A Climate Clock for San Jose, CA

Historical Data


Geologic Time Scale — Data from proxy measurements

  • boron isotope ratios
  • carbon isotope ratios
  • stomata counting on leaf fossils

Past 400000 years — Data from Antarctic ice cores

Post-industrial (1850–present) — Data from Antarctic ice cores or, since 1959, directly measured at Mauna Loa



Current data directly measured since 1850; data quality controlled and adjusted, and tabulated by GHCN