When the boardroom gets hot: why climate-related health risk is a corporate governance issue

As I write this in mid-July 2026, Europe is in the grip of its third major summer heatwave. The Met Office has issued red warnings for extreme heat in England on consecutive days for the first time since the current warning system began, with Wisley, Surrey recording 35.5°C - the UK's eighth day above 34°C this year, a new national record.

France has seen wildfires rip through the South-West, at least 13 people were killed by a wildfire in Spain's Almeria province over the weekend, and the UK is in the grip of a “firewave” with 19 wildfires across Britain several taking place close to urban areas causing hazards to both homes and health. Preliminary estimates put European excess deaths from this summer's heatwaves at between 15,000 and 20,000 people. The World Health Organization has convened emergency talks with 41 member states, warning that Europe must learn to "plan for heat like winter flu."

These are no longer once-in-a-generation events, with researchers now judging heat of this intensity to be tens to hundreds of times more likely than it was back in 2003. For UK boards, the implication is straightforward: extreme heat is now a recurring and foreseeable operational and human risk. It has the potential to affect employees, customers, tenants, supply chains and the buildings a company occupies, builds, insures or lends against - and it raises a question that is squarely one of corporate governance: what are Directors actually required to do about it?

According to the Companies Act 2006, Directors have a fiduciary duty to promote the success of the company for the benefit of its members (s.172), as well as a duty to exercise reasonable care, skill and diligence (s.174) and to oversee the company’s relationship with its workforce and wider stakeholders. As part of this, Directors should be aware of the risks to which their companies are exposed and should ensure that associated risk management processes are sufficiently robust.

Climate-related physical risks - of which extreme heat and building overheating are a leading example – are now widely regarded as a foreseeable, material business risk: they threaten employee health and productivity, expose occupiers of poorly designed buildings to liability, and affect asset valuations. They also intersect with statutory obligations such as the Health and Safety at Work etc. Act 1974, which requires employers to ensure, so far as reasonably practicable, the health, safety and welfare of employees at work.

A board that treats heat risk as a matter for facilities management alone, rather than as part of its strategic risk oversight and s.172 considerations, is arguably not exercising the reasonable care, skill and diligence the law expects.

It is also important to recognise that heat episodes are but one of the many health related threats associated with climate change. Indeed, the 2025 Report of the Lancet Countdown warned that millions of people around the world are dying needlessly each year due to fossil fuel dependence, growing greenhouse gas emissions, and a failure to adequately adapt. Compiled by 128 scientists across more than 50 countries, this annual report maps 20 indicators of the health hazards of climate change – the latest version finding that health risks are worse than ever before across 13 of those 20 indicators. These include direct heat hazards and exposures; extreme weather events such as droughts and flooding; infectious disease transmission; food security and mental wellbeing – to name but a few. Heat also intersects with other key climate risk factors, such as water scarcity and biodiversity loss, which should be on risk registers. Indeed, as confirmed by a Joint Intelligence Committee report due to be published in November 2025, climate change and nature loss represent one of the biggest threats to UK national security – with food security and fresh water availability of particular concern. So, the evidence base for corporates to treat these as governance-level issues is now substantial and should not be ignored.

While the Taskforce on Climate-related Financial Disclosures (TCFD) ensures mandatory disclosures of climate related risks for larger commercial businesses and financial institutions, many smaller companies with effective boards are choosing to voluntarily report against similar disclosure frameworks. These requirements are further strengthened in the ISSB and UK Sustainability Reporting Standards, which include expectations for more detailed information about the steps governance bodies are taking to assess and manage climate and broader sustainability impacts.

It’s likely that extreme heat will now become a common theme in sustainability reports for many businesses as we regularly see summer heatwave temperatures exceed 30C for several consecutive days in a row. Indeed, the Trade Union Congress has long since called for a maximum indoor work temperature of 30C, or 27C for strenuous work, and the Green Party MP Hannah Spencer has recently committed to introducing a ‘maximum workplace temperature’ bill.

While it may be obvious for boards of construction, infrastructure and utilities businesses to ask probing questions of management to understand workplace policies and the tone from the top during periods of extreme heat, such enquiries should also be taking place in the boardrooms of all businesses as mercury rises and citizens struggle with overheating homes, travel disruption, sleep deprivation, and a general lack of wellbeing and productivity.

Effective boards should also be monitoring the rising trend in climate litigation more broadly – with courts increasingly expressing support for the fact that climate change poses material and foreseeable risks to companies, and that Directors' response to those risks form part of their statutory s.172 and s.174 duties.

A good example here is ClientEarth v Shell's Board of Directors (2023): although the High Court found no prima facie case for Client Earth’s allegation that Shell's directors had breached their duties by failing to adopt a climate strategy capable of meeting net-zero targets aligned with the Paris Agreement, Mr Justice Trower did agree that balancing climate risk against a company's many competing considerations is a "classic management decision" for the board. In other words, boards are very much expected by the courts to turn their minds to climate risk, weigh it seriously against competing considerations, and be able to evidence that they have done so — including, increasingly, the physical and health-related dimensions of that risk, not just transition and emissions strategy.

The direction of travel is clear. Investors, regulators and campaigning groups are converging on the view that climate risk — including the acute, human risk of extreme heat in badly designed or poorly managed buildings — sits within, not alongside, directors' existing fiduciary and care duties. Boards that can demonstrate active, evidenced oversight of these risks, from workforce safety to the overheating performance of their property portfolios, are best placed to withstand both the events themselves and any future legal or regulatory scrutiny that follows them.