US Extreme Weather and Climate Change Dashboard

A project by Roger Pielke Jr., author of The Honest Broker

Check out the Global Dashboard
What's New

Methodology

This entire site is possible because of publicly available data, funded by taxpayers and governments around the world. Open science is good science.

↓Methodology & Sources — full PDFData provenance, detection framework, reliable-trend windows, and known limitations for every variable, in one document.

Detection and Attribution

This dashboard focuses only on detection, following the IPCC's framework for detecting a change in climate. The IPCC's definitions are below (Glossary, AR5/AR6/SR15, "Detection and Attribution"), and this site applies them throughout.

Detection and attribution are two distinct steps, and this dashboard performs only the first. Detection asks whether observations have changed in a defined statistical sense, without saying why. Attribution asks why — evaluating the relative contribution of specific causal factors (greenhouse gas forcing, land-use change, natural variability, and so on) typically requires climate model simulations run with and without a given forcing, a substantially larger undertaking, and outside this project's scope. No panel on this site states an attribution finding. A panel marked "Detected Change" says two things about the observed trend: chance internal variability alone would rarely produce it, and it runs large against that variability. It says nothing about a cause, human or otherwise.

Detecting a change is also not the same as spotting a trend in a chart. Any naturally variable quantity drifts up and down over any finite stretch purely from year-to-year (or week-to-week) variability, with no underlying change in the climate at all — a trend line by itself proves nothing. IPCC's detection criterion asks whether that trend is unlikely to have arisen from natural internal variability by chance alone, specifically at the stated example threshold of below 10% (via the nonparametric Mann-Kendall test used throughout this site). This dashboard goes one step beyond IPCC's minimum: because a long, low-noise record can register a statistically real trend even when its actual size is trivial next to the variable's natural variability, a trend earns the detected change label here only if it also clears a second, magnitude-based bar — see the "Magnitude-vs-variability check" definition. A trend can clear IPCC's likelihood criterion and still not count as a detected change on this site for that reason.

Detection and time of emergence

Detection asks whether a change has already appeared in the observational record. Time of emergence asks when a signal rises above the noise around it, and the literature answers that in several different ways: AR6 WG1 Chapter 12 names two definitions in its opening sentence on the subject and adopts a signal-to-noise convention only where a study does not specify otherwise. A third approach asks how many years a record must run before a projected signal could show up at all. TheDetection and Time of Emergence page sets out the three, reproduces AR6's Table 12.12, and runs the third calculation on both TXx series tracked here.

Charts on this site already show a years-to-detection figure (Weatherhead et al. 1998) where a variable renders no detected change, and that figure takes its trend magnitude from the record under test, which makes it post-hoc. Read it as a description of what the record could resolve. The emergence timescale on the page above takes its trend magnitude from AR6 instead, which is what lets it say something the p-value does not.

Sources

Data Sources — Attribution & Licensing

Every dataset behind this site is publicly available, and most are US government works with no copyright restriction (17 U.S.C. §105). A few come from non-US or university-hosted producers with their stated citation or attribution convention — this page quotes those verbatim below rather than paraphrasing them.

Definitions

Known caveats

Full per-variable detail, including validation against known historical events and every documented limitation, is available in the Methodology & Sources PDF.