The Met Office of Britain predicted on Friday that the increased levels of carbon dioxide in the atmosphere this year will surpass crucial trajectories aimed at limiting warming to 1.5 degrees Celsius. Researchers emphasized that only substantial cuts in emissions can help maintain the targeted limit. The surge in emissions from fossil fuels and deforestation is expected to be further intensified in 2024 by the cyclical El Nino weather phenomenon, diminishing the capacity of tropical forests to absorb carbon.
The Met Office forecasts a “relatively large” increase in the annual average CO2 concentrations measured at the Mauna Loa Observatory in Hawaii for this year, estimating it to be around 2.84 parts per million (ppm) higher than in 2023. Researchers cautioned that this trajectory is likely to deviate from the primary pathways outlined by the UN’s Intergovernmental Panel on Climate Change (IPCC) for limiting warming to 1.5 degrees Celsius, a more ambitious goal set by the 2015 Paris Agreement.
Richard Betts, the Met Office author of the CO2 forecast, expressed skepticism about achieving the 1.5-degree target, stating, “It’s looking vanishingly unlikely that we’ll limit warming to 1.5.” He noted that while it is technically possible with immediate drastic emissions reduction, the scenarios outlined by the IPCC indicate a slowdown in CO2 buildup in the atmosphere to meet the specified target. Scientists caution that the world is approaching instances of individual years with warming exceeding 1.5C, even though it does not, in itself, constitute a breach of the Paris target, which is assessed over an average of approximately two decades.
The IPCC has previously warned that if current emission levels persist, the world is likely to surpass the 1.5-degree Celsius threshold in the early 2030s. Richard Betts noted, “We’re not seeing any signs of avoiding that in terms of the buildup of CO2 in the atmosphere.” The World Meteorological Organization, affiliated with the UN, recently affirmed that 2023 set a record as the warmest year by a substantial margin, with the annual average global temperature standing at 1.45 degrees Celsius above pre-industrial levels (1850-1900).
There is concern that this year might experience even higher temperatures due to the emergence of the naturally occurring El Nino climate pattern in mid-2023, which typically leads to an increase in global temperatures for the following year.
El Nino introduces hotter and drier conditions to tropical forests and peatlands, diminishing their capacity to absorb carbon from the atmosphere. Typically, approximately half of human emissions are reabsorbed by ecosystems and ocean absorption. “That free service is weakened when there’s an El Nino happening, so that means more of our emissions are staying in the atmosphere this year,” explained Richard Betts. Regions like the Amazon, already grappling with severe drought, heat, and fires, face heightened concerns.
UN experts emphasize the necessity of nearly halving emissions in this decade to uphold the 1.5-degree Celsius limit. Despite this, carbon pollution continues to rise. Mauna Loa, monitoring atmospheric CO2 levels since 1958, has observed a generally upward trend in CO2 levels. The Met Office utilizes emissions data, along with observations and forecasts of ocean surface temperatures in the equatorial east Pacific—an El Nino indicator—to predict CO2 concentrations at Mauna Loa, considered representative of global averages.
Betts noted that even without the El Nino effect, the estimated CO2 buildup in the atmosphere would be at the “very, very upper limit of consistency” with the IPCC 1.5-degree scenarios. Stressing that there are multiple approaches to maintain the 1.5-degree limit, he emphasized that all viable paths involve “urgent emissions cuts.”