At the 30th UN Climate Change Conference (COP30) in Belém, Brazil, SINTEF Chief Scientist Petter Nekså participated in several events discussing the barriers that must be overcome to achieve energy-efficient, climate-friendly cooling solutions.
This article is based on a series of LinkedIn posts published by Petter Nekså from COP30.
Active vs. passive cooling
On the first day of COP30, several countries declared new Nationally Determined Contributions (NDCs). If fulfilled, these pledges will reduce global CO2-equivalent emissions by 12% by 2035. While the atmosphere among COP participants was positive, much deeper emission reductions are needed to reach net zero by 2050.
With global temperatures climbing, the need for cooling is rapidly increasing, particularly for air conditioning. In high-income countries, the financial costs associated with increased power production for this purpose are manageable – although there are also environmental costs due to increased emissions until power production is fully decarbonised.
“When temperatures increase to new levels, often not experienced in certain areas before, active cooling will be needed, if it can be afforded. Performing this in a sustainable and energy-efficient manner is paramount,” said Petter Nekså.
However, in low- and middle-income countries, a different approach to combat the heat will be required. One possibility presented at the COP high-level session “Beat the Heat” was the use of low-tech passive cooling measures, such as re-introducing trees and green spaces to urban areas.
At Building and Cooling Pavilion, a researcher from Australia demonstrated that the temperature in areas with few trees and vegetation was 5-8°C higher than in greener spaces. While these measures will cost less, their success depends on urban planning practices and commitment from policymakers.
At the “2025 Ministerial Roundtable: Delivery of the Global Cooling Pledge at COP30”, there was a clear increase in countries adopting the pledge as well as EPIC- the Pledge’s implementation mechanism.
Natural refrigerants are needed
Another challenge to address is reducing emissions from refrigerants themselves. Currently, many cooling systems use hydrofluorocarbons (HFCs), which are powerful greenhouse gases. Replacing them with natural refrigerants, such as CO2, ammonia, hydrocarbons, air and water provides a climate-friendly and health-safe solution.
One area where this has been significant has been in cold chains for the food industry. The use of R-717 (ammonia) and R-744 (CO2) for chilling and freezing food is well established. In European supermarkets R-744 is also well established, and the installation of these systems are now expanding to other countries world-wide, including the United States.
However, adoption in refrigerated transport remains limited. Petter spoke about this issue as part of an event on “Advancing Sustainable Cold Chains with Natural Refrigerants”, where he represented the International Institute of Refrigeration (IIR):
“For reefer containers and trucks, R-744 and R-290 are in the market, but numbers are limited. Efforts on research and development should be made to get these applications also over on a sustainable track.”
