Eletromagnetic pulses have been a consideration since the 1940s, when the effects were first noted during nuclear testing. The scientists who noticed the phenomenon still had no clear understanding of the significance at that time, although one scientist in 1925 had begun to notice the way atoms worked and put forth the theory of an e-bomb.
EMP Events in History
Carrington Event
In the end of August and beginning of September 1859, there was a geomagnetic solar storm that caused widespread effects, including aurora-type displays and interruption of telegraph systems. Two British astronomers, Richard Hodgson and Richard Carrington, were observing the solar landscape and recorded the “white light flare” that was associated with the phenomenon. The term used when the sun has a major solar flare like this is coronal mass ejection (CME) and these happen fairly regularly; however, they rarely travel directly toward Earth and therefore do not usually have an effect on Earth’s electronics.
Some of the effects observed around the world included electric shocks to telegraph operators, sparks flying from telegraph pylons, and bright auroras that made some people believe it was morning, even though it was not yet. Despite this, some telegraph systems were still working just fine. In fact, some operators found that the aurora contained enough power to run the telegraph machines when they were not plugged in to their batteries, allowing messages to continue to be sent.
Starfish Prime
July 1962 was when the United States conducted this high-altitude nuclear test. This was meant to be a series, together known as Operation Fishbowl, and the specific test was known as Starfish Prime. It was planned to launch one called Bluegill first, but the radar tracker was unable to follow it and that required it to be destroyed before reaching the desired location for detonation.
Starfish Prime was detonated at 250 miles above the middle of the Pacific Ocean and its results were as expected. The EMP result, however, was larger than they had expected, and went beyond the scale of the instruments being used at the time. Some electrical damage occurred in Hawaii, nearly 900 miles away from the launch site, including damage to streetlights and a microwave link belonging to the telephone company and setting off burglar alarms. It also damaged several satellites.
Kazakhstan
Russia also conducted some nuclear EMP tests around the same time. There were seven of them from September 6 through November 1 of 1961-1962. These tests were conducted over top of residential areas, with the intent to determine the extent of the damage to electronics. There was a military base in the test range, where the people who were not involved in the tests and who were not essential military personnel were restricted to quarters for the duration of the testing.
While the Soviets obtained much data and information from these tests, many of their results have not been released for the general public. They did make known what damage was experienced, which included telephone line disconnections, radio satellite damage, power generators broken, transformers burning, long line problems, and more.
1989
A geomagnetic storm took place in March 1989 due to a CME. A variety of solar flares and solar storms had been happening during the time period, but one of them affected the Earth profoundly. Its first effect was the intense auroras that started at the poles but were so huge that the northern one was visible in Florida and Texas.
Further damage included a blackout of communication, including shortwave radio and other radio signals. Some have claimed that nuclear submarines noticed frequency changes and some satellites near the poles were temporarily disabled and communication from others was disrupted. It may also have been the cause of elevated pressure readings on a hydrogen tank on the Space Shuttle Discovery.
Quebec was affected more than most areas, with power grid circuit breakers becoming tripped and power failure for about nine hours.
Possibly ~774AD
Scientists have found potential evidence that a gamma-ray burst may have impacted the earth around 774-775 AD. This is based on the increase of carbon-14 in Japanese trees that would have happened around that time, based on the rings. Similar increases have been noted in trees in America and Europe, as well. To correlate this evidence, there are also increases of the radioactive element beryllium-10 in ice in Antarctica.
Possibly 993
A similar carbon-14 increase in tree rings has been found at the 993 AD rings of some trees, as well as increase in beryllium-10, as in 774. It is thought to have been a solar storm.
Political and Military
Research has been continued to determine the risk of EMP damage from natural or man-made sources. Scientists continue to examine the solar landscape and record changes in hopes of having enough information to predict a potential EMP event before it happens. The military studies the potential of military-grade EMP events in nuclear and non-nuclear situations.
Studies in 2010 and 2011 indicated that the US might not be sufficiently protected in the case of a military EMP attack. The studies considered nuclear high-altitude attacks and how they may affect the country.
Whenever non-USA military groups have nuclear capabilities, the possibility of EMP attacks are raised. In November 2018, the Air Force released a report that examined the potential of an EMP attack from North Korea, Russia, or Iran. The report discussed the potential impact on such things as the military, the population in general, interference with electricity, healthcare, transportation, and the processing of food items. It also considered the impact on things like nuclear reactors, which require electricity for cooling, jets, power, GPS, and more.
In 2019, President Trump considered the potential threat of EMP from Russia, China, North Korea, and Iran and signed an executive order on March 26 entitled “Executive Order on Coordinating National Resilience to Electromagnetic Pulses” to study the risks to the US. This can determine what steps need to be taken to make the US as EMP-resistant as possible.