Some 135 wildfires burned out of control during the first six months of last year, which with a spate of similar incidents in 2018 caused more damage than in the whole of the previous decade, according to data analysed by the Moorland Association.
Smoke from fires in the Pennines exposed around 5m people to levels of pollution exceeding the recommended limits laid down by the World Health Organization, the figures show.
The economic fallout from the blazes on Saddleworth Moor and Winter Hull is estimated at £21.1m, while further fires at Marsden, near Huddersfield, and on Ilkley Moor cost more than £500,000 to put out.
The careless use of portable barbecues by day trippers has been blamed by fire authorities for most of the incidents.
Experts say the current dry spell has made the moors a tinderbox once again, and have repeatedly urged visitors to stay away.
The Moorland Association’s director, Amanda Anderson, said the dry weather had “significantly raised the risk” of wildfires on the moors.
“The greatest danger is the environmental devastation, and I do mean devastation,” she told The Yorkshire Post.
“The vegetation at this time of year harbours ground nesting birds and anything there, from curlews to lapwings, are destroyed. There is no grazing for hill sheep and nothing for red grouse to eat, if they survive.”
The peat soil on the moors is also a natural carbon storage facility which, if released, would be the equivalent of five years of England’s regular CO2 emissions, the Association says.
“The peatlands lock away pollution from the industrial era, and setting fire to it releases particles that will be breathed in by people further down the valley,” Ms Anderson said.
There has already been a significant fire this year on Meltham Moor, near Huddersfield, which saw firefighters tackling a “mile-long fire-front” at Deer Hill reservoir, at the end of last month.
The outbreak saw two water companies, who together own more than 30 moors in Yorkshire, Lancashire and Derbyshire, instruct tenants to abandon their annual programme of controlled heather burning – a practice which reduces older growth without affecting the underlying peat. The official burning season ended this week.