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It is impossible to turn on the news or read a newspaper these days without being confronted with catastrophic natural disasters (wildfires, droughts, floods, etc.) throughout the world. The world’s top scientists are telling us that climate change is not something that will happen in the future. It is here now and it will affect all of us, but those who are marginalized and economically poor will suffer disproportionately, and yet, they have done little to contribute to the causes of climate change.

According to the August 9, 2021 release of a report from Working Group I Climate Change 2021: the Physical Science Basis, of the Intergovernmental Panel on Climate Change (IPCC), “Scientists are observing changes in the Earth’s climate in every region and across the whole climate system. Many of the changes observed in the climate are unprecedented in thousands, if not hundreds of thousands of years, and some of the changes already set in motion—such as continued sea-level rise—are irreversible over hundreds to thousands of years.”

Established by the World Meteorological Society and the United Nations Environment Programme in 1988, the IPCC’s mandate is “to provide the world with a clear scientific view on the current state of knowledge in climate change and its potential environmental and socio-economic impacts.” The entire Sixth Assessment Report will be released in 2022. This report alone involved a total of 78,007 expert and government review comments. The other two IPCC working groups are Working Group II, dealing with impacts, adaptation, and vulnerability; and Working Group III, dealing with the mitigation of climate change

The Working Group I report addresses the most updated physical understanding of the climate system and climate change, bringing together the latest advances in climate science, and combining multiple lines of evidence from paleoclimate, observations, process understanding, global and regional climate simulations. It shows how and why climate has changed to date, and the improved understanding of human influence on a wider range of climate characteristics, including extreme events.

“Climate change is already affecting every region on Earth, in multiple ways. The changes we experience will increase with additional warming,” said IPCC Working Group I Co-Chair Panmao Zhai. The report projects that in the coming decades climate changes will increase in all regions. For 1.5°C of global warming, there will be increasing heat waves, longer warm seasons, and shorter cold seasons. At 2°C of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health, the report shows. But it is not just about temperature. Climate change is bringing multiple different changes in different regions – which will all increase with further warming.

These include changes to wetness and dryness, to winds, snow and ice, coastal areas, and oceans. For example:

• Climate change is intensifying the water cycle. This brings more intense rainfall and associated flooding, as well as more intense drought in many regions.
• Climate change is affecting rainfall patterns. In high latitudes, precipitation is likely to increase, while it is projected to decrease over large parts of the subtropics. Changes to monsoon precipitation are expected, which will vary by region.
• Coastal areas will see continued sea-level rise throughout the 21st century, contributing to more frequent and severe coastal flooding in low-lying areas and coastal erosion. Extreme sea-level events that previously occurred once in 100 years could happen every year by the end of this century.
• Further warming will amplify permafrost thawing, and the loss of seasonal snow cover, melting of glaciers and ice sheets, and loss of summer Arctic sea ice.
• Changes to the ocean, including warming, more frequent marine heatwaves, ocean acidification, and reduced oxygen levels have been clearly linked to human influence. These changes affect both ocean ecosystems and the people that rely on them, and they will continue throughout at least the rest of this century.
• For cities, some aspects of climate change may be amplified, including heat (since urban areas are usually warmer than their surroundings), flooding from heavy precipitation events, and sea-level rise in coastal cities.

 For the first time, this contribution to the Sixth Assessment Report provides a more detailed regional assessment of climate change, including a focus on useful information that can inform risk assessment, adaptation, and other decision-making, and a new framework that helps translate physical changes in the climate – heat, cold, rain, drought, snow, wind, coastal flooding and more – into what they mean for society and ecosystems.

For more information go to: http://www.ipcc.ch/

August 12, 2021