Next 20 years could lock in Paris Agreement’s 1.5°C warming limit, warns study

Earth has likely entered a pivotal 20-year window where global temperatures will consistently approach the Paris Agreement’s 1.5°C limit—marking a critical period for climate action, risk management, and adaptation strategies, finds new study

Earth has officially reached a significant climate threshold. The year 2024 has been recorded as the first full calendar year where global temperature measurements indicate an average surpassing 1.5°C above pre-industrial levels, as reported by multiple climate monitoring agencies. According to a new study published in Nature Climate Change, this finding signals that Earth is most probably within the 20-year period that will reach the long-term warming limit outlined in the Paris Agreement.

A year above 1.5°C: What it means

The Paris Agreement set forth the goal of limiting global warming to well below 2°C, preferably to 1.5°C, compared to pre-industrial levels. However, this temperature target is not based on single-year fluctuations, but on a 20-year global average. The announcement that 2024 was the first full year exceeding 1.5°C does not mean that the Paris limit has officially been breached. It, however, serves as a strong indicator that the world has likely entered the 20-year period in which that limit will be reached.

Researchers say that while short-term natural variability, such as the presence of an El Niño event, can contribute to temporary spikes in temperature, human-induced climate change remains the primary cause of global warming. Observational data combined with climate model projections suggest that unless stringent mitigation actions are taken immediately, global temperatures will continue to rise, solidifying the 1.5°C threshold as a new climate reality rather than a passing anomaly.

Tracing the trends

The relationship between individual warm years and the onset of long-term warming levels has been studied through historical temperature trends and advanced climate models. According to the study, previous instances of global warming milestones—such as exceeding 0.6°C, 0.7°C, 0.8°C, 0.9°C, and 1.0°C—show a consistent pattern. These “global warming thresholds have consistently fallen within the first 20-year period in which average temperature reached the same thresholds”, the study states.

Analyses of past warming levels indicate that Earth is following a similar trajectory toward sustained 1.5°C warming. Researchers studied climate models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) and found that under current policy scenarios, once a single year surpasses 1.5°C, it is highly likely that the planet is within the two-decade window where the long-term average will stabilise at that level.

The way forward

While Earth’s temperature trajectory appears locked into a path that will solidify 1.5°C warming, there is still room for mitigation efforts to slow the rate of increase and minimise risks, according to the researchers. The study suggests that reducing global warming rates could significantly impact how soon and how far temperatures rise beyond this threshold.

The strong warming trends observed over the past decade, averaging approximately 0.026°C per year, indicate that without rapid emission reductions, surpassing the 1.5°C level for sustained periods is almost inevitable. However, stringent climate action, including deep emission cuts and shifts to low-carbon energy, could reduce warming trends to 0.005°C per year, potentially delaying or preventing prolonged exceedance of this critical threshold.

Call for urgent action

According to the study, crossing the 1.5°C warming level has significant implications for climate risk management and adaptation planning. Scientific research has extensively documented the increased climate hazards expected at this level, including intensified heatwaves, more frequent extreme weather events, rising sea levels, and biodiversity loss. Governments need to recognise and accept that Earth is now in a period of sustained 1.5°C warming. The need of the hour accelerating adaptation strategies, improving resilience, and strengthening climate action commitments, the study warns.

About The Author

Editorial Team

A team of handpicked and dedicated writers committed to fact check each climate-related statement. Go to the roots and intent of each policy implemented, internationally and at home to help you understand climate better

See author's posts