Health Effects of Climate Change (HECC) report: cold
Source: gov.uk (2025-09-24)

The 2023 Health Effects of Climate Change (HECC) report provides an analysis of how climate change makes extreme weather events such as cold, more intense and variable.

CCHS navigation menu: CCHS homepage (https://www.gov.uk/government/organisations/the-centre-for-climate-health-security)Topic: weather-related hazards (https://www.gov.uk/government/collections/climate-related-hazards) Hazard: cold (https://www.gov.uk/government/collections/cold-weather)

Key chapters on cold from the HECC report:
- Health Effects of Climate Change report: cold
- HECC report (https://www.gov.uk/government/publications/climate-change-health-effects-in-the-uk#:~:text=Chapter%201%3A%20State%20of%20the%20UK%20past%20and%20future%20climate)
State of the UK past and future climate (chapter 1)

Even though the changing climate and rising temperatures will mean that the UK is likely to experience warmer and wetter winters, cold weather and colder winters are predicted to continue, with weather patterns and temperatures varying across the UK and over time. While warmer winters will reduce the health risks from extreme cold the risks from moderate cold are likely to remain.

Both heat and cold-related deaths are predicted to increase, with cold continuing to have a significant impact due to an aging population. Cold weather will remain a considerable risk to health until the middle of the century but as climate change progresses it will become less frequent.

Temperature and mortality (chapter 2)

Because of the UKs ageing population, cold-related deaths are projected to increase before beginning to decline from the middle of the century onwards as temperatures increase further.

The health impacts of cold are not felt equally among the population and there are certain groups who are at increased risk from cold.

Population groups most at risk from cold weather include:
- people over the age of 65, including those who are frail or socially isolated
- young children and babies
- pregnant women
- people with underlying health conditions (particularly cardiovascular or respiratory conditions), including mental health conditions
- people with disabilities, learning difficulties or cognitive impairment
- people experiencing homelessness or who are rough sleeping
- people who are housebound or otherwise have low mobility
- people in a lower income households
- people living in poor quality housing
- people living in households experiencing fuel poverty
The health risks of cold include:
- increased risk of heart attacks and strokes
- increased risk of chest infections and influenza
- increased risk of falls
Cold weather is linked to impacts on mental health such as anxiety and depression and is associated with excess deaths in the UK. Many deaths and cold related illnesses are preventable.

Climate and air pollution (chapter 4)

Weather can affect how much air pollution there is, depending on things like temperature, wind speed, and air pressure. When the air moves very slowly, pollution can build up and cause air pollution episodes, especially during heatwaves in summer or cold weather in winter. The amount of pollution you’re exposed to can also depend on where you live geographically. People living near busy roads are more likely to be affected by higher levels of air pollution.

Breathing in air pollution can affect your health, from the possibility of developing heart and lung problems to shortening your life. There is also some evidence that polluted air may affect cognitive skills and increase dementia risk.

Weather can also affect the quality of the air inside homes and buildings. Using solid fuels like coal and wood for heating is becoming more common in UK homes, despite evidence that doing so can significantly increase the amount of harmful particles in the air - increasing particulate matter concentrations to almost 3 times higher than in homes without wood burning stoves. These indoor sources of pollution can be harmful to health, especially if there isn’t enough fresh air coming in, if the ventilation systems aren’t working well, or if windows are kept closed to stay warm and save on heating costs during cold weather.

Climate change and infectious diseases (chapter 7)

The changing climate will likely influence how many infectious diseases there are and how they spread, by affecting how microorganisms survive and grow in their environments. For example, temperature can change geographically where these diseases are most likely to be found.

When the weather gets colder, more people tend to stay indoors, which can make it easier for illnesses to spread, especially respiratory infections like colds and flu. In England and Wales, norovirus infections increase as temperatures get colder. Similarly, in other countries, the number of cases of rotavirus tend to increase during colder temperatures.

As temperatures in the UK get warmer over time, there may be fewer cases of winter viruses spreading. However, it’s not certain how much the risk will decrease because there are many other factors that can affect how these viruses spread.

Net zero health impacts (chapter 14)

The UK has committed to reaching net zero greenhouse gas emissions by 2050. Some net zero policies may have co-benefits, resulting in health improvements alongside reducing emissions, however careful consideration needs to be given to how net zero policies are implemented to avoid unintended health consequences.

Improvements in building insulation as part of net zero policies can reduce energy consumption and greenhouse gas emissions while improving indoor comfort during the winter and cold weather. This could lead to reductions in cold-related illnesses and deaths, particularly for those living in fuel poor homes or those who are more vulnerable to the health impacts of cold. However, as the UK warms further in the future, these adaptations will need to include adequate ventilation to prevent occupants from overheating during the summer and hotter weather.

Climate change indicators (chapter 15)

Indicators and metrics are important for monitoring progress towards achieving adaptation and mitigation goals, at a local, national, and international scale.

Relevant cold weather indicators include:
- the proportion of housing stock with low indoor temperature
- the number of households in fuel poverty
- annual cold-related mortality and morbidity data
- the proportion of homes with (retrofit) energy efficiency upgrades by type