A lot of people have been trying to answer this exact question. Part of the problem is that we didn't have all the observations that we have today (of the Sun and around the Earth) back then, so we don't know exactly what the conditions were.

But the best guess is that it would be pretty bad. It would probably knock out most instruments on satellites, including communication satellites, which means most digital communication would be lost or at least affected. This includes electronic banking, smart phones, internet, etc. as well as GPS. It would change the upper atmosphere of the Earth, causing problems with radio waves making communication very difficult. It could cause significant pulses of current in power lines which could melt the transformers they are connected to, which would result in wide spread electricity blackouts.

Fixing all the damage is estimated to take months to years and cost in the billions to trillions of dollars worldwide.

However, with enough warning, some of these effects could be minimized. This is why so many people are working to create and improve our ability to predict space weather. It is a tough problem but we're making steady progress!

We do know how this looks on a smaller scale, because there was a power outage in Quebec in 1989 that was caused by a solar storm. But as the previous poster said, we don't quite know the magnitude of what would happen if a very big event, like the Carrington event, happened today. And the technology upon which we rely today is very different than in 1989!

Hi Peter!

One of the things that is difficult to predict about the potential effects of a huge geomagnetic storm like the Carrington Event is how widespread electrical power blackouts would be. Some regions of the US and other countries would be a lot more strongly affected than others. It depends on a lot of different factors, including the age of the equipment running the power grid, how interconnected the power supply to different areas is, and the geology of the local regions affected. It turns out that some places are more susceptible to the types of geomagnetically induced currents (or GIC) that caused the power outages in Quebec and parts of the US during the 1989 storm. This is a very important issue that scientists and engineers are working to understand better.