The UK is one of the countries that will have to adapt the most radically to cool down buildings as climate change drives up the global average temperature, according to a new study.

Like other countries in Northern Europe, such as Ireland, Switzerland and those in Scandinavia, homes were built to retain heat during cold winters.

But rising temperatures because of climate change means more unwanted heat during the summer, which can be fatal for older and more vulnerable people.

A new study, published in Nature Sustainability, has measured the increase in the number of “cooling degree days” (CDDs) for countries around the world if and when the Earth’s average temperature increases from 1.5C to 2C above pre-industrial levels.

CDDs refer to how frequently and how far above a baseline of 18C (averaged over day and night) the temperature rises in a particular area, though this does not account for heatwaves or the effect of urban heat islands, where cities are hotter than their surroundings.

These increases in relative change are going to mean that we need deployment of cooling adaptation measures at a fast speed and at a large scale

They are essentially a measure of how many times a country will need to implement cooling measures – in whatever form that takes – in order to return the indoor environment to a comfortable level.

In the UK, the current mean average of CDDs is 36 and this is expected to rise to 69 if the global average temperature reaches 1.5C.

If the global temperature rises still further to 2C, the number of average CDDs will be 89 – a rise of just under 30% from 1.5C, the study found.

Only Ireland and Switzerland showed a higher relative increase.

The researchers, from the University of Oxford, found that countries bordering the southern limit of the Sahara desert would see the greatest absolute number of CDDs, with the Central African Republic seeing an increase of more than 266 between a 1.5C and 2C global temperature rise.

These countries will be more exposed to heat than any other which could stunt their socioeconomic growth, placing an unfair burden on people living there because they have contributed the least to global warming via greenhouse gas emissions, Dr Radhika Khosla said.

She also said that “no country is shielded from these impacts” and that northern countries will also have to radically adapt.

Dr Nicole Miranda, lead author of the study, said: “In the northern hemisphere in Europe, the buildings are made to keep heat in.

“And so we are at risk in the summertime, when heatwaves come or when higher temperatures in general come that we overheat our buildings.

“Even a small increase in the temperatures are actually showing a high relative change which can be very impactful and make these countries more vulnerable to needing more cooling.

“And of course, these increases in relative change are going to mean that we need deployment of cooling adaptation measures at a fast speed and at a large scale.”

The scientists warned of a “vicious cycle” developing whereby people burn more fossil fuels to provide energy for cooling which then heats the climate still further, requiring more energy.

It is predicted that the amount of energy needed just for cooling by 2050 will be equivalent to the combined 2016 electricity use of Japan, the United States and the European Union.

Dr Miranda warned against not preparing for the rising heat and then later taking the easier option of installing air conditioning, which would be inefficient and only exacerbate the problem.

Some of the solutions proposed for retrofitting buildings were to introduce ventilation measures that could also be closed off to keep in heat during winter and extendable shading covers such as awnings or more trees next to buildings to reflect the suns rays.

The researchers also suggested having personal fans that cool only the space occupied by people and not entire rooms that are empty, or for buildings where air condition is necessary, installing a heat pump that can cool in summer and warm in winter.

Philip Dunne MP, chair of the Environmental Audit Committee, said: “The alarming findings of this important research from the University of Oxford should give us all pause for thought.

“It is deeply concerning that the UK is among the three countries that will see the largest increase in temperature, particularly as we know that the UK is not yet adequately prepared for the consequences.

“Hotter summers are our new normal: we must learn to adapt to them and to mitigate the harms that extreme hot weather will bring.”