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There is no question that the drought and heat across the western US is bad right now. Unseasonably high temperatures have baked Washington and Oregon, with new highs of 41.7掳C in Seattle on Monday and 44.4掳C in Portland on Sunday. Canada, better equipped for blizzards, has also suffered in a deadly, record-breaking heatwave.

A dry winter means exceptional and severe drought now blankets large swathes of the western US states, with hot summer months still to come 鈥� leading to worries of another potentially disastrous wildfire season. The drought is intense even for a region that played host to a historic six-year drought from 2011. 鈥淚t鈥檚 extraordinarily bad already,鈥� says Peter Gleick at the Pacific Institute in Oakland, California.

These spectacularly dry conditions don鈥檛 guarantee a wildfire season worse than last year鈥檚 devastating blazes, says at the University of California, Los Angeles. But they do set the stage for one, by creating an abundance of tinder dry fuel. Compared with last year, California has seen a 56 per cent increase in the area burned up to 10 June.

These extremes are playing out in a world that has warmed around 1.1掳C since pre-industrial times. So what does the US west coast face if the world warms by the 2.9掳C that governments鈥� current policies have us on track for?

鈥淭he short answer is the future holds more of this and worse. By this, I mean more severe droughts and more severe wildfire seasons,鈥� says Swain.

鈥淲hat we can say for the climate for the region is it鈥檚 not going to get better, especially California,鈥� says at the University of Oxford. 鈥淚t鈥檚 one of the regions that, already at low [global] warming levels, sees an increase in hot and dry [conditions]. We see an increase in hot extremes basically everywhere in the world, but dry only in specific regions 鈥� and this is one of them.鈥�

Climate change is expected to mean less snowfall and more rain in the western US, reducing the winter snowpack that provides a crucial supply of water. Mount Rainier in Washington state, a key source of snowpack, has seen melting at triple the normal rate for this time of year.

Modelling by Swain and his colleagues suggests future rain and snow in the region will also be much more volatile, with dramatic year-to-year swings, counterintuitively raising the risk of both flooding and drought. A major US climate report found the south-western US .

at the Nature Conservancy, a US non-profit organisation, says these changes will exacerbate demand for water. Future soil moisture is expected to be lower in winter and spring, a key time for farmers. 鈥淚f it鈥檚 dry as a bone when it鈥檚 prepared for crops, you鈥檙e going to need a lot more water from underground aquifers, so you鈥檙e going to run through it faster,鈥� she says.

None of these climate impacts will be welcome in the western US, especially not another so-called 鈥渉eat dome鈥� like the one that brought the recent intense heat (see 鈥�What is a heat dome?鈥�, below). But, says Hayhoe, 鈥淔uture change is not set in stone.鈥�

Experts agree that the long-term solution to avoiding the worst impact is the rapid and deep cut in global greenhouse gas emissions demanded by the 2015 Paris Agreement. The world is failing on that score, a shortcoming this November鈥檚 COP26 climate summit is meant to address.

In the meantime, there remains the big question of how western North America can best adapt to drought, fire and heat, now and in the future. Short-term responses to fires include fireproofing of buildings against embers, clearing grass around homes and not stacking fire wood under eaves. 鈥淏ut those are not large-scale, hugely helpful solutions to any of the broader problems and don鈥檛 address any of the underlying issues,鈥� says Swain. Medium-term responses give him the most cause for optimism. 鈥淲hat can we do by September? Not a hell of a lot. What can we do in five to 15 years? Probably quite a lot.鈥�

Fight fire with fire

Two key options are thinning vegetation to reduce the fuel available, and intentionally starting controlled burns, also known as prescribed fire. at Arizona State University says thinning, which is already under way in California, can play a big role but is hamstrung by time and cost. The cost is not just financial but social and political, he says. Consultations with local people can take years. 鈥淭hings are moving so fast, we don鈥檛 have time to spend a decade talking,鈥� he says.

Controlled burns already take place across the western US and Canada. But they aren鈥檛 without risk 鈥� some have escaped control in the past 鈥� and can be unpopular with local people who are understandably afraid of fire and the health impacts of smoke. 鈥淭here needs to be [prescribed] fire on the ground in large quantities but there are practical and political impediments,鈥� says Swain. 鈥淭he first step is probably a public education campaign to show not all fires are created equal. Some produce more benefits than harms. And people need to understand the choice is not between smoke and no smoke.鈥�

Partly because of such barriers, Pyne says the firefighters he speaks to in the west鈥檚 rural areas are increasingly trying to transform wildfires into what are effectively controlled burns. Critical infrastructure is still protected, but some firefighters are backing off from putting out fires on a ridge or two to an easily defensible position and then systematically allowing them to burn out. 鈥淭hat is a hybrid model. It鈥檚 not that you鈥檙e equally suppressing the fire at all points, you鈥檙e adjusting it,鈥� says Pyne.

Stopping fires igniting in the first place will be vital. Upgrading and maintaining energy networks should be 鈥渉igh priority鈥� and can be done quickly, says Swain. Fires started by power lines often occur in the most dangerous conditions, with strong winds that turbocharge blazes. A notable example is the 2018 Camp Fire in California, which caused 84 deaths and was found to be due to power lines run by the Pacific Gas and Electric Company. The company filed for bankruptcy after to manslaughter.

With 85 per cent of US fires started by people, greater public awareness and penalties may seem like a solution, too. But despite media reports focusing on fires started by gender-reveal parties and children with matches, arson is rare and isn鈥檛 often linked to large fires. 鈥淭he real issue in a landscape that is intrinsically this flammable is there鈥檚 only so much you can do to reduce accidental human ignitions,鈥� says Swain.

The western US also desperately needs to accelerate its adaptation to the drought that sets the stage for such fires. Some of that is obvious, says Hayhoe, such as reducing demand for water through more efficient toilets, showerheads and other appliances. Some farmers are switching from pivot irrigation 鈥� mounted sprinklers where much of the water is lost 鈥� to drip irrigation. 鈥淭here鈥檚 a lot of low hanging fruit when it comes to efficiency,鈥� says Hayhoe.

Tackling demand is also crucial, says Gleick, because traditional measures to increase water supply in the region, such as reservoirs, aqueducts and pipes, are no longer enough. 鈥淲e are now at what I call peak water. We can鈥檛 have any more water from the Colorado river,鈥� he says. The Colorado river provides water for some 40 million people in the US, and one of its key reservoirs hit a historic low this year.

Alongside tougher water standards for products, Gleick wants to see more of the behaviour changes that authorities call for in emergencies to become the norm, such as short showers, letting lawns brown or removing lawns entirely, and washing cars less. In the long run, coastal cities could resort to building desalination plants to make more use of seawater, but Gleick says alternatives such as water reuse plants remain a better and cheaper option for now.

In the short term, reducing agriculture鈥檚 water demand offers the biggest absolute savings. Gleick says farmers are working hard on water efficiency, but California, a major food producer, may have to reluctantly accept growing less. He thinks the state鈥檚 farmland will need to reduce by around 10 per cent. 鈥淚 would argue in California some land is going to have to come out of production. We鈥檝e brought more land into production than we have water for,鈥� he says.

Ultimately, the climate-change-fuelled extremes facing the western US will hinge on how ambitiously the world tackles the emissions driving those impacts. But in parallel, it is clear there are ways to adapt to them, and they are becoming increasingly urgent. 鈥淚 think we can adapt, yes. But the question is will we?鈥� says Gleick.

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