mean peak would be reached by May 2029 and December 2029?
How is Kalshi pricing the other thresholds in KXCO2LEVEL-30 (e.g., 435, 440, 445), and are the prices internally consistent with a ~2.5-3 ppm/yr trend?

Planner reasoning

Resolution hinges on the exact CO2 metric Kalshi uses (Mauna Loa monthly mean vs. daily/hourly readings vs. NOAA global mean) and whether trend growth (~2.5-3 ppm/yr from ~425-430 ppm in 2025) can plausibly reach 450 by Dec 2029. Under any monthly-mean series this looks very unlikely (~440-445 peak by May 2029), so the key research is confirming the current level, growth-rate distribution (El Niño spikes), the data source in the rules, and how the market is pricing sibling thresholds.

2. Research Parallel tool calls

tool	status	time	items	summary
kalshi_direct	OK	0.2s	1	## This Market's Kalshi Data At least 450 (KXCO2LEVEL-30-450) - Current price (probability): 13.00% - 7-day price change: -8.00% - 30-day price change: -1.00% - Average daily volume: 26 contracts - Price range: 12.00% - 22.00% - Data points: 27 days
kalshi_related	OK	3.4s	2	2 related markets / summaries. series KXCO2LEVEL: 0 markets (skipped 5 no-signal) \| keyword 'CO2': ok \| keyword 'carbon dioxide': no matches \| keyword 'climate': ok
polymarket_related	OK	3.4s	0	Scanned 100 active Polymarket markets, kept 0 matches. keyword 'CO2': 0 markets \| keyword 'carbon dioxide ppm': 0 markets \| keyword 'Mauna Loa': 0 markets
claude_news	OK	25.6s	15	Key findings on atmospheric CO2 (Mauna Loa) relevant to "≥450 ppm before 2030": - Current level (2025 seasonal peak): For the first time, the seasonal peak of carbon dioxide concentrations in the atmosphere exceeded 430 parts per million (ppm) at NOAA's Mauna Loa Observatory on Hawaii in 2
gdelt_news	OK	177.6s	10	GDELT: 10 articles across 3 queries (lookback=180d). 'Mauna Loa CO2 ppm record': error GDELT rate-limited after retries (429) \| 'atmospheric carbon dioxide 2025 peak': error GDELT rate-limited after retries (429) \| 'CO2 growth rate NOAA': 10 hits
wikipedia	OK	3.5s	3	Fetched 3 Wikipedia entries (0 missing pages).
code_execution	OK	73.5s	0	Monte Carlo CO2 Projection Results (10,000 paths, AR(1) growth ρ=0.5, El Niño spike overlay, seasonal ±3.5 ppm cycle) - P(any monthly mean ≥ 450 ppm by Dec 2029): ~0.0% — the simulated monthly-mean maximum (across all 60 months, all paths) tops out around 444.9 ppm (p90) and never reaches 4

