UKHSA's HECC report shows impacts on public health due to warming climate

UKHSA has today published its first HECC report, drawing together the latest evidence on how our changing climate is already impacting on the nation’s health and publishing future projections based on a plausible worst case scenario.

The report contains 15 chapters written and peer-reviewed by a wide range of experts from academia, industry and government, providing detailed analysis on climate change issues that will inform further research, public health practice and policy decisions going forward.

It is the first report of its kind produced since 2012. It demonstrates that the evidence base on the health effects of climate change has grown significantly, with health threats from heat, mosquitos, flooding and food security becoming more significant in the near future.

Both at home and across the world, we are already seeing the health effects of increasingly extreme weather. In the summer of 2022, the UK saw temperatures reach above 40°C for the first time on record, with nearly 3,000 excess deaths recorded across the period, while many other countries have experienced bouts of intense and prolonged heat in recent months.

This report examines the future relationship between temperature and mortality in climate change. Using a high-emissions scenario, UK-heat related deaths are estimated to increase by one and a half times in the 2030s and by 12 times by 2070.

Under the same scenario, cold-related deaths are also projected to increase for a period before declining, with deaths from extreme cold declining by the mid-century, and deaths from moderate cold peaking around the same time and seeing a decline by the 2070s. Deaths due to cold will therefore continue to present a substantial mortality burden.

Public health interventions and wider adaptations can have a major impact in reducing temperature-related risks to health for both heat and cold. Protecting older adults and considering the social determinants of vulnerability is vital to lever for minimising health risks. Evidence of substantial variation in geographic and social vulnerability to heat and cold highlights that there is scope for interventions to be targeted to improve the resilience of places and communities.

Many infectious diseases are highly climate sensitive, and with warmer temperatures it is increasingly likely that we will see the introduction and establishment of a number of invasive mosquito species in the UK, as well as the projected spread of existing species into habitats that were previously inhospitable to them.

Climate modelling under a high emissions scenario suggests that Aedes albopictus – a mosquito species that can transmit dengue fever, chikungunya virus and zika virus – has the potential to become established in most of England by the 2040s and 2050s while most of Wales, Northern Ireland and parts of the Scottish Lowlands could also become suitable habitats later on in the century.

Under this scenario, London could experience endemic dengue transmission by 2060. The risk of establishment of Aedes albopictus in the UK is of great concern for public health.

Dr Lea Berrang Ford, Head of Centre for Climate and Health Security at UKHSA, said:

The evidence is clear – climate change is not solely a future health threat. Health impacts are already being felt domestically and globally, and these risks will accelerate.

Temperatures will likely continue to increase until at least mid-century, irrespective of the amount by which we decarbonise in the decades to come. Many current working-age adults will be over 65 years and potentially highly vulnerable to the health impacts of increased temperatures. A child born today will be in their working-age years when health impacts may peak or accelerate further, depending on how much we decarbonise now.

There are significant opportunities for win-win solutions that can combat climate change and improve health.

The health decisions we make today will determine the severity and extent of climate impacts inherited by today’s youth and their children.

Professor Isabel Oliver, Chief Scientific Officer at UKHSA, said:

This report starkly demonstrates the impact that climate change could have on our society if we do not take decisive action. We can expect major impacts on physical and mental health, while our changing climate will also exacerbate existing health inequalities.

In the UK, many of the anticipated adverse impacts on health are still avoidable through mitigation measures, while others are preventable if the necessary adaptation measures are introduced. Therefore it is critical that the evidence in this report is used to inform policy and action.

The changing climate will be the backdrop upon which our government and health and social care organisations will need to secure the health of individuals and communities in this century, so it is vital that together we focus and accelerate our efforts on these mitigation and adaptation measures.

The United Nations Framework Convention on Climate Change (UNFCCC) established the goal of limiting warming to below 1.5°C (no higher than 2°C), a figure that is widely expected to be exceeded in the next 5 to 10 years. Current global actions and policies to reduce or remove greenhouse gases emitted into the atmosphere put us on a collective trajectory closer to 2°C to 3°C warming, with projections of over 4°C considered a plausible worst-case scenario.

The report sets out that the greatest opportunity for health in the context of climate change comes from the potential to align health goals with the UK’s decarbonisation agenda. If these health goals are embedded in decarbonisation strategies, there is the potential to generate a range of health benefits, particularly through air quality, food, housing and transport.

In January 2023, an independent review was published by the government, with the analysis demonstrating that the decarbonisation pathway outlined in the Net Zero Strategy is still the most beneficial one to follow. The UKHSAHECC report also sets out where the UK currently stands in terms of reaching its targets, and what needs to be considered in the years to come in order to continue on that pathway.