In order to reflect the hot events in the field of climate change scientific research at home and abroad and the frontier scientific progress in the field of climate change at home and abroad, reflect the interaction between climate change scientific research and policy formulation, and provide scientific and technological support for the construction of ecological civilization and the implementation of the dual carbon target on the mainland. The Climate Change Center of the China Meteorological Administration launched the "Top Ten Scientific Events of Climate Change in 2021" selection activity in early 2022, organizing experts to invite academicians of the Chinese Academy of Sciences and the Chinese Academy of Engineering, members of the National Climate Change Expert Committee, and well-known experts in the field of climate change in China (including the main author of the IPCC assessment report and the main author of the national climate change assessment report) to select the candidate events on the basis of preliminary selection, and the selection was determined" The Top 10 Science Events on Climate Change in 2021 (in order of votes) are:
1. The IPCC publishes the AR6 WGI assessment report, Climate Change 2021: Natural Science Foundations, which notes that many of the observed changes are unprecedented
2. The Glasgow Climate Change Conference reached the Glasgow Climate Agreement, which emphasizes the importance of science in policymaking to address climate change
3. Climatologists Makoto Shuku and Hasselman won the 2021 Nobel Prize in Physics, and the first prize in the field of atmospheric and marine sciences
4. The World Health Organization has issued a Special Report on Climate Change and Health, which recommends that priority be given to climate policies with maximum health benefits
5. The Chinese government and the scientific and technological community have worked together to promote carbon peaking and carbon neutrality, and the white paper, blue book and green paper on climate change have been released successively
6. Tropical cyclones may expand into the mid-latitudes as extreme events occur frequently, record-breaking heat waves increase
7. Climate reversal factors can trigger high risks, and the Atlantic Current System may be approaching the climatic critical point
8. The China Meteorological Administration has built the first national greenhouse gas observation network in the mainland
9. The latest climate commitments of countries will reduce global temperature rise to 1.8°C by the end of the 21st century
10. Global CARBON dioxide emissions rebounded sharply in 2021, and fossil fuel CO emissions have almost returned to pre-outbreak levels
1. The IPCC publishes the AR6 WGI assessment report, Climate Change 2021: Natural Science Foundations, which notes that many of the observed changes are unprecedented
In August 2021, the United Nations Intergovernmental Panel on Climate Change (IPCC) released the First Working Group report of the Sixth Assessment Report, Climate Change 2021: Natural Science Foundations. Scientists have been observing changes in various regions of the globe and the entire climate system, many of which have been observed that are unprecedented in thousands or even hundreds of thousands of years, and some changes that have begun, such as continuous sea-level rise, are irreversible in hundreds to thousands of years, the report said. The report highlights that in the decade from 2011 to 2020, global surface temperatures were 1.09°C higher than between 1850 and 1900, a level never seen since the Ice Age 125,000 years ago, and the hottest five years since 1850 was recorded. Global warming could reach or exceed the 1.5°C threshold over the next 20 years; climate change is bringing many different changes to different regions that will all intensify as global warming intensifies; and many of the most dire effects of climate change can still be avoided if positive action is taken now.
2. The Glasgow Climate Change Conference reached the Glasgow Climate Agreement, which emphasizes the importance of science in policy development to address climate change
The 2021 United Nations Climate Change Conference, held in Glasgow, UK, from 31 October to 12 November, culminated in the Glasgow Climate Agreement, which covers eight dimensions: science, adaptation, adaptation finance, mitigation, funding, technology and capacity building, loss and damage, implementation and cooperation. The Glasgow Climate Agreement, which includes science as its first part, points out the importance of the best available science for effective climate action and policymaking, and emphasizes the urgency of addressing climate change from a scientific perspective. The Glasgow Climate Agreement draws on the latest findings of the IPCC's Sixth Assessment Report, stressing that achieving a temperature rise at a certain level requires rapid, deep and sustained reductions in global CO2 emissions and significant reductions in other non-CO2 greenhouse gas emissions such as methane.
