She led a 2006 study examining climate sensitivity, then commonly accepted as 1.5–4.5K in response to a doubling of atmospheric CO 2, to review observational studies suggesting that climate sensitivity could be as much as 7.7K or even exceed 9K. By using large-ensemble energy balance modelling to simulate temperature responses to historic changes in the radiative forcing effect of solar changes, volcanic eruptions and greenhouse gases, and comparing this to climate reconstructions, they produced an independent estimate that climate sensitivity was probably within the range of 1.5–6.2K.[1] In an interview with The Washington Times, Hegerl said "Our reconstruction supports a lot of variability in the past".[12]