797. Global Warming Updates Over the Past Decade

On June 9, the Japan Meteorological Agency announced that an El Niño event appears to be underway and predicted that there is a 90% chance that the El Niño event will continue into the fall. The El Niño phenomenon will have a contrasting effect to the weather and climate patterns that La Niña has brought in recent years, and could push global temperatures even higher.

At the 28th Conference of the Parties (COP28) to the United Nations Framework Convention on Climate Change (UNFCCC), to be held in Dubai this December, scientific evidence will be important in making policy decisions to further strengthen climate action. In March this year, the Intergovernmental Panel on Climate Change (IPCC) released its Sixth Assessment Synthesis Report, which outlines the actions needed to curb global warming in accordance with the Paris Agreement.  However, the problem with IPCC reports is that they are released in 5-10 year cycles and therefore do not represent the most recent data.

Against this backdrop, a paper published in Earth System Science Data reports the latest information on temperature and greenhouse gas emission trends based on IPCC methodology. The paper shows that human-induced warming progressed at an unprecedented rate during the period 2013-2022, averaging 1.14 [0.9 to 1.4] °C over the 10-year period relative to the industrial revolution, and 1.26 [1.0 to 1.6] °C in 2022, a warming of 0.2 °C over 10 years. The paper attributes the warming over this period to a decrease in aerosols, which have a cooling effect, and to record greenhouse gas emissions of 54 billion metric tons of carbon dioxide equivalent. According to the paper, anthropogenic warming has reached an all-time high during this decade, and without the cooling effect of major eruptive activity, the possibility of reaching 1.5°C within a decade cannot be ruled out, while greenhouse gas emissions may peak and begin a downward trend. The paper emphasized the need to pursue the possibility that humanity could transform its anthropogenic impact on climate by making a societal choice to reduce greenhouse gas emissions in the 2020s.

With projections showing a high probability of exceeding the Industrial Revolution average temperature by 1.5°C in at least one year of the five-year period 2023-2027, a systemic transition is needed to reduce greenhouse gas emissions across all sectors.

Reference
Piers M. Forster et al., Indicators of Global Climate Change 2022: annual update of large-scale indicators of the state of the climate system and human influence, Earth System Science Data (2023). https://essd.copernicus.org/articles/15/2295/2023/

Contributor: IIYAMA Miyuki (Information Program)