An unprecedented intentional blackout is affecting hundreds of thousands of people across central and northern California for a second straight day Thursday, with more outages possible in Southern California as desiccating offshore Santa Ana winds ramp up, along with an extreme wildfire risk.

The latest forecasts from the National Weather Service show red-flag warnings continuing in most areas, from the San Francisco Bay region down to San Diego through at least Friday as the weather pattern favors powerful, dry winds blowing offshore. If any fires were to ignite in such conditions, they would be likely to exhibit extreme fire behavior, spread quickly and be difficult to impossible to quickly contain.

The decision by the bankrupt utility giant Pacific Gas and Electric (PG&E) to shut down power ahead of the worst winds is aimed at preventing some of the massive and fast-moving blazes from the past few years, many of which were sparked by downed, active electrical lines operated by PG&E.

These fires include the Camp Fire, which was the state’s deadliest and most destructive blaze on record, which killed 88 and wiped out most of the community of Paradise in just a few hours.

Sparks from downed electrical lines, which gave way during periods of high winds, also triggered many of the wine country blazes in 2017, which destroyed large parts of Santa Rosa.

The utility had attempted more targeted blackouts in the past to shield it from fire liability while protecting communities, but such attempts failed to prove effective.

So, in a bid to limit its own liability in the face of a new high wind event, PG&E has hit the kill switch for a massive swath of infrastructure.

Blackouts are an unusual and unsustainable climate adaptation move

The PG&E blackouts can be viewed as an extreme example of a climate change adaptation measure and one that will have large costs and unintended consequences.

One of the most robust conclusions of climate change research is that wildfires are becoming increasingly frequent and severe in large parts of the American West as the climate warms, particularly in California. This is occurring as summers become hotter and drier and precipitation becomes more variable in the winter, with lurches from drought to flood and back again becoming the norm.

For example, the National Climate Assessment, an authoritative report published by the Trump administration in 2017, cited evidence showing that the cumulative forest area burned by wildfires in the Southwest between 1984 to 2015 doubled because of climate-change-related factors.

In an indication that an uptick in large wildfires is already occurring in California, 15 of the top 20 largest wildfires in state history have all occurred since the year 2000.

Computer model projections show huge increases in wildfire frequency and size in California as well as other parts of the Southwest if greenhouse gas emissions continue largely unabated. In addition to climate change, population growth and the increase in homes and businesses located near lands that typically burn, known as the wildland-urban interface, are also playing a part in escalating the risk of and damage from wildfires in the Golden State.

The state has established the most ambitious climate policy targets in the country, but the consequences of global warming are already here, and increasingly obvious. Since 2010, for example, California residents have dealt with the most severe drought in at least 1,200 years, followed by record wet conditions and back-to-back devastating and deadly wildfire seasons in 2017 and 2018.

Fire experts have warned conditions are conducive to major wildfires given an unusually wet winter that provided a boost to vegetation growth, followed by an unusually hot dry season that dried vegetation out.

The question facing California lawmakers, power company officials and ordinary residents is what to do now that wildfire risks are escalating and vulnerable infrastructure has proved to be a cause of massive, deadly blazes? The answer this time is to impose power cuts that in many areas are going to last several days, but this is not likely to be practical in the long run, given that parts of California see several such strong wind events each fall.

“My personal view is that this is basically a trial-and-error situation,” said Steve Bowen, a meteorologist at Aon, the reinsurance giant.

“The last two years have really changed how we view wildfire risk. There is a lot of brainstorming among many sectors right now to determine how to best mitigate the societal risks since we know wildfire seasons and resultant impacts have grown over time due to climate change influence[s] and human migration patterns,” Bowen said. He pointed out that shutting down power lines only eliminates one ignition source, with lightning and human activity remaining as major threats.

“The temporary suspension of power is just one potential solution to many threats that exist,” he said.

While it is unclear what the losses will be and who will be responsible for paying them, it is possible the costs of the blackouts alone — even if not a single major blaze results from the ongoing high-wind event — will still come close to and may even exceed $1 billion, according to news reports.