This visualization displays a global drought atlas dating back to 1400, created using data from tree rings. The data is displayed on a flat rectangular map projection with a simple overlay depicting the differences in tree ring sizes for dry and wet years. In the second half of the visualization, a ‘fingerprint’ thumbnail is introduced, which is an indicator for human influences on climate change. A signal-to-noise ratio graph is depicted comparing the fingerprint to both tree ring drought atlas data and observational meteorological data (CRU and Dai)
Human-generated greenhouse gases and atmospheric particles were affecting global drought risk as far back as the early 20th century, according to a study from NASA’s Goddard Institute for Space Studies (GISS) in New York City.
The study compared real-world data with climate models, which predicted that human influences could be seen early in the 1900’s and would increase. To the researchers’ surprise, clear evidence of a human “fingerprint” — a global drought pattern more likely to occur if greenhouse gases are affecting the climate — emerged within the first half of the last century. While the study included various human and natural influences, the only one that consistently increased across the century and the globe was greenhouse gases, suggesting they drove the fingerprint.
The study is the first to provide historical evidence connecting human-generated emissions and drought, suggesting that forward-looking climate models are accurately predicting future drought conditions and that humans play a key role in their location and severity, the team said.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 126.96.36.199.0