Over the past few years, we’ve written several stories about solar storms, coronal mass ejections, the 1859 Carrington Event, and how a modern-day repeat of this phenomenon could be nothing short of disastrous for the US and world economies. Now, a new study predicts that a worst-case scenario could cost the US economy over $40 billion dollars per day, and lead to a nearly complete freeze of manufacturing in key areas across the country.

Before we dive into the findings, let’s backtrack a bit. In 1859, the largest geomagnetic storm on record struck Earth. The coronal mass ejection (CME) that kicked off the event was observed on September 1 and struck the planet on September 2, taking roughly 16.7 hours to make the 93 million-mile journey between Earth and the sun. Auroras were visible in the Caribbean, gold miners woke in the Rockies and began preparing breakfast, thinking it was dawn, and in some cases, telegraph operators were able to send and receive messages despite disconnecting from their power supplies.

At the time, the event was recorded as a considerable curiosity. Today, such a solar storm could be unbelievably catastrophic. Nor are the events terribly unusual — a CME of equivalent strength went off in 2012, but Earth was lucky enough to be in a different location in its orbit and wasn’t hit by the geomagnetic storm.

The new report, aptly titled “Space Weather,” seeks to determine the total economic losses to the United States in various scenarios, ranging from an indirect strike to a geomagnetic storm capable of disrupting the power grid across the United States. As we’ve discussed before, the power grid in America is potentially quite vulnerable to this type of disruption, since the grid literally isn’t designed to handle this type of problem and doesn’t contain any safeguards that would protect directly against it. In fact, some of the strategies you use to mitigate against certain terrestrial problems in the power grid are exactly the opposite of what you might want to do if the power grid was hit by a geomagnetic storm.

The US is vulnerable to some of these disruptions because we make heavy use of high-voltage, low-resistance power lines, with transmission voltages in the 200-700 kV range. These types of lines are more vulnerable to geomagnetically induced current, or GIC.

It is difficult to predict exactly how a massive solar storm will impact the planet or United States. But records from the Carrington Event, direct evidence from a weaker but still-substantial 1989 geomagnetic solar storm that collapsed the Hydro-Quebec power grid, and geological studies of how current moves through various rock strata have allowed scientists to predict the impact of various scenarios, ranging from a limited event isolated in the northern and northwestern United States, to a full-on disaster that destroys most of the power and generation infrastructure in the Northeast corridor.

At first glance, it might seem like only New York State is particularly threatened by the above disruptions. But remember, the losses shown are in real terms, not percentages based on the state’s economic productivity. If a state only has $1B in productivity and loses all of it, it would still be colored light green according to the map.

Calculating economic losses

This new paper tackles the damage question by attempting to analyze both the direct and indirect impacts of a severe geomagnetic storm on everyday life. Most economic analysis have confined themselves to measuring the economic output of those areas that would be affected directly by the grid outage. This new paper goes a step further by calculating secondary and indirect damage as well, as summarized in the image below:

In other words: Previous attempts to analyze economic impacts only focused on the center area, inside the large black box. This project attempted to analyze the very real disruption to supply lines and secondary firms that would occur if large chunks of the country were paralyzed by blown transformers. That’s why the numbers are larger. But the expanded analysis makes sense — if you’re a business located in the Midwest that depends on imports from the coasts to build your products, the complete shutdown of major East Coast transport hubs would severely impact your ability to manufacture goods. Ports in California, Florida, and New Orleans might not be impacted, but delays would be massive, since so many major transport and shipping facilities would be offline.

The other problem is replacing blown transformers. Solar flares play merry hell with transformers and often damage them. I’ll let the report speak directly to the problem of replacing these structures:

The long restoration periods for damage to EHV transformers arise from the average lead time for a bespoke domestically manufactured transformer of 5 to 12 months and for internationally manufactured transformers, of around 6 to 16 months… Moreover, there can be a protracted lead time before their manufacture and delays in physically installing them in place due to their size and weight, which require specialist transport and permits to move them along their chosen route. The secondary effect of transformer damage, including delayed failure in the weeks or months following an event… would cause problems in energy-constrained economies, since the transformers most likely to be affected are generator step-up units and the generator capacity will not be available until the transformer is replaced. In addition to having to replace damaged transformers within the region of the extreme GMD, transformers beyond the region might also be damaged. Units in which damage has been initiated will degrade over weeks or months until they fail, well after the GMD event is over. The failure of these transformers in adjacent regions will increase the pressure on manufacturing replacement transformers.

In short, it could take five to 16 months to completely restore electrical service after a major solar flare. The economic consequences of such an event could bring US GDP to a near-standstill. It might be tempting to write off the prospect of another solar flare as just another example of doom-and-gloom projections that aren’t likely to happen, like the idea of a huge meteor striking Earth.

This, I think, would be a mistake. Unlike civilization-destroying meteors, which don’t show up very often, massive solar flares are well represented in the historical record. Granted, ancient people’s lives weren’t particularly disrupted at the time. But the modern power grid is vulnerable to these strikes in a way that ancient civilizations weren’t.