New proposal for defining global warming levels in light of COP28

This revelation comes as COP28 is underway, emphasising the urgent need for clarity in understanding and responding to climate change.

Currently, global average temperatures for specific years are well-documented. However, these annual figures do not effectively indicate whether the Paris Agreement's goal of limiting warming to 1.5°C above pre-industrial levels is being breached, as the Agreement focuses on long-term trends rather than single-year anomalies. This lack of a standard metric could lead to confusion and delays in addressing climate change effectively.

Professor Richard Betts MBE, from the Met Office and the University of Exeter, and the paper's lead author, proposes a novel solution. He stresses the importance of clear guidelines: “Clarity on breaching the Paris Agreement guard rails will be crucial. Without an agreement on what actually will count as exceeding 1.5°C, we risk distraction and confusion at precisely the time when action to avoid the worst effects of climate change becomes even more urgent.”

To overcome this challenge, the team suggests using a combination of the average global temperature from the past decade and a projection for the upcoming ten years. This approach can provide a more immediate and accurate assessment of whether the 1.5°C threshold is being approached or exceeded.

Using this method, the current global warming level is approximately 1.26°C, with an uncertainty range of 1.13°C to 1.43°C. It also indicates a significant likelihood that one of the next five years could reach or surpass the 1.5°C mark.

Professor Betts highlights that relying solely on short-term data can be misleading due to natural climate variability. He suggests that a multi-year observation and projection model would better account for this variability and reveal the true extent of human-induced warming.

Preliminary estimates for 2023 suggest it could be the warmest year on record, potentially surpassing the high set in 2016. This trend continues the streak of record-breaking temperatures since 1850, emphasising the dominant role of human-induced greenhouse gas emissions in recent climate changes.

To support this new approach, the Met Office has added a section to its Climate Dashboard. This ‘Indicators of Global Warming’ dashboard displays eight separate indicators and observed global mean temperature using Met Office HadCRUT5 data. It also includes a comprehensive table explaining each indicator, providing a clear and accessible understanding of current global warming levels.

The introduction of this new metric and the updated Climate Dashboard represent a critical step in addressing the challenges of climate change. As the world watches for news from COP28, this development offers a more precise and actionable framework for evaluating and responding to global warming, thus contributing significantly to the global effort to mitigate climate change impacts.