Global Warming NOT Man-Made?

I am still not sure I even believe the Global Warming is more than a cyclical event in the Earth's history, but I was surprised to hear there is a major new paper out from Russia stating that any recent rise in temperatures MAY NOT be due to fossil fuels but instead something called the Tunguska Event in Sibera in 1908. The key to the theory appears to be new data that shows "global warming" did not begin in any significant way until the early 20th century (and not prior, as theorized by human-centric theories). The Kungstuka Event was a massive strike by a meteor or small comet which may have flung much dust, ice, and water into the atmosphere, changing the whole system of temperature regulation.