LA Times claims that models show that "...non-greenhouse gas factors could have accounted for only about 1% of the warming experienced since 1950"

Climate-change denial getting harder to defend - latimes.com

Similarly, Markus Huber and Reto Knutti of the Institute for Atmospheric and Climate Science in Zurich found by using simulation models that non-greenhouse gas factors could have accounted for only about 1% of the warming experienced since 1950.
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Glen M. MacDonald chairs UCLA's Institute of the Environment and Sustainability and is a professor of geography and of ecology and evolutionary biology.