PCMDI leads research into the detection of significant changes in Earth’s climate, and into the attribution of variability and change to specific causes. We are best known for pattern-based “fingerprint” studies, which have contributed to findings of a natural and anthropogenic forced influence on global climate. This work has considered a wide-range of changes to the Earth system and included analyses of atmospheric temperature, precipitable water, ocean heat content, and key aspects of the hydroclimate.