Only by thoroughly examining climate history can we estimate natural contributions and evaluate earth's sensitivity to rising CO2. (landscapesandcycles.net)
Most studies showed that recent natural contributions have been in the cooling direction, thereby masking part of the human contribution and in some cases causing it to exceed 100 % of the total warming. (skepticalscience.com)
This is why the sum of human and natural contributions from Jones et al. 2013 exceeds 100 % in Figure 1 — because the modeled warming slightly exceeds the observed warming. (skepticalscience.com)