As temperatures continue to rise, driven by the climate crisis, tourism spots may face more overcrowding at certain times of the year and temporary closures due to heat, flooding and storms, the charity has warned.
The changing conditions may mean tourists will have to adapt the way they spend their vacations, such as avoiding going out during the hotter parts of the day like in southern Europe.
The National Trust analysed data from more than 85 million pre-pandemic visits to 170 of its coastal and countryside sites, castles, stately homes, gardens and historic buildings across England, Wales and Northern Ireland.
Comparing the visitor data with weather conditions, the trust found that a quintessential “National Trust” day across all its locations would be one with temperatures of 21C, moderate winds and little rain.
It also found people preferred visits to indoor properties at 20C, with the numbers of people choosing to go to stately homes and other historic buildings declining if the temperature rises above that.
The optimum temperature for people to go to outdoor locations, particularly beaches and coasts, is 24C, but numbers decline dramatically once temperatures reach 28C.
Climate change could mean more visits to sites at current “off peak” times as spring and autumn become warmer and summer becomes too hot. The research suggests that this could shift tourism high season from its current peak of July and August to autumn.
But with hot days expected to become more frequent due to global warming, the National Trust has warned that the £127bn UK-based tourism industry may not be ready for the extreme weather that rising temperatures are set to bring.
If no action is taken to reduce greenhouse gas emissions dramatically, an increasing number of stately homes and other indoor venues may have to temporarily close more often due to excessive heat or storms brought on by climate change.
Caretakers of such venues may have to take on work to cater for a possible increase in visitors to the coasts in spring and early summer, and invest in making indoor venues more resilient to high temperatures, rain and humidity.
The National Trust called on the government to take action and bring world leaders together at the COP26 climate talks in Glasgow in November to limit global temperature rises.
It also urged the government to produce a strategy to cut the UK’s emissions to net zero. It comes after the organisation produces a “hazard map” which plots potential climate change threats to its sites across the country.
Lizzy Carlyle, head of climate and environment at the National Trust, said: “What this data shows us is that we have a lot to do to prepare the UK tourist industry for the effects of climate change.
“Much of the debate around tourism and climate change to date has rightly focussed on international travel and the impact flights and foreign holidays is having.
“But what hasn’t been fully addressed is what the domestic tourism industry could be facing unless we take drastic action to reduce emissions.”
She added: “What we can do, however, is start to adapt sites to cater for local pressures, for example more capacity for outdoor shaded seating, the ability to deal with surges of visitors at off peak times of year as the weather changes and how to protect staff and volunteers from things like extreme heat.
“In time, there could also be a need for a slight cultural shift in our approach as tourists, like avoiding hotter parts of the day like those currently experienced in southern European countries,” she added.
“The National Trust is already taking action across the places we care for to ensure sites are ready for these changes, but there is much to be done across the industry to collectively prepare us for more frequent days above 30C, higher winds and increased flooding.”
Additional reporting by PA