A Milestone in Climate Change: The First Year of Global Warming Above 1.5 Degrees Celsius

The world has reached a significant milestone in its ongoing battle against climate change. For the first time in recorded history, global warming has exceeded 1.5 degrees Celsius for an entire year. This development, reported by the European Union’s climate service, is a stark reminder of the urgent need for action to limit the long-term temperature rise and avoid the most damaging impacts of climate change.

The Paris Agreement, signed in 2015, set a goal for the international community to limit the long-term temperature rise to 1.5 degrees Celsius above pre-industrial levels. This target is crucial as it is believed that the risks of climate change, such as intense heatwaves, rising sea levels, and loss of wildlife, are much higher at 2 degrees Celsius of warming than at 1.5 degrees Celsius. However, the first year-long breach of this target does not break the Paris Agreement but brings the world closer to crossing it in the long term.

Professor Liz Bentley, the chief executive of the Royal Meteorological Society, commented on the significance of this development, stating, “To go over 1.5 degrees of warming on an annual average is significant. It’s another step in the wrong direction. But we know what we’ve got to do.”

Limiting long-term warming to 1.5 degrees Celsius above pre-industrial levels has become a key symbol of international efforts to tackle climate change. A landmark UN report in 2018 highlighted the importance of this target, stating that the risks from climate change are much higher at 2 degrees Celsius of warming than at 1.5 degrees Celsius.

The past year has seen temperatures continue to rise at a concerning pace, with the EU’s Copernicus Climate Change Service reporting that the period from February 2023 to January 2024 reached an average temperature of 1.52 degrees Celsius. This is a significant increase from the 0.2 degrees Celsius warming seen in the 1940s.

While this year-long breach of the 1.5-degree Celsius target is no major surprise, given that January was the eighth record-warm month in a row, it is a worrying development that underscores the need for urgent action to reduce carbon emissions and limit warming.

Professor Myles Allen, a lead author of the UN’s landmark 2018 report and a researcher at the University of Oxford, emphasized the importance of rapid reductions in greenhouse gas emissions to prevent further warming. He stated, “Rapid reductions in greenhouse gas emissions are the only way to stop global temperatures increasing.”

The long-term warming trend is being driven primarily by human activities, particularly the burning of fossil fuels, which releases planet-warming gases like carbon dioxide. In recent months, a natural climate-warming phenomenon known as El Niño has also given air temperatures an extra boost, although it typically only does so by about 0.2 degrees Celsius.

Global average air temperatures began exceeding 1.5 degrees Celsius of warming on an almost daily basis in the second half of 2023, when El Niño began kicking in, and this has continued into 2024. An end to El Niño conditions is expected in a few months, which could allow global temperatures to temporarily stabilize and then fall slightly, probably back below the 1.5-degree Celsius threshold. However, human activities mean that temperatures will ultimately continue rising in the decades ahead unless urgent action is taken.

The Paris Agreement goal of limiting warming to 1.5 degrees Celsius as a long-term average, rather than a single year, could be crossed within the next decade at the current rate of emissions. This would be a hugely symbolic milestone, but researchers say it wouldn’t mark a climate cliff edge. The impacts of climate change would continue to accelerate, and every tenth of a degree of warming causes more harm than the last one. An extra half a degree, the difference between 1.5 degrees Celsius and 2 degrees Celsius of global warming, also greatly increases the risks of passing tipping points within the climate system, which could lead to rapid and potentially irreversible changes.

Despite the concerning developments, there is still hope that humans can make a difference to the world’s warming trajectory. The world has made some progress, with green technologies like renewables and electric vehicles booming in many parts of the world. This has meant that some of the very worst case scenarios of 4 degrees Celsius warming or more this century, which were considered possible a decade ago, are now considered much less likely based on current policies and pledges. And perhaps most encouragingly, it is still thought that the world will more or less stop warming once net zero carbon emissions are reached. Effectively halving emissions this decade is seen as particularly crucial.

In conclusion, the first year of global warming above 1.5 degrees Celsius is a significant milestone that underscores the urgent need for action to limit the long-term temperature rise and avoid the most damaging impacts of climate change. Rapid reductions in greenhouse gas emissions are the only way to prevent further warming and ultimately control how much warming the world experiences. The choices we make as a society and as a planet will determine the future of our planet and the lives of future generations.