CPO's Climate Observations and Monitoring (COM) Program and the National Centers for Environmental Information (NCEI) Applied Research Center (ARC) partner to develop authoritative datasets that utilize existing in situ, satellite, and paleoclimate observations for broad community use. The COM-NCEI ARC/Paleo projects, in close coordination with NCEI’s World Data Service for Paleoclimatology, have resulted in a number of high quality datasets over the last 5 years. Significant advancements over the last 5 years in understanding societally-relevant risks such as drought and temperature changes in a long-term context would not have been possible without the development and compilation of these paleo datasets. For example, the COM-ARC/Paleo datasets provided evidence for an early onset of anthropogenic warming, documented that the current spatial pattern of temperature changes is unlike that of the pre-industrial past, and supported an assessment that the 21st century drought in the southwest and Great Plains of North America is likely to be unprecedented in a long-term context. 

ARC partners have also engaged stakeholders to ensure that these datasets are findable and in readily useable formats to increase the use of paleoclimate data for analyses and to test climate model skill (e.g. Paleo-DIVER, Federated Search, Controlled Vocabularies). Datasets generated and compiled by the COM-ARC partnership are foundational to advancing the understanding of climate variability and change and have gone on to undergird the competitive research funded by CPO programs, including cutting-edge research supported by the Climate & Global Change program**.

Below are some examples of high profile-publication outcomes from CPO programs' funded projects that utilized ARC-developed datasets:

•  Zhu, F., J. Emile-Geay, N.P. McKay, G.J. Hakim, D. Khider, T.R. Ault, E.J. Steig, S. Dee, J.W. Kirchner. 2019. Climate models can correctly simulate the continuum of global-average temperature variability. Proceedings of the National Academy of Sciences 116: 8728-8733. doi: 10.1073/pnas.1809959116 [ice cores, lake sediments, marine sediments, tree rings, corals, speleothems, historical documents; 0 CE to present]
• **Steiger, N.J., J.E. Smerdon, B.I. Cook, R. Seager, A. P. Williams, E.R. Cook. 2019. Oceanic and radiative forcing of medieval megadroughts in the American Southwest. Science Advances 5: eaax0087. doi: 10.1126/sciadv.aax0087. [ice cores, lake sediments, tree rings, boreholes, marine sediments, corals, sclerosponges; 0 CE to present]
• **Neukom, R., N. Steiger, J.J. Gomez-Navarro, J. Wang, J.P. Werner. 2019. No evidence for globally coherent warm and cold periods over the preindustrial Common Era. Nature 571: 550- 554. doi: 10.1038/s41586-019-1401-2 [ice cores, lake sediments, tree rings, corals, bivalves; 0 CE to present]
• Emile-Geay, J., K.M. Cobb, M. Carre, P. Braconnot, J. Leloup, Y. Zhou, S.P. Harrison, T. Correge, H.V. McGregor, M. Collins, R. Driscoll, M. Elliot, B. Schneider, A. Tudhope. 2016. Links between tropical Pacific seasonal, interannual and orbital variability during the Holocene. Nature Geoscience 9: 168-173. doi: 10.1038/ngeo2608. [corals; 9,000 years ago to present]
• **Hoffman, J.S., P.U. Clark, A.C. Parnell, F. He. 2017. Regional and global sea-surface temperatures during the last interglaciation. Science 355: 276-279. doi: 10.1126/science.aai8464 [sea surface temperature reconstructions; 129,000 to 116,000 years ago]
• Cook, B.I., T.R. Ault, J.E. Smerdon. 2015. Unprecedented 21st century drought risk in the American Southwest and Central Plains. Science Advances 1: e1400082. doi: 10.1126/sciadv.1400082. [tree rings; 1000 CE to present] https://advances.sciencemag.org/content/1/1/e1400082 
• Cook, E.R. and 56 others. 2015. Old World megadroughts and pluvials during the Common Era. Science Advances 1: e1500561. doi: 10.1126/sciadv.1500561. [tree rings; 0 CE to present] https://advances.sciencemag.org/content/1/10/e1500561