3. Evidence Brief Sonnet 5 · 6044 chars

# Current state Kalshi's KXCO2LEVEL-30-450 asks whether atmospheric CO2 reaches ≥450 ppm before Jan 2030. Current Mauna Loa readings are in the 429-432 ppm range (2025 seasonal peak); reaching 450 ppm monthly-mean by 2029 would require growth far beyond any historical rate. Market currently prices this at 13% YES, having drifted down from a 22% high over the past 30 days. # Timeline of key events - 2020: Annual average CO2 413.94 ppm (Scripps); annual rise 2.51-2.58 ppm (confirmed, metoffice.gov.uk). - 2023: May peak +3.0 ppm YoY (confirmed, NOAA). - 2024-05: May peak 426.90 ppm, +2.9 ppm YoY, 5th-largest annual growth in 50-yr NOAA record; 2023-2024 combined largest two-year jump on record (confirmed, noaa.gov). - 2024 (full year): Annual average at Mauna Loa 424.61 ppm (record); global average 422.7 ppm, +3.75 ppm YoY — largest one-year increase on record (confirmed, climate.gov). - 2025-04: Monthly average 429.64 ppm (confirmed, NOAA GML). - 2025-05: Seasonal peak exceeds 430 ppm for first time; Scripps 430.2 ppm (+3.5 ppm YoY), NOAA 430.5 ppm (+3.6 ppm YoY) (confirmed, scripps.ucsd.edu / NOAA). - Met Office forecast: 2026 May peak predicted at 432.2 ± 0.6 ppm (reported/modeled, metoffice.gov.uk). - Wikipedia (2026 snapshot): concentration reached "432 ppm" in 2026 (reported, low-confidence secondary source, consistent with trend). # Event Will atmospheric CO2 concentration reach at least 450 ppm before January 2030 (KXCO2LEVEL-30-450)? # Outcomes to forecast Yes / No # Kalshi market anchor **YES = 13%** (current). 7-day change: -8pts; 30-day change: -1pt. Price range over 27 days: 12%-22%. Average daily volume: 26 contracts (thin/illiquid market). # Sub-question answers 1. **Data series used for resolution** — Not explicitly confirmed in Kalshi rules text (none provided). Research strongly infers NOAA/Scripps Mauna Loa *monthly mean* (the standard public "Trends in CO2" series) is the likely reference, not a single daily/hourly spike [claude_news]. This is a key unknown—if daily/hourly readings count, odds rise meaningfully (see Q4). 2. **Most recent monthly mean / 2025 peak** — April 2025: 429.64 ppm; May 2025 seasonal peak: 430.2 ppm (Scripps) / 430.5 ppm (NOAA) [claude_news, scripps.ucsd.edu]. 3. **Recent annual growth rate** — ~2.5 ppm/yr (2019-2020) accelerating to 3.5-3.75 ppm/yr (2023-2024), with 2024's 3.75 ppm the largest one-year increase on record [climate.gov, noaa.gov]. 4. **Daily/hourly excursions above monthly mean** — Not directly quantified in raw sources, but Monte Carlo modeling estimates daily noise of ~±2 ppm sd around monthly trend, enabling occasional daily spikes several ppm above the monthly mean during peak season [code_execution]. 5. **Projected peaks under scenarios** — Monte Carlo (10,000 paths, ~2.7 ppm/yr mean growth): May 2029 monthly-mean peak ≈ 442.5 ppm (90% CI 439.3-445.5); Dec 2029 annual mean ≈ 438.1 ppm (90% CI 435.1-440.9) [code_execution]. Even p99+ tail stays below ~447 ppm on monthly-mean basis. 6. **Kalshi pricing of other thresholds (435/440/445)** — Not returned in kalshi_related search (only the 450 contract and unrelated climate-goal markets surfaced); cannot assess internal consistency across the ladder from available data. # Key facts (high-confidence, factual) 1. [NOAA/Scripps] 2025 May seasonal peak: 430.2-430.5 ppm. 2. [climate.gov] 2024 annual average: 424.61 ppm (Mauna Loa); global 422.7 ppm, record +3.75 ppm YoY. 3. [NOAA] 2022-2024 saw largest two-year May-peak jump in 50-yr record (~5.9 ppm combined). 4. [code_execution] Monte Carlo simulation: P(monthly mean ≥450 ppm by Dec 2029) <0.1%; P(any daily reading ≥450 ppm) ≈9%. 5. [Wikipedia] Present CO2 level is highest in ~14 million years (per updated Wikipedia sourcing) / Met Office says highest in 2+ million years. # Cross-market signals - Kalshi related: No 435/440/445 rungs surfaced; other Kalshi climate-goal markets (EU/India/US) show unrelated pricing, no arbitrage signal. - Polymarket: Zero matching markets found (no CO2/ppm/Mauna Loa markets exist there) — no cross-check available. - Sportsbook implied: N/A (not applicable to this event type). # Analyst opinions and speculation - claude_news synthesis: reaching 450 ppm by 2030 "highly unlikely," would require 6-8 ppm/yr sustained growth — nearly double the current record rate. - Scientists (NOAA/UC) emphasize record-fast recent growth as alarming, but no source suggests trajectory nearing 450 ppm by 2030. - Met Office's dynamic 2026 forecast (432.2 ppm May peak) implies straight-line continuation, far below 450. # Directional lean per outcome - **YES (≥450 by 2030):** Opposing evidence dominates — current trajectory (~429-431 ppm in 2025) with even accelerated 3.5-3.75 ppm/yr growth reaches only ~442-448 ppm by 2029 peak under Monte Carlo modeling; would need unprecedented near-doubling of record growth rate. Only plausible path is if resolution counts transient daily/hourly spikes (~9% modeled probability), which is uncertain and likely not the intended resolution basis. - **NO:** Strongly favored — supported by consistent multi-source trend data (NOAA, Scripps, Met Office, Monte Carlo), all converging on a 2029 peak in the low-to-mid 440s ppm range, well under 450. # Gaps / unknowns - Exact Kalshi resolution source/methodology (monthly vs. daily vs. hourly) not confirmed — this is the single biggest swing factor. - No visibility into Kalshi's other threshold rungs (435/440/445) to cross-validate implied market curve. - No Polymarket or sportsbook cross-market data available. # Calibration anchors - Kalshi current YES price: **13%** (down from 22% high; declining trend suggests market increasingly confident in NO). - Quantitative model (Monte Carlo, monthly-mean basis): <0.1% probability of YES — implies market's 13% may be overpriced relative to strict monthly-mean resolution, unless daily-reading ambiguity is priced in. - Historical precedent: no year-over-year jump has ever approached the ~5-6 ppm/yr pace needed sustained through 2029 to hit 450 ppm.

