WMO Update: 50-50 Chance of Global Temperature Temporarily Reaching 1.5°C Threshold in Next Five Years

A new climate update from the World Meteorological Organization (WMO) indicates a 50% probability that the annual average global temperature will temporarily reach 1.5°C above pre-industrial levels at least once in the next five years. This probability is increasing over time.

There is a 93% likelihood that at least one year between 2022 and 2026 will surpass 2016 as the warmest year on record. Additionally, the chance that the five-year average temperature for 2022-2026 will exceed that of 2017-2021 is also 93%, according to the Global Annual to Decadal Climate Update. This report is produced by the United Kingdom’s Met Office, which serves as the WMO’s lead center for such predictions.

The annual update utilizes the expertise of leading climate scientists and advanced prediction models from global climate centers to provide critical information for policymakers.

Since 2015, when the likelihood of temporarily exceeding 1.5°C was close to zero, this probability has steadily increased. Between 2017 and 2021, the chance of surpassing this threshold was 10%. That probability has now risen to nearly 50% for the period from 2022 to 2026.

According to WMO Secretary-General Prof. Petteri Taalas, the report demonstrates, with high scientific confidence, that the world is approaching the lower target set by the Paris Agreement on Climate Change. The 1.5°C threshold is a key marker, indicating a point at which climate impacts are expected to become increasingly severe for ecosystems and human societies alike.

Prof. Taalas emphasized that continued greenhouse gas emissions will drive ongoing temperature increases, leading to further ocean warming and acidification, melting sea ice and glaciers, rising sea levels, and more extreme weather events. Arctic warming remains disproportionately high, with global consequences.

The Paris Agreement establishes long-term objectives to significantly reduce global greenhouse gas emissions, aiming to limit temperature increases in this century to 2°C while making efforts to keep the rise below 1.5°C.

The Intergovernmental Panel on Climate Change (IPCC) states that climate-related risks to natural and human systems are greater at 1.5°C of warming compared to present conditions but remain lower than those expected at 2°C.

Dr. Leon Hermanson of the Met Office, who led the report, noted that projections confirm the ongoing global temperature increase, with an even chance that one year between 2022 and 2026 will exceed 1.5°C above pre-industrial levels. While a single year exceeding this threshold would not indicate a permanent breach of the Paris Agreement target, it underscores the increasing likelihood that temperatures will remain above 1.5°C for extended periods.

In 2021, the global average temperature was recorded at 1.1°C above the pre-industrial baseline, as noted in WMO's provisional State of the Global Climate report. The final report for 2021 was scheduled for release on 18 May.

The cooling effect of back-to-back La Niña events at the beginning and end of 2021 did not counteract the long-term warming trend. Any development of an El Niño event would likely drive temperatures higher, as was the case in 2016, the warmest year on record.

Key Findings from the Annual Update:

• The global near-surface temperature for each year between 2022 and 2026 is projected to range between 1.1°C and 1.7°C above pre-industrial levels (based on the 1850-1900 average).
• The probability of at least one year between 2022 and 2026 exceeding 1.5°C above pre-industrial levels is estimated at 48%. However, the chance of the five-year average exceeding this threshold remains low at 10%.
• The likelihood that at least one year between 2022 and 2026 will surpass 2016 as the warmest year on record is 93%.
• The probability that the five-year mean temperature for 2022-2026 will exceed that of 2017-2021 is also 93%.
• The Arctic region is expected to experience warming more than three times the global mean anomaly when averaged over the next five northern hemisphere extended winters.
• No clear signal has been identified for the El Niño Southern Oscillation (ENSO) for December-February 2022/23, although a positive Southern Oscillation Index is projected for 2022.
• Predicted precipitation trends for 2022, relative to the 1991-2020 average, indicate a higher likelihood of drier conditions in southwestern Europe and southwestern North America. Wetter conditions are expected in northern Europe, the Sahel, northeastern Brazil, and Australia.
• From May to September between 2022 and 2026, precipitation patterns suggest increased rainfall in the Sahel, northern Europe, Alaska, and northern Siberia, while drier conditions are likely over the Amazon.
• From November to March between 2022/23 and 2026/27, precipitation patterns are expected to show increased rainfall in the tropics and reduced rainfall in the subtropics, aligning with expected climate warming trends.