If global blackout happens, that means we're all dead. With all the renewables on this blue ball it's impossiblegor the global outage. Of course electromagnetic storms are real and could definitely happened not just from our sun but other weird space object in the space shooting space beams from hundreds of thousand of light-years away.

Being hit from all sides is unlikely.

But if that happens, we can say goodbye to earths atmosphere and Mars will get new brother.