This is nothing less than pestulent anti-science! Next they'll say second hand smoke isn't dangerous!!
A compiled list of all the sources can be seen here. The total amount of cooling ranges from 0.65C up to 0.75C -- a value large enough to wipe out nearly all the warming recorded over the past 100 years. All in one year's time. For all four sources, it's the single fastest temperature change ever recorded, either up or down.
Scientists quoted in a past DailyTech article link the cooling to reduced solar activity which they claim is a much larger driver of climate change than man-made greenhouse gases. The dramatic cooling seen in just 12 months time seems to bear that out. While the data doesn't itself disprove that carbon dioxide is acting to warm the planet, it does demonstrate clearly that more powerful factors are now cooling it.