Super El Niño could push CO2 levels to record highs in 2027 - with devastating consequences, Met Office warns

An exceptionally strong El Niño could drive CO2 levels in the atmosphere to record highs in 2027, the Met Office has warned. El Niño amplifies human sources of emissions while also making it harder for the planet to absorb those greenhouse gases. Now, as we brace for the strongest El Niño in a millennium, experts are expecting a similarly historic surge in CO2. Climate forecasts predict that the concentration of CO2, as recorded at the Mauna Loa Observatory in Hawaii , will rise by around 3.51 parts per million (ppm) next year.

That is the largest year-on-year increase ever forecast by the Met Office, and rivals the record increase recorded in 2024 when exceptional wildfires boosted emissions . If this forecast is accurate, it would bring the total atmospheric concentration to a record-breaking 432.2 ppm. That could make it significantly harder for the world to keep global warming below the 1.5°C threshold set out in the Paris Agreement, with potentially devastating consequences.

An exceptionally strong El Niño could drive CO2 levels in the atmosphere to record highs in 2027, the Met Office has warned El Niño is part of a natural climate cycle called the El Niño Southern Oscillation, which shifts between hot and cold – El Niño and La Niña – phases once every two to seven years. During the El Niño part of the cycle, the trade winds in the Pacific Ocean, which normally blow warm water westwards towards Australia, slow or even reverse.

This leads to a build-up of warm waters in the Equatorial Pacific off the coast of South America, leading to severe weather disruption and above-average global temperatures. Recently, experts from the Met Office warned that this would lead to deadly storms and winter chaos in the UK. The powerful weather phenomenon threatens to unleash fierce winds, torrential rain and even snow across the UK over the next few months. These intense storms, and potentially snowy winters, could make it difficult for some people to get to work or even leave their homes.

However, El Niño conditions also lead to significant increases in global CO2 concentrations. Met Office scientist Emily Wright, who worked on the forecast, says: 'Human emissions are still driving the long-term increase, but plants, soils and oceans normally absorb some of the CO2 we release. 'El Niño events reduce how much they absorb overall, leaving more CO2 in the atmosphere.' This is because El Niño typically brings hot, dry weather over the tropical land regions.

In these areas of Central America, West Pacific nations and tropical South America, CO2 is sucked into vast carbon sinks, such as the Amazon Rainforest. This comes as forecasters predict that the strongest El Niño event in a millennium will reach its peak in December and into early 2027, driving an increase in greenhouse gases by reducing the ability of vegetation to absorb CO2 Drought, dry vegetation, and wildfires all interfere with the planet's natural ability to store carbon and offset human-caused emissions.

At the same time, exceptionally hot weather creates more demand for energy as people run air-conditioning systems for longer to stay cool, leading to more emissions. However, although El Niño is expected to make things worse, experts insist that the most significant driver of record emissions is human activity. Professor Richard Betts, Head of Climate Impacts Research in the Met Office Hadley Centre, says: 'Natural climate variability can substantially alter annual rates of CO2 rise, particularly during strong El Niño events.

But behind this year-on-year variability is the long-term trend from human-caused emissions. 'To follow pathways consistent with limiting warming to 1.5°C, the underlying rate of CO2 increase needs to slow substantially, but this forecast shows that the rate of rise remains too high.' Scientists don't expect that extra CO2 to have an effect on next year's weather, but the implication is that long-term warming will continue for years to come.

Professor Betts told the Daily Mail: 'We don’t expect immediate impacts on the UK from this additional CO2 rise, but the fact that the world can no longer limit global warming to 1.5C means that in the coming years and decades the UK will continue to experience more extreme weather and impacts such as droughts, floods, fires and sea level rise.' This comes after data showed greenhouse gas emissions have now hit an all-time high, with CO2 growth rates tripling since 1960 (right) Meanwhile, a new tool, called the El Niño Heat Mortality Tracker , reveals that an extra 370,000 lives could be at risk over the next six months .

Nigeria, India and Brazil are forecast to bear the brunt of the crisis, accounting for more than a third of projected heat deaths by March. The UK is also affected, the map shows, with an estimated 820 deaths already attributable to El Niño's heat this summer. Likewise, additional warming is expected to increase the risk of powerful storms and extreme weather events. This comes after the World Meteorological Organisation reported that greenhouse gas emissions have already hit an all-time high, with CO2 growth rates tripling since 1960.

Despite countries around the world making commitments to pursue green policies and Net Zero targets, the amount of CO2, methane and nitrous oxide being put into the atmosphere has only increased. Nigeria, India and Brazil are forecast to bear the brunt of the crisis, accounting for more than a third of upcoming projected heat deaths by March Since the 1960s, CO2 growth rates have accelerated from 0.8ppm per year to 2.4ppm per year in the decade between 2011 and 2020.

However, from 2024 to 2025, the global average concentration of CO2 increased by 2.8 parts per million (ppm), only slightly less than the exceptional surge seen from 2023 to 2024. That brought concentrations of the greenhouse gas to an atmospheric concentration of 426.8 parts per million by the end of 2025, or 153 per cent of the pre-industrial baseline. Since CO2 can linger in the atmosphere for an extremely long time, experts warned that this has 'locked in' years more warming – even if emissions did rapidly decline.

Professor Joeri Rogelj, a climate scientist from Imperial College London, told the Daily Mail: 'Last year's summer alone, the UK saw over 1,500 heat-related deaths, and damages from wildfires, tropical cyclones and other extreme weather have been estimated to add up to over 100 billion USD. 'Reducing greenhouse gas pollution will reduce the climate risks that we are imposing onto the UK or the world of the 2030s and beyond.' THE PARIS AGREEMENT: A GLOBAL ACCORD TO LIMIT TEMPERATURE RISES THROUGH CARBON EMISSION REDUCTION TARGETS The Paris Agreement, which was first signed in 2015, is an international agreement to control and limit climate change.

It hopes to hold the increase in the global average temperature to below 2°C (3.6ºF) 'and to pursue efforts to limit the temperature increase to 1.5°C (2.7°F)'. It seems the more ambitious goal of restricting global warming to 1.5°C (2.7°F) may be more important than ever, according to previous research which claims 25 per cent of the world could see a significant increase in drier conditions. The Paris Agreement on Climate Change has four main goals with regards to reducing emissions: 1) A long-term goal of keeping the increase in global average temperature to well below 2°C above pre-industrial levels 2) To aim to limit the increase to 1.5°C, since this would significantly reduce risks and the impacts of climate change 3) Governments agreed on the need for global emissions to peak as soon as possible, recognising that this will take longer for developing countries 4) To undertake rapid reductions thereafter in accordance with the best available science Source: European Commission