Anthropogenic? People keep throwing out terms like "clear" and "settled" and when asked to elaborate give responses like "it's in the science." So what specific conclusion in the science is now beyond questioning? Citation needed.
Have you read or consulted parts of the IPCC report? That links to nearly all relevant science on this topic, and is so well understood by everyone talking about this topic, that when they say "the science" that is at least what they are referring to.
Yes, that event will cause the sun to start burning helium instead, and will swell to a red giant approximately the radius of the orbit of Mars.
In about 4-5 billion years.