Radiative forcing from anthropogenic land cover change since A.D. 800
Article first published online: 30 JAN 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 2, January 2009
How to Cite
2009), Radiative forcing from anthropogenic land cover change since A.D. 800, Geophys. Res. Lett., 36, L02709, doi:10.1029/2008GL036394., , , , and (
- Issue published online: 30 JAN 2009
- Article first published online: 30 JAN 2009
- Manuscript Accepted: 16 DEC 2008
- Manuscript Revised: 9 DEC 2008
- Manuscript Received: 22 OCT 2008
- anthropogenic land cover change;
- radiative forcing;
- last millennium
 We calculate the radiative forcing (RF) from surface albedo changes over the last millennium applying a recently published, population-based reconstruction of anthropogenic land cover change (ALCC). This study thus allows for the first time to assess anthropogenic effects on climate during the pre-industrial era at high spatial and temporal detail. We find that the RF is small throughout the pre-industrial period on the global scale (negative with a magnitude less than 0.05 W/m2) and not strong enough to explain the cooling reconstructed from climate proxies between A.D. 1000 and 1900. For the regional scale, however, our results suggest an early anthropogenic impact on climate: Already in A.D. 800, the surface energy balance was altered by ALCC at a strength comparable to present-day greenhouse gas forcing, e.g., −2.0 W/m2 are derived for parts of India for that time. Several other regions exhibit a distinct variability of RF as a result of major epidemics and warfare, with RF changes in the order of 0.1 W/m2 within just one century.