BER launches Environmental System Science Program. Visit our new website under construction!

U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights

Revisiting 2000 Years of Climate Change
Published: September 22, 2008
Posted: January 27, 2009

Knowledge of climate change over past centuries provides the context of modern climate change; however, the lack of widespread instrumental climate records necessitates the use of proxy data such as tree-rings, corals, ice cores, and historical documentary records. A recent study in the September 8 issue of the Proceedings of National Academy of Sciences USA, co-authored by DOE-sponsored researcher Ray Bradley of the University of Massachusetts Amherst, examines reconstructions of surface temperature at hemispheric and global scale for the past 2000 years, using a greatly expanded set of proxy data. The 1998 ‘hockey stick’ reconstruction of Bradley et al. (referring to the shape of the time versus temperature curve) has been challenged by some in the climate change research community due to uncertainties in tree-ring data that were used. The new study is significant since it demonstrates that Northern Hemisphere surface temperature warming appears anomalous for at least the past 1300 years whether or not tree-ring data are used. The amplitude of warming during the Medieval Warm Period is greater than previously reported, albeit still not reaching recent levels.

Reference: Mann M.E., Z. Zhang, M.K. Hughes, R.S. Bradley, S.K. Miller, S. Rutherford and F. Ni. 2008. "Proxy-based reconstructions of hemispheric and global surface temperature  variations over the past two millennia," Proc. Natl. Acad. Sci. USA 105, 13252.

Contact: Anjuli Bamzai, SC-23.1, (301) 903-0294
Topic Areas:

  • Research Area: Earth and Environmental Systems Modeling

Division: SC-33.1 Earth and Environmental Sciences Division, BER


BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

Mar 23, 2021
Molecular Connections from Plants to Fungi to Ants
Lipids transfer energy and serve as an inter-kingdom communication tool in leaf-cutter ants&rsqu [more...]

Mar 19, 2021
Microbes Use Ancient Metabolism to Cycle Phosphorus
Microbial cycling of phosphorus through reduction-oxidation reactions is older and more widespre [more...]

Feb 22, 2021
Warming Soil Means Stronger Microbe Networks
Soil warming leads to more complex, larger, and more connected networks of microbes in those soi [more...]

Jan 27, 2021
Labeling the Thale Cress Metabolites
New data pipeline identifies metabolites following heavy isotope labeling.

Analysis [more...]

Aug 31, 2020
Novel Bacterial Clade Reveals Origin of Form I Rubisco

  • All plant biomass is sourced from the carbon-fixing enzyme Rub [more...]

List all highlights (possible long download time)