{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2012:BKYCK6GMWX2XXQHTMZ7EKMDKF5","short_pith_number":"pith:BKYCK6GM","canonical_record":{"source":{"id":"1204.5445","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.geo-ph","submitted_at":"2012-04-24T17:39:01Z","cross_cats_sorted":["math.DS","physics.ao-ph"],"title_canon_sha256":"c33147d593db846ba80b64d149315b333fa4b9532d65263ef997df272e8aabb0","abstract_canon_sha256":"ad6741468c8c92dd0a3386e4c4e42aca16e89358b9139a77155d39b7b771ba50"},"schema_version":"1.0"},"canonical_sha256":"0ab02578ccb5f57bc0f3667e45306a2f4f2909d3ba3f6a4ef67faac17940e984","source":{"kind":"arxiv","id":"1204.5445","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1204.5445","created_at":"2026-05-18T03:35:54Z"},{"alias_kind":"arxiv_version","alias_value":"1204.5445v2","created_at":"2026-05-18T03:35:54Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1204.5445","created_at":"2026-05-18T03:35:54Z"},{"alias_kind":"pith_short_12","alias_value":"BKYCK6GMWX2X","created_at":"2026-05-18T12:27:01Z"},{"alias_kind":"pith_short_16","alias_value":"BKYCK6GMWX2XXQHT","created_at":"2026-05-18T12:27:01Z"},{"alias_kind":"pith_short_8","alias_value":"BKYCK6GM","created_at":"2026-05-18T12:27:01Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2012:BKYCK6GMWX2XXQHTMZ7EKMDKF5","target":"record","payload":{"canonical_record":{"source":{"id":"1204.5445","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.geo-ph","submitted_at":"2012-04-24T17:39:01Z","cross_cats_sorted":["math.DS","physics.ao-ph"],"title_canon_sha256":"c33147d593db846ba80b64d149315b333fa4b9532d65263ef997df272e8aabb0","abstract_canon_sha256":"ad6741468c8c92dd0a3386e4c4e42aca16e89358b9139a77155d39b7b771ba50"},"schema_version":"1.0"},"canonical_sha256":"0ab02578ccb5f57bc0f3667e45306a2f4f2909d3ba3f6a4ef67faac17940e984","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T03:35:54.112218Z","signature_b64":"jwbF/HOQcPaN6EYDNx2OKuE9qRBq903TNiBCxUarBqiwOPnfOE8d653C2RluCPx1IbuTwb4ImRGXbQSyAEmKBA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"0ab02578ccb5f57bc0f3667e45306a2f4f2909d3ba3f6a4ef67faac17940e984","last_reissued_at":"2026-05-18T03:35:54.111539Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T03:35:54.111539Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1204.5445","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T03:35:54Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"bKwezX3n3g13PZKS1DtBEFtJPyEa3jgEOoyO7qQIj9dRn2y5prhZ2nWx+jwVoyc1eJAzJyrJpnYIjtt6515fCw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-05T03:13:58.141633Z"},"content_sha256":"f127632fef3d7d9e5702fc1fd9cde7e6341bb9d1a201bc4918c5f26750a1dfab","schema_version":"1.0","event_id":"sha256:f127632fef3d7d9e5702fc1fd9cde7e6341bb9d1a201bc4918c5f26750a1dfab"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2012:BKYCK6GMWX2XXQHTMZ7EKMDKF5","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A recent tipping point in the Arctic sea-ice cover: abrupt and persistent increase in the seasonal cycle since 2007","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["math.DS","physics.ao-ph"],"primary_cat":"physics.geo-ph","authors_text":"Timothy M. Lenton, Valerie N. Livina","submitted_at":"2012-04-24T17:39:01Z","abstract_excerpt":"There is ongoing debate over whether Arctic sea-ice has already passed a `tipping point', or whether it will do so in the future. Several recent studies argue that the loss of summer sea ice does not involve an irreversible bifurcation, because it is highly reversible in models. However, a broader definition of a `tipping point' also includes other abrupt, non-linear changes that are neither bifurcations nor necessarily irreversible. Examination of satellite data for Arctic sea-ice area reveals an abrupt increase in the amplitude of seasonal variability in 2007 that has persisted since then. W"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1204.5445","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T03:35:54Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"p9bj5lpzOj6wIVEvkCix3FWXcdcPGtlNIQN1lBBcJ/TXoXFOMD3nJkk/4so7OH0eQzRVnN4kjHiNAfaH+OOnDg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-05T03:13:58.142207Z"},"content_sha256":"7b85b326f12bc5426677f598af57d40f222b7de569e7c630a96ed72de6f3990d","schema_version":"1.0","event_id":"sha256:7b85b326f12bc5426677f598af57d40f222b7de569e7c630a96ed72de6f3990d"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/BKYCK6GMWX2XXQHTMZ7EKMDKF5/bundle.json","state_url":"https://pith.science/pith/BKYCK6GMWX2XXQHTMZ7EKMDKF5/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/BKYCK6GMWX2XXQHTMZ7EKMDKF5/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-06-05T03:13:58Z","links":{"resolver":"https://pith.science/pith/BKYCK6GMWX2XXQHTMZ7EKMDKF5","bundle":"https://pith.science/pith/BKYCK6GMWX2XXQHTMZ7EKMDKF5/bundle.json","state":"https://pith.science/pith/BKYCK6GMWX2XXQHTMZ7EKMDKF5/state.json","well_known_bundle":"https://pith.science/.well-known/pith/BKYCK6GMWX2XXQHTMZ7EKMDKF5/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2012:BKYCK6GMWX2XXQHTMZ7EKMDKF5","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"ad6741468c8c92dd0a3386e4c4e42aca16e89358b9139a77155d39b7b771ba50","cross_cats_sorted":["math.DS","physics.ao-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.geo-ph","submitted_at":"2012-04-24T17:39:01Z","title_canon_sha256":"c33147d593db846ba80b64d149315b333fa4b9532d65263ef997df272e8aabb0"},"schema_version":"1.0","source":{"id":"1204.5445","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1204.5445","created_at":"2026-05-18T03:35:54Z"},{"alias_kind":"arxiv_version","alias_value":"1204.5445v2","created_at":"2026-05-18T03:35:54Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1204.5445","created_at":"2026-05-18T03:35:54Z"},{"alias_kind":"pith_short_12","alias_value":"BKYCK6GMWX2X","created_at":"2026-05-18T12:27:01Z"},{"alias_kind":"pith_short_16","alias_value":"BKYCK6GMWX2XXQHT","created_at":"2026-05-18T12:27:01Z"},{"alias_kind":"pith_short_8","alias_value":"BKYCK6GM","created_at":"2026-05-18T12:27:01Z"}],"graph_snapshots":[{"event_id":"sha256:7b85b326f12bc5426677f598af57d40f222b7de569e7c630a96ed72de6f3990d","target":"graph","created_at":"2026-05-18T03:35:54Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"There is ongoing debate over whether Arctic sea-ice has already passed a `tipping point', or whether it will do so in the future. Several recent studies argue that the loss of summer sea ice does not involve an irreversible bifurcation, because it is highly reversible in models. However, a broader definition of a `tipping point' also includes other abrupt, non-linear changes that are neither bifurcations nor necessarily irreversible. Examination of satellite data for Arctic sea-ice area reveals an abrupt increase in the amplitude of seasonal variability in 2007 that has persisted since then. W","authors_text":"Timothy M. Lenton, Valerie N. Livina","cross_cats":["math.DS","physics.ao-ph"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.geo-ph","submitted_at":"2012-04-24T17:39:01Z","title":"A recent tipping point in the Arctic sea-ice cover: abrupt and persistent increase in the seasonal cycle since 2007"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1204.5445","kind":"arxiv","version":2},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:f127632fef3d7d9e5702fc1fd9cde7e6341bb9d1a201bc4918c5f26750a1dfab","target":"record","created_at":"2026-05-18T03:35:54Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"ad6741468c8c92dd0a3386e4c4e42aca16e89358b9139a77155d39b7b771ba50","cross_cats_sorted":["math.DS","physics.ao-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.geo-ph","submitted_at":"2012-04-24T17:39:01Z","title_canon_sha256":"c33147d593db846ba80b64d149315b333fa4b9532d65263ef997df272e8aabb0"},"schema_version":"1.0","source":{"id":"1204.5445","kind":"arxiv","version":2}},"canonical_sha256":"0ab02578ccb5f57bc0f3667e45306a2f4f2909d3ba3f6a4ef67faac17940e984","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"0ab02578ccb5f57bc0f3667e45306a2f4f2909d3ba3f6a4ef67faac17940e984","first_computed_at":"2026-05-18T03:35:54.111539Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T03:35:54.111539Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"jwbF/HOQcPaN6EYDNx2OKuE9qRBq903TNiBCxUarBqiwOPnfOE8d653C2RluCPx1IbuTwb4ImRGXbQSyAEmKBA==","signature_status":"signed_v1","signed_at":"2026-05-18T03:35:54.112218Z","signed_message":"canonical_sha256_bytes"},"source_id":"1204.5445","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:f127632fef3d7d9e5702fc1fd9cde7e6341bb9d1a201bc4918c5f26750a1dfab","sha256:7b85b326f12bc5426677f598af57d40f222b7de569e7c630a96ed72de6f3990d"],"state_sha256":"2072a832e227069c761d61e068dae36b50bbea1a277a4bff2eda7cca24ec8f27"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"u0htQUgLMhZIRiWhXwiu4Ib9bYYvrrTYQRgA43UcAHdiRepiMFq50YM5UWZ/GqiyT1/ZzK0kLCgS8+IphJ8eDA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-05T03:13:58.145281Z","bundle_sha256":"313f6bb729b097cd9681af10e1ec898720a534d5a2365027bf7cdd852a84dad4"}}