SINGAPORE - Climate change and urbanisation are nudging up temperatures in Singapore - and increasing the need for cooling here.
However, a new report has found that the growing use of refrigeration and air-conditioning equipment here has contributed to more emissions of hydrofluorocarbons (HFCs).
Commonly used as refrigerants, HFCs are also greenhouse gases that trap more heat than carbon dioxide.
HFC emissions went up from 4.24 million tonnes of carbon dioxide equivalents in 2014 to 6.26 million tonnes in 2016.
A carbon dioxide equivalent is used as a measure to compare the emissions from various greenhouse gases based on their global warming potential - or the potency of a greenhouse gas in absorbing and trapping heat.
The 2016 figures were highlighted in a December 2020 report that Singapore submitted to the United Nations Framework Convention on Climate Change on its emissions. The 2014 figures were from the report sent in 2018.
The National Environment Agency (NEA), which tracks HFC emissions, said, in response to a query by The Straits Times about the increase, that both figures are not directly comparable as different methodologies were used to calculate them.
The latest report used an updated global warming potential range for HFCs, considering them to be 116 to 12,400 times more efficient than carbon dioxide at trapping heat. The previous report used a range of 140 to 11,700.
By applying the latest calculation to the 2018 report, the updated figure for HFC emissions from the refrigeration and air-conditioning sector in 2014 would be 4.78 million tonnes of carbon dioxide equivalents, said NEA.
"So instead of the 50 per cent increase in HFC emissions... the increase is around 30 per cent," said the agency's spokesman.
This corresponds to a gradual compounded annual growth rate of around 15 per cent from 2014 to 2016, and was due to higher consumer and industrial demand for refrigeration and air-conditioning equipment and servicing, said NEA.
The agency announced in March last year a package of HFC mitigation measures.
They include mandating the recovery, reclamation and destruction of spent refrigerants for chillers and household air-conditioners from July this year, as well as progressively phasing out equipment that uses HFCs with high global warming potential.
"We will continue to monitor emissions from HFCs, with a view to considering further regulatory changes when necessary," said the NEA spokesman, who added that the Government is also exploring ways to reduce the heat in urban areas and reduce reliance on air-conditioning.
This includes studying the effectiveness of "cool paint" to reduce ambient temperature, encouraging passive cooling through urban design, and increasing greenery along the streetscapes and through vertical and rooftop greenery.
The National University of Singapore's Energy Studies Institute research fellow Melissa Low said that while HFC emissions account for around only 1 per cent of global emissions, they are growing at a rate faster than all other greenhouse gases.
Studies have estimated that uncontrolled growth of HFCs could nearly cancel the entire benefit obtained from controlling carbon dioxide emissions, she added.
Ms Low noted that controlling HFC emissions could be hindered by the lack of safe alternatives, as most HFCs are non-toxic and non-flammable. Proposed replacements, such as hydrofluoroolefins and natural substances like ammonia and propane - have either flammability or toxicity issues.
She said Singapore's measures were important to address the issue of the existing stock of equipment using refrigerants with high global warming potential.
Once these emissions are measured and controlled, focus may be shifted towards enabling the adoption of HFC alternatives with lower global warming potential.
"But safety standards related to the use of HFC alternatives in refrigeration and air conditioning equipment have to be carefully considered," she said.