4. Forecasters Fable 5.1 + GPT-5.6 Sol · in parallel

claude-fable-5-1

78% conf

Yes	5%
No	95%

The 2025 seasonal peak was ~430.5 ppm (NOAA/Scripps) and the Met Office projects a 2026 peak of ~432.2 ppm; reaching 450 ppm by the May 2029 peak requires ~4.9-5.5 ppm/yr sustained, well above the record 3.75 ppm/yr set in 2024. The brief's Monte Carlo puts the May 2029 monthly-mean peak at ~442.5 ppm (90% CI 439-445.5) with <0.1% chance of a monthly mean ≥450, and the most likely resolution source is the NOAA Mauna Loa monthly series. The only meaningful YES path is ambiguity about daily/hourly spikes counting, which is unconfirmed and still requires a multi-sigma excursion. Kalshi's 13% anchor is in a thin, long-dated market where tail YES prices are typically inflated by capital costs; I discount below it but keep some weight for resolution-methodology ambiguity and a possible strong El Niño-driven acceleration.

gpt-5.6-sol

67% conf

Yes	8%
No	92%

The Kalshi anchor is 13% YES, but NOAA and Scripps place the 2025 seasonal peak at only 430.2-430.5 ppm, while the Met Office projects about 432.2 ppm in May 2026. Recent growth has accelerated, yet reaching 450 ppm by 2029 would still require sustained increases well beyond historical records; the monthly-mean simulation assigns less than 0.1% to that outcome and projects a 2029 peak near 442.5 ppm. Daily variability creates a plausible tail, with modeling estimating roughly a 9% chance of some daily reading reaching 450 ppm. Because the unspecified resolution methodology could count such transient readings, YES remains meaningful, but the strong trend evidence warrants moving below the 13% market price.

5. Devil's Advocate Sonnet 5 · red-team critique

Both forecasts converge tightly (5% and 8%) around a weighted blend of the <0.1% monthly-mean probability and the ~9% daily-spike probability, but neither explicitly shows their weighting math—it's unclear why Forecast 1 lands at 5% (implying <50% weight on daily-reading resolution) versus Forecast 2's 8% (implying nearly full weight on the 9% daily-spike scenario), given they cite identical evidence.

Neither forecast grapples with the fact that if resolution is confirmed as monthly-mean (the stated "likely" basis), the honest probability should be far below even 5%—closer to the modeled <0.1%—so their final numbers appear anchored more to splitting the difference with Kalshi's 13% than to the model's actual tail estimate.

Both forecasts ignore the possibility of a structural growth-rate acceleration (e.g., permafrost carbon feedback, Amazon dieback, or a major wildfire/El Niño supercycle) that could push the underlying trend rate itself upward rather than just adding noise around a fixed ~2.7 ppm/yr mean—the Monte Carlo model assumes a stationary growth distribution, which both forecasters treat as ground truth without noting this key model risk.

The 30-day price drift (22% → 13%, with a sharp -8pt move in just 7 days) suggests informed traders may have recently obtained clarity on resolution methodology (e.g., ruling out daily spikes), which neither forecast investigates as a potential explanation for why the market itself is converging toward the low quantitative estimate rather than staying anchored near a daily-spike-inclusive probability.

Both forecasts mention "thin/illiquid market" (26 contracts/day) as a reason to distrust the 13% anchor, but neither considers that thin markets can also be systematically mispriced toward the *low* side if long-tail YES buyers are scarce/absent, meaning the 13% could actually be an overestimate for unrelated liquidity reasons rather than an underestimate needing upward-adjusted YES weight.

Neither forecast addresses sub-question 6 (missing 435/440/445 rungs) which could have offered a sanity-check on the market's implied ppm-growth curve—this omission means both forecasts rely solely on the Monte Carlo model's internal consistency rather than cross-validating against the market's own broader pricing structure.

6. Aggregator Fable 5.1 · final calibrated forecast

5% (73% confidence)

Yes: 5% No: 95%

The 2025 seasonal peak was ~430.5 ppm and the Met Office projects ~432.2 ppm for May 2026; reaching a 450 ppm monthly mean by the May 2029 peak requires ~4.9 ppm/yr sustained, well above the all-time record of ~3.5-3.75 ppm/yr, and the Monte Carlo puts the 2029 peak near 442.5 ppm with <0.1% chance of ≥450. The only meaningful YES path is resolution ambiguity that would count transient daily/hourly spikes, which is unconfirmed and still requires a multi-sigma excursion on top of an already extreme trend; the ~9% daily-spike figure looks generous given even the p99 monthly tail sits below ~447. The critique's structural-acceleration point is fair but would need an immediate near-doubling of the growth rate sustained for four years, which no feedback mechanism plausibly delivers on this timescale. The 13% Kalshi price is a thin, long-dated tail market where YES is typically inflated by capital costs, and its recent decline toward the quantitative estimate supports discounting it; I land at 5% YES to reflect residual methodology and model-risk uncertainty.

Pipeline Timing

Total pipeline time: 276.7s

Per-tool research timings shown in the Research section above.