3. Climatologists Makoto Shuku and Haselman won the 2021 Nobel Prize in Physics, and the first prize in atmospheric and marine sciences
The 2021 Nobel Prize in Physics was awarded to two climatologists, Shuko Andeh Hasselman, and a theoretical physicist. The 2021 Nobel Prize in Physics recognizes Makoto and Haselman for their outstanding contributions to "physical simulation, quantification of variability and reliable prediction of global warming" of the Earth's climate. The radiation-convection model established by Shiro Manabe is a milestone work for understanding climate warming. For the first time, various problems of radiation transmission were comprehensively solved, and combined with convection adjustment, a numerical model for reliably calculating the increase in CO caused by global warming was established. Hasselmann innovatively used climate models and observational data to establish an optimal fingerprint method for detecting and attributing climate change. Optimal fingerprinting emphasizes not only temporal changes in the climate system, but also the spatial distribution of global climate change. Haselmann's optimal fingerprinting method has been used to show that the rise in atmospheric temperature is due to CO emissions from humans. It is based on optimal fingerprinting and recently developed climate models that the IPCC WGI AR6 concludes that "there is no doubt that human activities have caused warming of the atmosphere, oceans and land." "The winning of two climatologists, Zhen Pan Shuhao and Hasselman, will surely further attract the attention of the international community to the problem of global warming.
4. The World Health Organization has issued a Special Report on Climate Change and Health, which recommends that priority be given to climate policies with the greatest health benefits
In October 2021, the World Health Organization (WHO) released a special report on climate change and health, setting out the position of the global health community on climate action, namely that a growing body of research shows that there are many inextricable links between climate and health. The report recommends to governments on global action to address climate change and maximize human health: put health and social justice at the heart of the UN climate negotiations; prioritize measures to address climate change with maximum health, social and economic benefits; guide the transition to renewable energy sources to reduce air pollution, especially from coal burning; promote sustainable, healthy urban design and transport systems, with an emphasis on walking, cycling and public transport. The report highlights that unprecedented extreme weather events and other climate change events are causing increasing damage to human life and health, and that countries must make strong commitments to climate change to achieve a healthy green recovery in the wake of COVID-19.
5. The Chinese government and the scientific and technological community have worked together to promote carbon peaking and carbon neutrality, and the white paper, blue book and green paper on climate change have been released
In August 2021, the Climate Change Center of the China Meteorological Administration released the Blue Book of Climate Change in China (2021), pointing out that the first 20 years of the 21st century were the warmest period in China's century. The 2021 Blue Book presents the latest monitoring information on the state of climate change in China and the world, providing scientific data and basic scientific and technological support information services for national and regional responses to climate change. In October 2021, the white paper "China's Policies and Actions to Address Climate Change (2021)" was released to promote the realization of carbon peaking and carbon neutrality goals as scheduled. The "1+N" action plan for the implementation of the dual carbon target in the mainland has been released one after another, which provides a strong impetus for the comprehensive green transformation of economic and social development and the realization of high-quality development. The Green Paper on Climate Change (2021), released in December 2021, focuses on China's carbon neutrality goals, analyzes the challenges and opportunities and paths for achieving carbon peaking and carbon neutrality in mainland China from different fields, different sectors and different entities, and demonstrates the policies and actions of green, low carbon and climate adaptation.
The extreme weather events of 2021 significantly broke long-standing records. Winter storm "Uri" hit most of North America, and the lowest temperatures in many parts of North America exceeded historical extremes. Globally, many countries and regions experience abnormally high temperatures, and the Northern Hemisphere is in the midst of extreme heat. The results of a 2021 study by Swiss researchers on the probability of a record-breaking heat wave varying with global warming show that under the high emission scenario, the probability of a record-breaking extreme heat wave in 2021-2050 is 2 to 7 times that of the past 30 years, and it will be 3 to 21 times higher in 2051-2080. In the mid-latitudes of the Northern Hemisphere, these events will occur every 6 to 37 years from 2051 to 2080. A 2021 study by Yale University predicts that tropical cyclones (hurricanes and typhoons) in the 21st century may occur at a larger latitude than in the past 3 million years, with more tropical cyclones found in the mid-latitudes. This finding means that tropical cyclones pose a higher risk in global warming. Hurricane Henry, which made landfall in Connecticut in 2021, could be a precursor to such a storm.
