Sustainable cooling could save thousands of lives

A collaborative study by the International Energy Agency (IEA) and Yale University has found that it is possible to provide affordable cooling to an ever-growing population and also avoid increasing greenhouse gas (GHG) emissions.  

Keeping people cool can save tens of thousands of lives each year, the report says. Those without access to indoor cooling are at high risk of heat stress, as excess heat adversely affects thermal comfort, labour productivity, and human health.

According to the IEA/Yale University study, during 2019–2021 an estimated 190,000 lives were saved per year by increased use of air conditioning. However, AC that is not efficient, affordable and resilient can create a cycle of further harm to the climate and health.

Currently, increasing demands on AC globally is putting stress on the power grid, exacerbating the adverse impact of space (indoor) cooling on GHG emissions, local air pollution and power outages; and creating urban heat island effects, energy poverty, and physiological acclimatisation, the IEA/Yale University report says. Higher temperatures caused by climate change, coupled with increasing incomes and growing populations, are driving rapid growth in residential AC ownership.

Alternatively, passive cooling methods such as shading (e.g., verandas), cross-ventilation (e.g., windows or other openings on opposite walls), and light-coloured building materials that reflect the rays of the sun, protect the climate by conserving energy and keeping energy costs low.

But in many parts of the world, active solutions such as fans (low energy), and AC (higher energy), are the primary approaches to indoor cooling. According to the IEA/Yale University report, about 1.5 billion units were installed worldwide by the end of 2021.

And global household AC ownership is expected to reach 45 per cent by 2030 – up from 35 per cent in 2021. This is good news for protecting against heat-related illness and mortality, but uncontrolled growth and use of AC could exacerbate related health and climate harm.

According to the report, however, access to effective cooling does not need to come at the cost of the environment.

It points to a suite of technical and policy solutions that can deliver efficient, climate friendly, and health promoting cooling. The IEA’s Net Zero Emissions by 2050 Scenario lays out a pathway towards net zero CO₂ emissions at the global level by 2050 while still providing universal energy access and ensuring affordable energy supply.

The scenario sets three space cooling-related goals for 2030. First, 20 per cent of total existing building floor area globally and all new building construction is made zero-carbon-ready by 2030. Second, AC temperatures are set at 24–25°C. Third, the average efficiency rating of new AC equipment is increased by at least 50 per cent in all markets by 2030.

This target is achievable through enforced minimum energy performance standards (MEPS) and building energy codes, and through greater international collaboration, says the report. Implementing these measures would limit to 10 per cent the growth of global electricity demand for space cooling in the period 2021–2030, compared to 40 per cent growth without these measures, it says.

Additional high-priority measures to reduce AC energy demand include more passive solutions such as green and blue spaces; high-albedo (i.e., high ability to reflect the sun’s rays) streets and sidewalks; and advanced building design.

AC sustainability can also be improved through proper installation, maintenance, and end-of-life material management, particularly for GHG refrigerants, the report says.

The document discusses the sustainability challenges associated with AC and the promise of alternative cooling solutions that, if adopted widely, can provide effective cooling while substantially reducing energy demand for AC.

The full IEA/ Yale University analysis can be found here.