The Carbon Dioxide Information Analysis Center (CDIAC), located at the U.S. Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL), is the primary climate change data and information analysis center for DOE. CDIAC is supported by DOE's Climate and Environmental Sciences Division within the Office of Biological and Environmental Research (BER). CDIAC's data holdings include estimates of carbon dioxide emissions from fossil-fuel consumption and land-use changes; records of atmospheric concentrations of carbon dioxide and other radiatively active trace gases; carbon cycle and terrestrial carbon management datasets and analyses; and global/regional climate data and time series. CDIAC provides scientific and data management support for numerous projects including large-scale DOE ecosystem experiments like the Next-Generation Ecosystem Experiments; the AmeriFlux Network, continuous observations of ecosystem level exchanges of CO2, water, energy and momentum at different time scales for sites in the Americas; the Ocean CO2 Data Program of CO2 measurements taken aboard ocean research vessels; and the HIPPO project, which measured and is analyzing the atmospheric carbon cycle and greenhouse gas concentrations from pole to pole over the Pacific Ocean. Datasets cover: (1) Stable Isotopic Composition of Atmospheric Carbon Dioxide (13C and 18O) from the NOAA ESRL Carbon Cycle Cooperative Global Air Sampling Network, 1990-2014; (2) Atmospheric Hydrogen Mixing Ratios from the NOAA GMD Carbon Cycle Cooperative Global Air Sampling Network, 1988-2005.