7. Climate reversal factors can raise a high risk, and the Atlantic Ocean Current System may be approaching the climatic tipping point
Climate reversals such as melting ice sheets, changes in ocean currents, and rainforest deforestation can interact with each other. The latest research suggests that the interaction between climate reversal factors can eventually trigger abrupt changes when global warming is slower than expected. For example, abrupt changes in ocean circulation often occur with moderate warming (less than 2 °C). The Atlantic Ocean's warped inverted circulation transports warm water from the tropics north to the ocean surface and cold water south to the bottom of the ocean, closely linked to relatively mild temperatures in Europe. A 2021 study by the University of Copenhagen in Denmark and the Potsdam Institute for Climate Impact Research in Germany suggested that this major current in the Atlantic Ocean may have lost stability in the 20th century. Studies have shown that the Atlantic Ocean's current warped inversion circulation is at its weakest state in more than 1,000 years. Weakened dynamic stability means that the Atlantic oceanian inverted circulation has approached a critical threshold beyond which a substantial and irreversible transition to a weak mode may occur. The Atlantic ocean's warped circulation also affects the global weather system, and its potential collapse could have serious consequences – cooling Europe significantly and having a strong impact on the tropical monsoon system.
In December 2021, the China Meteorological Administration released the country's first national greenhouse gas observation network directory. This marks the completion of the first greenhouse gas observation network in China after nearly 40 years of construction. The completion of the greenhouse gas observation network will enhance China's climate change monitoring and assessment capabilities, and continue to provide scientific data support for the mainland's carbon peaking and carbon neutrality actions. The list of greenhouse gas observation networks released this time includes 60 stations covering the main climate key areas of the country and focusing on high-precision observations, which are composed of national atmospheric background stations, national climate observatories and national and provincial applied meteorological (greenhouse gas) observation stations. Its observation elements cover seven categories of greenhouse gases stipulated in the Kyoto Protocol, including CO, CH, NO, hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride and nitrogen trifluoride.
9. The latest climate commitments of countries will reduce global temperature rise to 1.8°C by the end of the 21st century
In December 2021, the European Commission's Joint Research Centre released the Global Energy and Climate Outlook 2021: Towards Climate Neutrality, which assesses the impact of updated Nationally Determined Contributions (NDCs) and long-term net-zero emissions targets on temperature-rising levels. The report notes that global temperature rise will exceed 3 °C by 2100 in the current policy context, and only the emission reduction target promised by the NDC scenario will reach 2.6 °C by 2100, while achieving the long-term net zero emission target will reduce the global temperature rise to 1.8 °C by 2100. In the current policy context, global greenhouse gas emissions will peak around 2040, while under the long-term net-zero path, global greenhouse gas emissions will peak around 2023 and stabilize in the middle of the 21st century.
10. Global carbon dioxide emissions rebounded sharply in 2021, and fossil fuel CO emissions have almost returned to pre-outbreak levels
The Global Carbon Budget 2021 report released in November 2021 notes that CO emissions fell by 5.4% in 2020 due to COVID-19 constraints, but rose by about 4.9% (4.1% to 5.7%) in 2021 to 36.4 billion tonnes, bringing emissions almost back to 2019 levels. This shows that the "green recovery" promised by governments after the epidemic has not been fulfilled. Strong growth in coal and natural gas use is the main reason for the increase in emissions in 2021, while oil is growing more slowly. Although emissions from the U.S. and Europe in 2021 were down from 2019 levels, India's emissions rose by about 4.4 percent. On current trends, the report predicts that global carbon emissions will continue to rise in 2022.
(Guangming Daily all-media reporter Cui Xingyi)
Source: Guangming Daily all-media reporter Cui Xingyi
Editor-in-charge: Wang Zimo
Editor: Zhang Yongqun, Sun Xiaoting