A real temperature record and a chemical ratio answer different questions — Physics & Environmental Science

The local NASA reading graph retains all 55 annual global land–ocean temperature anomalies from 1970 through 2024 in a dated GISTEMP v4 selection. An anomaly subtracts the 1951–1980 reference mean; it is not the absolute temperature of every place. Changing the baseline by a constant shifts all anomalies equally without changing differences between years. Complete intervals are more informative than selectively chosen endpoints.

A historical warming record is one evidence line. Attribution additionally compares mechanisms, forcings, alternative drivers and expected patterns. Future projections need explicit scenarios and uncertainty. An illustrative curve used to teach a concept must not be relabeled as observations, while a source record should retain coverage, method and baseline metadata.

Ocean acidification uses a different measurement account. Lower pH means greater hydrogen-ion activity even when water remains alkaline. A 0.1-unit fall gives an approximate 1.26-fold hydrogen-ion increase; it does not by itself give the same carbonate decrease. Carbonate equilibria, alkalinity, temperature and salinity help constrain chemistry, and biological effects need measured exposures and appropriate replicated comparisons.