Climate change widespread, rapid and intensifying: IPCC
According to the latest report by the Intergovernmental Panel on Climate Change (IPCC), scientists are observing changes in the earth’s climate in every region and in the entire climate system. Many of the climatic changes observed have been unprecedented for thousands, if not hundreds of thousands of years, and some of the changes already in motion – such as the sustained rise in sea levels – are irreversible for hundreds to thousands of years.
A strong and sustainable reduction in carbon dioxide emissions (CO2) and other greenhouse gases would limit climate change. While air quality would improve rapidly, it could take 20 to 30 years for global temperatures to stabilize, according to the report by IPCC Working Group I. Climate change 2021: the physical-scientific basis, which was approved by 195 member governments of the IPCC on Friday through a virtual approval meeting held over two weeks from July 26th.
Working group I reports is the first edition of the Sixth Assessment Report (AR6) of the IPCC, which will be completed in 2022.
“This report reflects extraordinary efforts in extraordinary circumstances,” said Hoesung Lee, chairman of the IPCC. “The innovations in this report and the advances in climate science it contains make an invaluable contribution to climate negotiations and decisions.”
The report includes new estimates of the chances of exceeding global warming levels of 1.5 ° C in the next few decades, and notes that unless one does, warming will be limited to close to 1.5 ° C immediate rapid and large-scale reductions in greenhouse gas emissions or even 2 ° C are unattainable.
The report shows that greenhouse gas emissions from human activities have been responsible for around 1.1 ° C of warming since 1850-1900, and notes that global temperature is projected to average 1.5 ° C over the next 20 years or will exceed. This assessment is based on improved observational datasets used to assess historical warming, as well as advances in scientific understanding of the climate system’s response to man-made greenhouse gas emissions.
“This report is a reality check,” said IPCC Working Group I Co-Chair Valérie Masson-Delmotte. “We now have a much clearer picture of past, present and future climates, which is essential to understanding where we are going, what can be done and how we can prepare.”
Every region is facing increasing changes
Many characteristics of climate change are directly related to the extent of global warming, but what people experience is often very different from the global average. For example, the warming over the land is greater than the global average and in the Arctic more than twice as high.
“Climate change is already affecting every region of the world in a variety of ways. The changes we are seeing will increase with additional warming, ”said IPCC Working Group I Co-Chair Panmao Zhai.
The report predicts that climate change will increase in all regions in the coming decades. With global warming of 1.5 ° C, there will be increasing heat waves, longer warm seasons and shorter cold seasons. With global warming of 2 ° C, heat extremes would more often reach critical tolerance levels for agriculture and health, the report shows.
But it’s not just about temperature. Climate change brings with it several different changes in different regions – all of which will increase with further warming. These include changes in wetness and drought, wind, snow and ice, coastal areas and oceans. For example:
- Climate change intensifies the water cycle. This brings with it more intense precipitation and associated floods as well as more intense droughts in many regions.
- Climate change affects precipitation patterns. Precipitation is likely to increase in high latitudes, while it is expected to decrease in large parts of the subtropics. Changes in monsoon precipitation are expected, which vary by region.
- In coastal areas, sea level increases during the 21st Extreme sea level events that previously occurred once in 100 years could occur every year until the end of this century.
- Further warming will intensify the thawing of permafrost and the loss of seasonal snow cover, the melting of glaciers and ice sheets, and the loss of Arctic sea ice in summer.
- Changes in the ocean, including warming, increased ocean heat waves, ocean acidification, and reduced oxygen levels, have been clearly linked to human impact. These changes are affecting both ocean ecosystems and the people who depend on them, and they will continue for at least the rest of this century.
- For cities, some aspects of climate change can be amplified, including heat (as urban areas are usually warmer than their surroundings), flooding due to heavy rainfall, and sea level rise in coastal cities.
For the first time, the Sixth Assessment Report provides a more detailed regional assessment of climate change, including an emphasis on useful information that can be used as a basis for risk assessment, adaptation and other decision-making, as well as a new framework to help monitor physical changes in climate – heat, Cold, rain, drought, snow, wind, coastal floods and more – in their significance for society and ecosystems.
This regional information can be examined in detail in the newly developed Interactive Atlas https://interactive-atlas.ipcc.ch/ as well as in regional fact sheets, the technical summary and the underlying report.
Human impact on past and future climate
“It has been clear for decades that the earth’s climate is changing, and the role of human influence on the climate system is undisputed,” said Masson-Delmotte. However, the new report also reflects major advances in the science of attribution – understanding the role of climate change in intensifying certain weather and climatic events, such as extreme heat waves and heavy rain events.
The report also shows that human action still has the potential to determine the future course of the climate. There is strong evidence that carbon dioxide (CO2) is the main driver of climate change, although other greenhouse gases and air pollutants also affect the climate.
“The stabilization of the climate requires a strong, rapid and sustainable reduction in greenhouse gas emissions and the achievement of net CO emissions2 Emissions. Limiting other greenhouse gases and air pollutants, particularly methane, could be beneficial for both health and the climate, ”said Zhai.
– This press release was originally posted on the Intergovernmental Panel on Climate Change (IPCC) website