In a concerning development, scientists predict that the world is on track to surpass the crucial 1.5°C global warming threshold within the next few years. With a 66% chance of breaching this limit by 2027, the increasing likelihood is attributed to human-induced emissions and anticipated changes in weather patterns this summer.
Exceeding the 1.5°C mark signifies a temperature increase compared to the latter half of the 19th Century, prior to the significant rise in fossil fuel emissions driven by industrialization. Even a temporary breach of this limit, though worrisome, highlights an acceleration of warming trends rather than a slowdown.
The 1.5°C threshold has become a symbolic target in global climate change negotiations since the 2015 Paris agreement, where countries committed to pursuing efforts to limit global temperature rises to that level. Sustained elevation above this limit for a decade or two would lead to more pronounced consequences such as longer heatwaves, intensified storms, and increased wildfire occurrences.
However, surpassing the threshold in the next few years does not necessarily mean that the Paris agreement’s limit has been broken. Scientists emphasize that there is still an opportunity to curb global warming by significantly reducing emissions.
Since 2020, the World Meteorological Organization has been assessing the chances of breaching the 1.5°C threshold in any given year. Initially, there was less than a 20% likelihood, which then increased to 50% by the previous year. The current estimation of 66% implies that surpassing the threshold is more likely than not.
While the 1.5°C figure is not an exact measurement of global temperature, it serves as an indicator of the extent of warming relative to the long-term global average. Scientists utilize average temperature data from the period between 1850 and 1900 as a benchmark for pre-industrial temperatures. The previous assumption was that 2°C of warming would be the threshold for dangerous impacts, but revised estimates in 2018 emphasized the calamitous consequences of surpassing 1.5°C.
Over the past few decades, global temperatures have risen steadily. In 2016, the warmest year on record, temperatures were 1.28°C above the pre-industrial figure. Researchers are now 98% certain that this record will be broken before 2027. Additionally, they foresee a solid chance of temporarily surpassing the 1.5°C limit for the first time in history.
While breaching the threshold temporarily would sound an alarm, maintaining temperatures at or above 1.5°C for 20 years would indicate a permanent shift beyond the Paris agreement’s specified limit. The World Meteorological Organization warns that temporary exceedances will occur with increasing frequency, highlighting the urgency of the situation.
Two key factors contribute to the heightened chances of crossing the threshold: ongoing carbon emissions from human activities and the anticipated occurrence of El Niño, a weather phenomenon with global implications. The past few years have experienced a La Niña event, which has dampened climate warming to some extent. However, the additional heat brought by El Niño to the Pacific Ocean’s surface is expected to push global temperatures to new highs.
While there is uncertainty surrounding the timing and magnitude of El Niño, forecasts suggest a significant impact. The Arctic region is projected to experience warming three times greater than the global average over the next five northern hemisphere winters. Northern Europe, including the United Kingdom, is anticipated to experience increased rainfall from May to September over the next five years.