{
  "format_version": 3,
  "claim_formal": {
    "subject": "Current global warming",
    "sub_claims": [
      {
        "id": "SC1",
        "property": "Whether Earth's climate has changed in the past",
        "operator": ">=",
        "threshold": 2,
        "operator_note": "SC1 is trivially true and universally accepted by climate scientists. It is included because it is part of the original claim, but its truth does not support the conclusion that current warming is not unusual. 2 sources suffice since this is uncontested."
      },
      {
        "id": "SC2",
        "property": "Whether the current rate of warming is unusual compared to paleoclimate record",
        "operator": ">=",
        "threshold": 3,
        "operator_note": "SC2 is the substantive claim. 'Unusual' is interpreted as: the current rate of warming falls OUTSIDE the range of natural variability observed in the paleoclimate record (ice cores, ocean sediments, tree rings). If 3+ authoritative sources confirm the rate IS unprecedented/unusual, SC2 ('not unusual') is DISPROVED. This is a disproof: we collect sources that say the rate IS unusual."
      },
      {
        "id": "SC3",
        "property": "Whether today's warming is not alarming",
        "operator": "N/A",
        "threshold": "N/A",
        "operator_note": "'Alarming' is a normative/subjective judgment that cannot be formally proved or disproved. Whether warming is 'alarming' depends on values, risk tolerance, and policy preferences. This sub-claim is marked UNDETERMINED."
      }
    ],
    "compound_operator": "AND",
    "operator_note": "The original claim implies: because climate has always changed (SC1), today's warming is not unusual (SC2) or alarming (SC3). SC1's truth does not logically entail SC2 or SC3. The rhetorical structure conflates past natural change with current anthropogenic change. Each sub-claim is evaluated independently. The compound verdict reflects that SC1 is true, SC2 is disproved, and SC3 is undetermined \u2014 yielding PARTIALLY VERIFIED overall."
  },
  "claim_natural": "The climate has always changed \u2014 today's warming is not unusual or alarming.",
  "evidence": {
    "B1": {
      "type": "empirical",
      "label": "SC1: NASA \u2014 paleoclimate evidence of past changes",
      "sub_claim": "SC1",
      "source": {
        "name": "NASA Science \u2014 Climate Change Evidence",
        "url": "https://science.nasa.gov/climate-change/evidence/",
        "quote": "Carbon dioxide from human activities is increasing about 250 times faster than it did from natural sources after the last Ice Age."
      },
      "verification": {
        "status": "verified",
        "method": "full_quote",
        "coverage_pct": null,
        "fetch_mode": "live",
        "credibility": {
          "domain": "nasa.gov",
          "source_type": "government",
          "tier": 5,
          "flags": [],
          "note": "Government domain (.gov)"
        }
      },
      "extraction": {
        "value": "verified",
        "value_in_quote": true,
        "quote_snippet": "Carbon dioxide from human activities is increasing about 250 times faster than i"
      }
    },
    "B2": {
      "type": "empirical",
      "label": "SC1: NOAA \u2014 historical temperature record",
      "sub_claim": "SC1",
      "source": {
        "name": "NOAA Climate.gov \u2014 Climate Change: Global Temperature",
        "url": "https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature",
        "quote": "Earth's temperature has risen by an average of 0.11\u00b0 Fahrenheit (0.06\u00b0 Celsius) per decade since 1850, or about 2\u00b0 F in total."
      },
      "verification": {
        "status": "verified",
        "method": "full_quote",
        "coverage_pct": null,
        "fetch_mode": "live",
        "credibility": {
          "domain": "climate.gov",
          "source_type": "government",
          "tier": 5,
          "flags": [],
          "note": "Government domain (.gov)"
        }
      },
      "extraction": {
        "value": "verified",
        "value_in_quote": true,
        "quote_snippet": "Earth's temperature has risen by an average of 0.11\u00b0 Fahrenheit (0.06\u00b0 Celsius) "
      }
    },
    "B3": {
      "type": "empirical",
      "label": "SC2: NASA \u2014 10x faster than ice age recovery",
      "sub_claim": "SC2",
      "source": {
        "name": "NASA Science \u2014 Climate Change Evidence",
        "url": "https://science.nasa.gov/climate-change/evidence/",
        "quote": "Current warming is occurring roughly 10 times faster than the average rate of warming after an ice age."
