On the 9th of August 2021, the Intergovernmental Panel on Climate Change (IPCC) released its sixth assessment report on climate change. As with previous reports, it confirms that human activity is directly responsible for global warming, and that without immediate drastic action we stand very little chance of limiting warming to 1.5°C. This is the most up-to-date report on the climate system and climate change, with 234 authors from 66 different countries, bringing together the work of over 14,000 publications.
The report contains a comprehensive review of the impacts of climate change around the world so far, including changes to the atmosphere, ocean, ice coverage, and ecosystems, as well as weather extremes such as heatwaves, heavy rainfall, droughts, and cyclones. The extent of global warming has been more intense over the land than the oceans, and twice as high in the Arctic. The report also uses scientific knowledge of climate processes and data on historic and prehistoric climates (paleoclimates) to predict what the current climate should be without the influence of human processes (Figure 1), unequivocally demonstrating that the observed rise of 1.1°C in average global temperature since 1850-1900 is caused by human activity.
Progress in the study of climate processes and paleoclimates have also allowed the authors of the report to create the most accurate predictions so far of potential climate futures, ranging from somewhat hopeful to bluntly apocalyptic. It demonstrates how the impacts of climate change, such as Arctic sea-ice loss, ocean acidification, and sea-level rise can be stabilised or intensified in different scenarios (Figure 2). It also confirms that immediate, large-scale reductions in emissions of carbon dioxide and other greenhouse gases are needed to have a chance of limiting warming to 1.5°C or even 2°C, and to reduce the worst of the impacts of climate change. The report predicts that 1.5°C will be reached or exceeded in the next 20 years in every scenario, but we can avoid exceeding this, and even eventually reduce this, with rapid, widespread action now.
Ultimately, the IPCC report highlights a truth that many are already well aware of: the planet is warming due to human activity, and this has already begun to cause a great deal of changes around the world. For many of the people involved in the Climate Justice for All campaign, climate change is a lived reality, whether that be droughts in Zambia, sea-level rise in Fiji or cyclones in India. People are suffering, and even more will suffer as the planet continues to warm. COP26 may provide hope for us all, but only if countries agree to make the drastic changes recommended by the IPCC report. Only then can we begin to repair our broken planet.
Masson-Delmotte, Valérie; Zhai, Valérie; Pirani, Anna; Connors, Sarah L; Péan, Clotilde; Berger, Sophie; Caud, Nada; Chen, Yang; Goldfarb, Leah; Gomis, Melissa I; Huang, Mengtian; Leitzell, Katherine; Lonnoy, Elizabeth; Matthews, JB Robin; Maycock, Tom K; Waterfield, Tim; Yelekçi, Özge; Yu, Rong; Zhou, Baiquan, eds. (7 August 2021). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (PDF). Geneva, Switzerland: Intergovernmental Panel on Climate Change (IPCC).