CO2 and methane concentrations spiked to record highs again last year

The greenhouse gas carbon dioxide hit a near 65-year high in 2023, according to data released by NOAA on April 5. Scientists are also concerned about the rapid rise in atmospheric concentrations of methane, a shorter-lived but more potent heat-trapping gas. Both have increased by 5.5% over the past decade.

CO2 and methane levels surge above all-time highs in 2015 — Concentrations of heat-trapping gases in the atmosphere reached a historic high in 2023. Photo: AP

Between January and December 2023, atmospheric CO2 concentrations increased by 2.8 parts per million (ppm). While that’s not as high as the spikes in 2014 and 2015, it puts CO2 concentrations higher than any year since 1959. The average CO2 level in 2023 was 419.3 ppm, a 50% increase from pre-industrial levels.

Methane increased by 11.1 parts per billion (ppb) last year. Methane averaged 1,922.6 ppb last year. NOAA atmospheric scientist Xin “Lindsay” Lan, who did the calculations, said methane has increased by 3 percent in just the past five years and is 160 percent above pre-industrial levels, showing a faster rate of increase than CO2.

Methane emissions into the atmosphere come from natural wetlands, agriculture, livestock, landfills and leaks, and the oil and gas industry. According to the International Energy Agency, methane is responsible for about 30% of the current rise in global temperatures.

According to the US Environmental Protection Agency (EPA), methane is about 28 times more effective at trapping heat than CO2, but it stays in the atmosphere for about a decade instead of centuries or thousands of years like CO2.

The third largest human-caused greenhouse gas, N2O, rose 1 ppb last year to a record high. N2O, which can persist in the atmosphere for about a century, comes from agriculture, fuel burning, fertilizers and industrial processes, according to the EPA.

“These numbers show that we must do more to make significant progress in reducing greenhouse gas concentrations in the atmosphere,” said NOAA Global Monitoring Laboratory Director Vanda Grubisic.

Last year, a slew of companies around the world pledged to almost completely cut methane emissions from the oil and gas industry, and the EPA also issued rules aimed at reducing methane emissions from the oil and gas industry.

But methane levels have risen faster over the past five years than at any other time on NOAA’s record. Xin Lan points out that much of the increase is due to microbes from wetlands, agriculture, and landfills, but not as much from the energy industry.

According to the Global Carbon Project, CO2 emissions into the air from burning fossil fuels and cement production hit an all-time high last year at 36.8 billion tonnes, double the amount released into the air 40 years ago.

However, about half of it is temporarily trapped by trees and oceans, preventing it from reaching the atmosphere. Methane does not have the ability to temporarily store carbon like CO2, Ms. Xin Lan said.

Last year, the shift from La Nina to El Nino contributed to a slowdown in the growth of methane in the atmosphere and a rise in CO2 concentrations. La Nina ended last year, giving way to a strong El Nino. Scientists say atmospheric CO2 concentrations tend to rise when El Nino is warmer.

Ngoc Anh (according to AP)

Source