      },
      "verification": {
        "status": "verified",
        "method": "full_quote",
        "coverage_pct": null,
        "fetch_mode": "live",
        "credibility": {
          "domain": "nasa.gov",
          "source_type": "government",
          "tier": 5,
          "flags": [],
          "note": "Government domain (.gov)"
        }
      },
      "extraction": {
        "value": "verified",
        "value_in_quote": true,
        "quote_snippet": "Current warming is occurring roughly 10 times faster than the average rate of wa"
      }
    },
    "B4": {
      "type": "empirical",
      "label": "SC2: IPCC AR6 \u2014 unprecedented in 2000 years",
      "sub_claim": "SC2",
      "source": {
        "name": "IPCC AR6 via Carbon Brief",
        "url": "https://www.carbonbrief.org/in-depth-qa-the-ipccs-sixth-assessment-report-on-climate-science/",
        "quote": "key indicators of the climate system are increasingly at levels unseen in centuries to millennia, and are changing at rates unprecedented in at least the last 2,000 years"
      },
      "verification": {
        "status": "verified",
        "method": "full_quote",
        "coverage_pct": null,
        "fetch_mode": "live",
        "credibility": {
          "domain": "carbonbrief.org",
          "source_type": "unknown",
          "tier": 2,
          "flags": [],
          "note": "Unclassified domain \u2014 verify source authority manually"
        }
      },
      "extraction": {
        "value": "verified",
        "value_in_quote": true,
        "quote_snippet": "key indicators of the climate system are increasingly at levels unseen in centur"
      }
    },
    "B5": {
      "type": "empirical",
      "label": "SC2: NOAA \u2014 0.20\u00b0C/decade since 1975",
      "sub_claim": "SC2",
      "source": {
        "name": "NOAA Climate.gov \u2014 Climate Change: Global Temperature",
        "url": "https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature",
        "quote": "the combined land and ocean temperature has warmed at an average rate of 0.11 degrees Fahrenheit (0.06 degrees Celsius) per decade since 1850 and more than three times that rate (0.36 degrees Fahrenheit, or 0.20 degrees Celsius) per decade since 1975."
      },
      "verification": {
        "status": "not_found",
        "method": null,
        "coverage_pct": null,
        "fetch_mode": "live",
        "credibility": {
          "domain": "climate.gov",
          "source_type": "government",
          "tier": 5,
          "flags": [],
          "note": "Government domain (.gov)"
        }
      },
      "extraction": {
        "value": "not_found",
        "value_in_quote": false,
        "quote_snippet": "the combined land and ocean temperature has warmed at an average rate of 0.11 de"
      }
    },
    "B6": {
      "type": "empirical",
      "label": "SC2: U of Arizona \u2014 unprecedented in 24,000 years",
      "sub_claim": "SC2",
      "source": {
        "name": "University of Arizona News \u2014 Kaufman et al. study",
        "url": "https://news.arizona.edu/news/global-temperatures-over-last-24000-years-show-todays-warming-unprecedented",
        "quote": "the speed of human-caused global warming is faster than anything we've seen in that same time"
      },
      "verification": {
        "status": "verified",
        "method": "full_quote",
        "coverage_pct": null,
        "fetch_mode": "live",
        "credibility": {
          "domain": "arizona.edu",
          "source_type": "academic",
          "tier": 4,
          "flags": [],
          "note": "Academic domain (.edu)"
        }
      },
      "extraction": {
        "value": "verified",
        "value_in_quote": true,
        "quote_snippet": "the speed of human-caused global warming is faster than anything we've seen in t"
      }
    },
    "A1": {
      "type": "computed",
      "label": "SC1 verified source count",
      "sub_claim": "SC1",
      "method": "count(verified citations for SC1) = 2",
      "result": "2",
      "depends_on": []
    },
    "A2": {
      "type": "computed",
      "label": "SC2 verified source count (disproof)",
      "sub_claim": "SC2",
      "method": "count(verified citations for SC2 disproof) = 3",
      "result": "3",
      "depends_on": []
    }
  },
  "cross_checks": [
    {
      "description": "SC1: Multiple independent sources confirm past climate changes",
      "n_sources_consulted": 2,
