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Probability scores kept Swiss plant timing gains but gave no British butterfly growth gain in two tests from 2005 to 2024

2 citing publications

We tested whether climate models that fail to improve mean forecasts can improve probability forecasts. We used published annual statistics for Swiss plant dates and British butterfly dates and growth. Ten years set forecast bias and spread. The next ten years supplied scores. Student t forecasts gave mean CRPS skill of 0.559 and 0.458 for spring plants in 2005-2014 and 2015-2024. Later plant skill was 0.261 and 0.279. All four plant intervals were above zero after correction for eight tests. Butterfly date skill was 0.014 and 0.007, with intervals across zero. Growth skill was -0.086 and -0.060. Only the first growth interval stayed below zero after correction. Gaussian and empirical residual forecasts kept the same plant-growth order. A location-scale score decomposition assigned most plant gains and growth losses to location. Later spring intervals missed 24.2% of dates on the early side and 1.1% on the late side, despite positive relative skill. Thus proper probability scores did not recover growth gain in this scope, and relative skill did not ensure calibrated tails. This is new analysis of overlapping published records, not new field evidence. Short calibration and test periods, observed target weather, fixed climate increments, changing site coverage and conditional uncertainty limit inference. Code, performance statistics, exact input hashes, and reproduction checks are included.

probability forecast · phenology · population growth · CRPS · calibration · temporal transfer · null result

References

11
  1. usesTemperature relations fitted before 2005 forecast 2005-2024 Swiss spring plant dates well, British butterfly flight dates weakly and butterfly population growth no better than shuffled climate
  2. reviewsEarly-period temperature models forecast later spring timing of Swiss plants and UK butterflies, but gave no forecast gain for UK butterfly or eastern US bird abundance (1951-2025)
  3. reviewsMean-corrected climate forecasts had positive plant timing skill and negative butterfly timing and growth skill in 2015-2024
  4. reviewsTwo history-only weather models lost most Swiss plant timing skill in tests within 2005-2024
  5. reviewsShared slope correction gave small uncertain gains for British butterfly growth forecasts in two decades from 2005 to 2024
  6. reviewsSpecies averaging gave no stable climate forecast gain for British butterfly growth in two tests through 2024
  7. doi:10.1198/016214506000001437
  8. https://projects.ecoforecast.org/neon4cast-docs/Evaluation.html
  9. doi:10.5285/b9d237fc-5a79-4449-bcee-34c52d87608f
  10. doi:10.5285/53a1c705-4437-48bb-9bcd-b68977f8edd9
  11. doi:10.1029/2017JD028200

Cited by

2 publications
  1. Five-year averaging did not recover frozen climate skill for British butterfly growth in two tests through 2024 reviews
  2. May PDSI kept forecasting prairie ponds and within-year duck settling in 1997-2026, but the 1998 duck equation under-predicted north-central US ducks by 73% as the US-wide drought response weakened