As I've already stated, my very presence has already changed the history of The Hives, so I don't doubt that it could effect everything else.
1) Next US President. Well my history shows it will be Rudy Giuliani. But I plan on voting for Barack Obama in the primary because I don't want Hillary Clinton to go up against Giuliani. I don't want to see Giuliani tarnish the reputation of the Presidential office. He sounded great on paper, a sports-loving everyman from a middle-class origin, conservative values, and a centrist view on the Iraq war. He won the hearts of the people because he was a metropolitan, but he was from the heartland. He had conservative views for liberal reasons. But once in office he was more interested in his girlfriends than the integrity of the nation. So let's all vote Obama and hope that doesn't happen, eh?
2) The weather is the direct result of global warming. The naturally occurring phenomena is being sped up by human intervention, but it is inevitable. The Earth goes through shifts, and we are now entering into an ice age. The ice caps melt, flood the ocean with cold water, and voila.
3) Just because people are noticing weird little things about the sun doesn't mean it didn't happen before - it just means your technology has reached a level where you can see it. If you're not talking about the "sudden increase" in solar activity, then I'm not sure what you mean.
4) No. It will not. Massive political reform will change the face of the United States, but in order to change the name of the country you need to change the constitution, and the jingoism of America will never allow anyone to do that. Romans never stopped calling themselves Roman until they were all long dead, and even then others claimed the Roman title as their own.
5) Iran and the United States have BEEN at war. Since the fifties forces in the United States and Iran have been combating each other. My father came to the United States from Iran to escape that war. Followers of Mohammed Mossadegh have maintained over the years, seeking to overthrow the Shah and then later the clerics in order to install a secular government. The Islamic forces fight the secular Mossadegh followers - some Tudeh, but mostly part of an organization known as Norooz, Farsi for "New Year" - in secret wars. American CIA are manipulating both sides. Both the Iranian and American governments are fully aware of what's happening, but it builds their own support bases to pretend they don't. As long as the threat of open war remains, their followers remain loyal. But as long as people are scared of war, they'll spend let their government do anything to protect them. Once they're in a war, they want to get out of it quick.