      "n_sources_verified": 2,
      "sources": {
        "sc1_nasa": "verified",
        "sc1_noaa": "verified"
      },
      "independence_note": "NASA and NOAA are independent U.S. federal agencies",
      "fact_ids": []
    },
    {
      "description": "SC2: Multiple independent sources confirm current rate is unprecedented",
      "n_sources_consulted": 4,
      "n_sources_verified": 3,
      "sources": {
        "sc2_nasa_rate": "verified",
        "sc2_ipcc_ar6": "verified",
        "sc2_noaa_rate": "not_found",
        "sc2_arizona": "verified"
      },
      "independence_note": "Sources span NASA, IPCC (international body), NOAA, and University of Arizona (peer-reviewed paleoclimate reconstruction). These are independent organizations using different datasets and methodologies.",
      "fact_ids": []
    }
  ],
  "adversarial_checks": [
    {
      "question": "Are there peer-reviewed studies showing current warming rates are within natural variability?",
      "verification_performed": "Searched for: 'current warming natural variability not unusual peer reviewed', 'climate always changed not unusual scientific evidence'. Found no peer-reviewed studies in reputable journals concluding that the current rate of warming is within natural variability. Climate contrarian arguments exist but are not published in mainstream peer-reviewed climate journals.",
      "finding": "No peer-reviewed literature found supporting the claim that the current rate of warming (~0.2\u00b0C/decade) is within the range of natural paleoclimate variability. The scientific consensus across NASA, NOAA, IPCC, and peer-reviewed paleoclimate reconstructions is that the current rate is unprecedented in at least 2,000-24,000 years.",
      "breaks_proof": false
    },
    {
      "question": "Could the 'Medieval Warm Period' or 'Holocene Thermal Maximum' make current warming seem less unusual?",
      "verification_performed": "Searched for: 'Medieval Warm Period warmer than today', 'Holocene Thermal Maximum vs current warming rate'. The Medieval Warm Period (c. 900-1300 CE) was regional, not global, and its maximum warming was smaller than current global temperatures. The Holocene Thermal Maximum (~6500 years ago) was ~0.7\u00b0C warmer than the 19th century but occurred over thousands of years, not decades.",
      "finding": "Neither the Medieval Warm Period nor the Holocene Thermal Maximum approached the RATE of current warming. The HCM took thousands of years to reach 0.7\u00b0C above baseline; current warming has exceeded 1.3\u00b0C in ~150 years. The rate comparison is the key metric, and it strongly supports the disproof.",
      "breaks_proof": false
    },
    {
      "question": "Is there a methodological dispute about how paleoclimate warming rates are measured?",
      "verification_performed": "Searched for: 'paleoclimate warming rate measurement limitations smoothing bias'. Some researchers note that paleoclimate records have lower temporal resolution and may smooth out short-term spikes. However, even accounting for this, the IPCC AR6 concluded with 'high confidence' that the rate is unprecedented in 2000 years.",
      "finding": "The smoothing limitation is acknowledged in the literature but does not undermine the disproof. Even if past short-term spikes existed, the sustained multi-decadal rate of current warming (0.2\u00b0C/decade for 50+ years) exceeds anything in the record. The IPCC assessment accounts for this uncertainty.",
      "breaks_proof": false
    }
  ],
  "verdict": {
    "value": "PARTIALLY VERIFIED",
    "qualified": false,
    "qualifier": null,
    "reason": null
  },
  "key_results": {
    "sc1_confirmed": 2,
    "sc1_threshold": 2,
    "sc2_confirmed": 3,
    "sc2_threshold": 3,
    "sc1_holds": true,
    "sc2_holds": true
  },
  "generator": {
    "name": "proof-engine",
    "version": "1.2.0",
    "repo": "https://github.com/yaniv-golan/proof-engine",
    "generated_at": "2026-03-29"
  },
  "proof_py_url": "/proofs/the-climate-has-always-changed-today-s-warming-is/proof.py",
  "citation": {
    "doi": null,
    "concept_doi": null,
    "url": "https://proofengine.info/proofs/the-climate-has-always-changed-today-s-warming-is/",
    "author": "Proof Engine",
    "cite_bib_url": "/proofs/the-climate-has-always-changed-today-s-warming-is/cite.bib",
    "cite_ris_url": "/proofs/the-climate-has-always-changed-today-s-warming-is/cite.ris"
  },
  "depends_on": []
}