The United Nations has issued a stark warning that the upcoming five years are on track to become the warmest period ever recorded. A combination of greenhouse gas emissions and the anticipated El Niño phenomenon is expected to drive temperatures to unprecedented heights. For the first time, there is a greater likelihood than not that global temperatures will surpass the critical threshold of 1.5 degrees Celsius (2.7 degrees Fahrenheit) of warming by 2027, as declared by the World Meteorological Organization.
The 1.5C Threshold: A Symbol of Climate Change Negotiations
The 1.5C threshold represents the level at which the world’s average temperature exceeds that of the second half of the 19th century, prior to the significant increase in fossil fuel emissions associated with industrialisation. Surpassing this limit, even for a single year, serves as an alarming indication of accelerating warming trends. The figure has become symbolic in global climate change negotiations, with countries agreeing to “pursue efforts” to limit global temperature rises to 1.5C under the 2015 Paris Agreement. Consistently exceeding this limit for a decade or two would result in heightened impacts, such as prolonged heatwaves, intensified storms, and increased wildfire frequency.
Chances of Surpassing 1.5C: Assessing the Risk
The World Meteorological Organisation has been monitoring the likelihood of surpassing the 1.5C threshold since 2020. Initially, the chances were estimated to be less than 20% within the following five years. However, this estimate has steadily risen over time, reaching 50% last year and currently standing at 66%. This increase signifies that surpassing the 1.5C limit is now more probable than not. Nevertheless, it is important to note that breaching this threshold in the next few years does not imply a permanent violation of the Paris Agreement. Experts emphasise that there is still an opportunity to limit global warming by significantly reducing emissions.
Understanding the Significance of Exceeding 1.5C
The 1.5C threshold serves as an indicator of the extent to which the Earth’s temperature has deviated from the long-term global average. Scientists utilise temperature data from the period between 1850 and 1900 as a baseline for comparison, representing the pre-industrial era before the widespread reliance on coal, oil, and gas. While the scientific community previously believed that a 2C increase would be the threshold for dangerous impacts, recent revisions have demonstrated that surpassing 1.5C would already have calamitous consequences. In 2016, which was the warmest year on record, global temperatures exceeded the pre-industrial figure by 1.28C. Researchers now assert with 98% certainty that this record will be broken before 2027.
El Niño and Its Role in Escalating Temperatures
Two factors contribute significantly to the likelihood of exceeding the 1.5C threshold: continuously high carbon emissions from human activities and the potential emergence of an El Niño event. Despite a temporary reduction in emissions during the pandemic, overall emissions continue to rise. El Niño, a weather phenomenon with global implications, could exacerbate the situation further. Over the past three years, a La Niña event has somewhat dampened climate warming. However, the additional heat brought by an El Niño event could push global temperatures to new highs. While there is still uncertainty surrounding the timing and scale of the El Niño event, scientists are closely monitoring its development and potential impacts.
Professor Adam Scaife, head of long-range forecasts at the Met Office, acknowledges the significance of El Niño in this context. He explains that the forecasts for the upcoming El Niño event suggest a substantial amplitude, indicating a potentially notable increase in temperatures. However, predicting the exact magnitude and subsequent events beyond the coming year remains challenging. It is plausible that a strong El Niño event, perhaps two and a half degrees, could occur in the next three or four years and be the catalyst for surpassing the 1.5C threshold.
Urgency of Action
To mitigate the risk of long-term warming exceeding the 1.5C limit, global efforts to reduce greenhouse gas emissions must be intensified. Transitioning to renewable energy sources, improving energy efficiency, and adopting sustainable practices across industries are crucial steps in curbing emissions. Additionally, investing in climate adaptation strategies, such as resilient infrastructure and ecosystem restoration, can help mitigate the impacts of a changing climate.
The urgency to act is underscored by the narrowing window of opportunity to limit global warming. While temporary exceedances are alarming, they also serve as a wake-up call for governments, businesses, and individuals to prioritise climate action. The goals of the Paris Agreement, including limiting global temperature rise to well below 2C and pursuing efforts to reach 1.5C, require immediate and concerted action on a global scale.