SINGAPORE - Carbon dioxide (CO2) levels in the atmosphere hit a new high in May, helping to fuel global warming that is busting temperature records, as well as causing crippling heatwaves and more extreme floods.
The effects of global warming are being felt across the globe, meaning the higher CO2 levels go, the greater the impact on people and communities, especially in the poorest nations because they are less able to adapt to the impacts.
Scientists say the recent heatwave that baked parts of India and Pakistan was made much more likely because of climate change.
CO2 levels are now 50 per cent above the pre-industrial average, before humans began the widespread burning of oil, gas and coal in the late 19th century.
There is more CO2 in the atmosphere now than at any time in at least four million years, US National Oceanic and Atmospheric Administration (Noaa) officials said on Friday (June 3). And once released into the atmosphere, CO2 stays there for decades to centuries.
The concentration of the gas reached nearly 421 parts per million (ppm) in May, the peak for the year. Emissions totalled 36.3 billion tonnes in 2021, the highest level in history, driven by an economic rebound from the pandemic.
Power plants, industry, transport and agriculture are large CO2 sources and nearly every aspect of most people’s lives can lead to the release of more CO2, from switching on the air-conditioner and driving to the office, to taking a plane and buying imported food.
The gas acts like a blanket, trapping heat in the atmosphere. As the amount of CO2 increases, the planet keeps warming, because humanity is adding more than natural processes can absorb. Forests, soil and oceans soak up large amounts of CO2, but humanity is adding more than nature can cope with.
Average global temperatures are now about 1.1 deg C higher than in pre-industrial times. Unless CO2 levels are drastically cut this decade, the world could reach 1.5 deg C within a decade, says the United Nations’ climate panel.
Limiting warming to 1.5 deg C is the threshold beyond that scientists say the likelihood of catastrophic effects of climate change increases significantly.
Rising temperatures, especially heatwaves, are the strongest evidence of climate change, scientists say.
During Singapore’s recent long spell of hot, humid weather, the nation hit the second-highest temperature on record in April, peaking at 36.8 deg C in Admiralty, just 0.2 deg C shy of the all-time high recorded in Tengah on April 17, 1983.
Last month, the mercury hit 36.7 deg C, also in Admiralty, the highest recorded temperature for the month of May.
Weather experts say Singapore is not in the grip of a heatwave, adding that the temperatures are within the norm.
But higher temperatures are expected in future for Singapore and the world with global warming.
A recent study on South Asia’s heatwave during March and April found it was about 30 times more likely due to human-induced climate change. Peak temperatures of more than 45 deg C were recorded in many parts of India in April, which was the third-hottest in 122 years.
On May 14, Jacobabad in Pakistan was one of the hottest cities on earth at 51 deg C.
Before the Industrial Revolution, levels of CO2 held steady at around 280 ppm, a level maintained for approximately 6,000 years of human civilisation, according to Noaa.
The level now is comparable to what it was between 4.1 million and 4.5 million years ago, when CO2 levels were near or above 400 ppm, the agency said in a statement.
At that time, sea levels were between 5m and 25m higher than now, high enough to submerge many of today’s major cities.