Slashing non-carbon dioxide (CO2) pollutants, particularly short-lived climate pollutants, such as methane, could put the emergency brake on rising temperatures, avoiding between 0.4 degrees Celsius and 0.6 degrees Celsius of warming by 2050, said Dr Durwood Zaelke, co-founder of the Washington-based Institute for Governance and Sustainable Development.
For comparison, if the world successfully decarbonises by just targeting CO2 emissions by 2050, only 0.1 degrees Celsius of warming could be avoided.
“This is because when you shut down fossil-fuel facilities, you unmask existing warming, as short-lived sulphates, which cool the planet, fall out in a matter of days,” said Zealke, who is also a professor and author.
He was one of the key speakers at last week’s World Sustainable Development Summit (WSDS) organised by The Energy and Resources Institute (TERI).
In an interview with PTI, Zealke said for example, the International Maritime Organisation introduced strict limits on the sulphur content of marine fuels in 2020.
While this reduced sulphur dioxide (SO2) emissions, the move has warmed the planet by an estimated 0.04 degrees Celsius.
The world is rapidly approaching a sustained breach of the 1.5-degree Celsius threshold set by the 2015 Paris Agreement.
The last three years have been the warmest on record, with the average temperature rise being 1.51 degrees Celsius.
“That is why cutting non-CO2 pollutants is crucial. For example, methane is the biggest and fastest way to cool the planet, capable of avoiding 0.29 degrees Celsius of warming by the 2040s,” said Zaelke, whose organisation aims to build resilience by accelerating fast climate-mitigation actions to slow near-term warming.
Apart from methane, other key non-CO2 pollutants are hydrofluorocarbons (HFCs), chlorofluorocarbons (CFCs), tropospheric ozone and black carbon soot.
However, coming up with a collective action to slash these pollutants would be a challenge for the world, as global efforts to tackle the climate crisis have been undermined in recent months.
In January, the United States withdrew from 66 international organisations and conventions- the most significant being its exit from the United Nations Framework Convention on Climate Change (UNFCCC).
According to Zaelke, the world needs to take inspiration from the 1989 Montreal Protocol, which helped recover the ozone layer by phasing out the production and use of ozone-depleting substances.
“The Montreal Protocol has shown that we can start small- with citizen boycotts of CFCs in hairspray- and grow into a treaty with universal membership that has avoided nearly 100 per cent of damaging chemicals.
It has kept us from going over the cliff of disaster,” Zaelke said. (PTI)
