IPCC climate report is released the
highest temperature reduction in the earth's temperature in 120,000 years, action brooks no delay
The first part of the sixth assessment report of the United Nations Intergovernmental Panel on Climate Change (IPCC), "Climate Change 2021: Natural Science Basis", was released on August 9.
This report is the first global assessment of global warming since 2013.
According to the report, the greenhouse gases produced by modern society’s continued dependence on fossil fuels are warming the world at an unprecedented rate in the past 2000 years. The impact of this is already obvious: record-breaking droughts, wildfires and floods have destroyed all parts of the world. .
If greenhouse gas emissions continue, the situation may get worse.
The report makes it clear that the future of the earth depends to a large extent on the choices made by human beings today.
"If we don't take action, the situation will become very bad," said Zhang Xuebin, a climatologist with Environment Canada, one of the main collaborators of the report.
Global warming may reach a critical value of 1.5℃ in the next 20 years
According to the "Paris Agreement" adopted in 2015, the international community agreed to limit the global temperature rise this century to less than 2.0°C higher than the pre-industrial level, and strive to limit the temperature rise to 1.5°C.
If this critical value is broken, phenomena such as the loss of Arctic sea ice, the mass extinction of coral reefs, and the melting of methane-rich permafrost will be more likely to occur, and the earth's ecosystem will undergo permanent transformation.
The report made a new estimate of the possibility of global warming in the coming decades.
According to the report, during the ten years from 2011 to 2020, the global surface temperature was 1.09°C higher than that during the period from 1850 to 1900. This is a level that has not been seen since the ice age 125,000 years ago. The past 5 years have also been recorded since 1850. The hottest five years.
From the average level of the next 20 years, scientists predict that by the mid-1930s, the temperature rise will reach or exceed 1.5°C.
The report predicts that climate change in all regions will intensify in the coming decades.
With a global warming of 1.5°C, the heat wave will become stronger, the warm season will be longer, and the cold season will be shorter.
The report shows that when global warming is 2.0°C, extreme high temperatures are more likely to reach the tolerance threshold for agriculture and health.
Increased water cycle, sea level rise... Changes vary in many places
According to the report, climate change is bringing many different changes to different regions, and these changes will intensify as global warming further intensifies.
These changes include wet and dry, wind, snow and ice, coastal areas and changes in the ocean.
According to the report, climate change is exacerbating the water cycle.
This has brought stronger rains and floods, and many areas are facing more severe droughts.
Climate change is affecting rainfall patterns.
It is expected that precipitation will increase in high latitudes, while precipitation will decrease in most of the subtropical regions.
The changes in monsoon precipitation are expected to vary from place to place.
Throughout the 21st century, sea levels in coastal areas will continue to rise.
Even if the temperature rise is maintained within the range of 1.5°C, it is expected that in the next 2000 sea levels will rise by 2-3 meters around the world; if the temperature rises by 2°C, the sea level will rise by as much as 6 meters.
This will lead to more frequent and severe coastal flooding and coastal erosion in low-lying areas.
By the end of this century, extreme sea-level events that have occurred once in a century may occur every year.
Changes in the ocean include warming, more frequent ocean heat waves, ocean acidification, and decreased oxygen levels.
These changes affect both marine ecosystems and people who depend on them, and these changes will continue for at least the rest of this century.
Further warming will also exacerbate the melting of permafrost, the reduction of seasonal snow cover, the melting of glaciers and ice caps, and the loss of Arctic sea ice in summer.
In addition, for cities, certain aspects of climate change may be amplified, including high temperatures (because urban areas are usually warmer than surrounding areas), floods caused by heavy precipitation events, and sea level rise in coastal cities.
It's not too late to change irreversible action
The report warns that some of the most serious effects of climate warming cannot be ruled out, such as the collapse of ice sheets, the disappearance of large-scale forests, or sudden changes in ocean circulation, especially when high emissions and significant warming occur towards the end of the century.
The new report also clearly pointed out that the warming we have experienced so far has changed many life support systems on Earth, and these changes are irreversible in the time frame of several centuries to thousands of years.
But the report pointed out that the biggest uncertainty in all climate change predictions is how humans will act.
If we take positive action now, many of the most terrifying effects of climate change can still be avoided.
Although the IPCC has been warning about the dangers of global warming for 30 years, governments have not yet taken the necessary actions to transition to clean energy and stop greenhouse gas emissions.
The report’s main collaborator and director of the Climate and Resilience Research Center of the University of Chile, Maisha Rojas, said, “Unless all greenhouse gases are reduced immediately, quickly and on a large scale, it is impossible to control global warming at 1.5°C. And".
For the first time, the sixth assessment report conducted a more detailed assessment of climate change from a regional perspective, including focusing on useful information to provide a basis for risk assessment, adaptation and other decision-making, and focusing on building a new framework to help integrate climate change. Information about natural changes (heat, cold, rain, drought, snow, wind, coastal floods, etc.) in order to make it meaningful to society and ecosystems.
The report reflects major advances in attribution science, that is, understanding the role of climate change in exacerbating certain weather and climate events, such as extreme heat waves and heavy rainfall events.
The report also shows that human actions may determine the future climate direction.
Evidence clearly shows that although other greenhouse gases and air pollutants can also affect the climate, carbon dioxide is still the main driver of climate change.
"Stabilizing the climate requires vigorous, rapid and continuous reduction of greenhouse gas emissions, and achieving net zero emissions of carbon dioxide. Reducing other greenhouse gas and air pollutant emissions, especially methane, is beneficial to health and climate." IPCC First Work Group co-chair Zhai Panmao said.
(Intern reporter Zhang Jiaxin, our reporter Fu Lili)Keywords: