《2022年全球气候状况》临时报告（英）-世界气象组织.pdf

WMO Provisional State of the Global Climate 20222 Contents Highlights 3 Executive Summary . 3 Global Climate Indicators 5 Baselines . 5 Greenhouse gases . 5 Global temperature 6 Ocean heat content 8 Sea level 9 Marine heatwaves 10 Cryosphere 11 Sea ice . 11 Glaciers 12 Greenland ice sheet 13 Precipitation 14 Short-term climate drivers 15 High Impact Events . 16 Contributors 20 Data sets and methods . 21 3 Highlights Concentrations of the three main greenhouse gases – carbon dioxide, methane, and nitrous oxide – reached record highs in 2021. The annual increase in methane concentration was the highest on record. Real time data from specific locations show levels of the three gases continued to increase in 2022. Global mean temperature in 2022 is currently estimated to be 1.15 ± 0.13 °C above the 1850-1900 average. The eight years 2015 to 2022 are likely to be the eight warmest years on record, with 2022 most likely to be 5 th or 6 th warmest. La Niña conditions have continued with short interruptions since late 2020 and are expected to continue through late 2022. This would mark the third consecutive year of La Niña. Such a triple-dip La Niña is unusual and has kept global temperature low for the second year in a row. Sea level continued to rise in 2022, reaching a new record high. Since January 2020, global mean sea level has risen by nearly 10mm, approximately 10% of the overall rise in sea level since satellite measurements began in 1993. A low winter snowpack in 2021/22 combined with an exceptionally warm summer in Europe led to record glacier mass losses in Switzerland with 6% of the glacier ice volume lost between 2021 and 2022. Between 2001 and 2022 the volume of glacier ice in Switzerland decreased from 77 km 3 to 49 km 3 , a decline of more than a third. In east Africa, rainfall has been below average in four consecutive wet seasons, the longest sequence in 40 years with early indications that the current season could also be drier than average. Across the region, under the effects of the drought and other shocks, an estimated 18.4 to 19.3 million people have faced food Crisis or worse levels of acute food insecurity before June 2022. Record breaking rain in July and August led to extensive flooding in Pakistan. There were at least 1 700 deaths and 33 million people affected. 7.9 million people were displaced. Record breaking heatwaves affected China and Europe during the summer coupled with exceptionally dry conditions in places. The southern Africa region has been battered by a series of cyclones over two months, leading to a surge in the need for protection and shelter for hundreds of thousands of affected persons. Executive Summary The State of the Global Climate in 2022 is produced on an annual basis, complementing the most recent long assessment cycle provided by the sixth IPCC Assessment Report. This is the provisional version; the full and final report is expected to be published in March 2023. The report provides an authoritative voice on the current state of the climate using key climate indicators and reporting on extreme events and their impacts. Collecting and analysing data from these variables takes time— where 2022 data is not yet available, figures from 2021 are provided. In 2021, concentrations of the three main greenhouse gases – carbon dioxide, methane, and nitrous oxide – continued to reach record highs. The annual increase in methane concentration was the highest on record, which is especially significant given that methane is more than 25 times more potent than carbon dioxide at trapping heat in the atmosphere. Real time data from specific locations show levels of the three gases continued to increase in 2022. 4 The impact of increased concentration of GHG in the atmosphere is first and foremost on global temperatures. Global mean temperature in 2022 is currently estimated to be 1.15 ± 0.13 °C above the pre-industrial (1850-1900) average, likely making the past eight years (2015-2022) the warmest on record. Despite La Niña conditions keeping global temperature low for the second consecutive year, 2022 is still most likely to be 5 th or 6 th warmest year on record. Rising global temperatures have impacts on both the sea and on land. Antarctic sea-ice extent reached a record low in February 2022, at almost 1 million km 2 below the long-term mean. Meanwhile, the ocean continued to warm in 2021 and is expected to continue to warm well into the future. As the ocean warms, it expands, contributing to global sea level rise. Sea level continued to rise in 2022, reaching record high levels. Since January 2020, global sea level has risen nearly 10mm. Although this may not sound significant, it represents approximately 10% of the overall rise in sea level since satellite measurements began in 1993 in only 2 years, indicating that the rate of rise is speeding up. As temperatures rise, the continued melting of ice over land around the world is further contributing to accelerating sea level rise. The Greenland Ice Sheet ended with a negative total mass balance for the 26 th year in a row. Meanwhile, in Switzerland, 6% of the glacier ice volume was lost between 2021 and 2022, following low winter snowpack, dust coatings from the Sahara and an exceptionally warm summer in Europe. Between 2001 and 2022 the volume of glacier ice in Switzerland decreased from 77 km 3 to 49 km 3 , a decline of more than a third. Weather and climate extremes and their induced impacts are also exacerbated by rising global surface and sea temperatures. In East Africa, rainfall has been below average for four consecutive wet seasons, the longest sequence in 40 years. Across the region, under the effects of the drought and other shocks, an estimated 18.4-19.3 million people were facing acute food insecurity. In Pakistan, record breaking rain in July and August led to extensive flooding and approximately 1700 deaths, with 7.9 million people displaced, and 33 million people affected. Large parts of the northern hemisphere were exceptionally hot and dry in 2022. China had the most extensive and long-lasting heatwave since national records began and the second-driest summer on record. The Yangtze River at Wuhan reached its lowest recorded level for August. The temperature exceeded 40 °C in the United Kingdom for the first time, with a reading of 40.3 °C at Coningsby on 19 July, 1.6 °C above the previous national record. The heat extended as far north as Sweden, where 37.2 °C at Målilla on 21 July was the country’s highest since 1947. Drought conditions were at their most severe in August, when rivers including the Rhine, Loire and Danube fell to critically low levels. Taken together, these changes to the global climate are undermining the global ability to achieve sustainable development, directly impacting Sustainable Development Goals 1,2, 3, 6, 7, 10, 13, 14 and 15. However, the picture is far from complete. Significant gaps still exist for many key climate parameters, including ocean acidification (SDG 14) and methane emissions (SDG 13). Filling these gaps is essential for understanding the interconnections between climate change and development, and better addressing the disparities of where impacts are being felt, improving adaptation, and urging rapid mitigation. 5 Global Climate Indicators The global climate indicators provide an overview of changes in the climate system at the broadest scale 1 . This set of interlinked physical indicators connects the changing composition of the atmosphere with changes in energy in the climate system and the response of land, ocean, and ice. The global indicators are based on a wide range of data sets which are, in turn, based on multiple observing systems including both satellite and in situ data sources. For a complete list of datasets and information on baselines used in the report, see Data sets and methods. Baselines Baselines are periods of time, usually spanning one or more decades, that are used as a fixed benchmark against which conditions can be compared. Different baselines are used in this report, and these are specified in the text and figures. Where possible, the WMO climatological standard normal, 1981-2010, is used for consistent reporting. For some indicators, however, this is not possible owing to a lack of measurements during the early part of the period, or because a longer period is required to calculate representative statistics (for example, for precipitation). There are two exceptions. First, for the global mean temperature time series – and only for the global mean series – a reference period of 1850-1900 is used. This is the baseline used in the recent IPCC reports as a reference period for pre-industrial conditions and is relevant for understanding progress in the context of the Paris Agreement. Second, greenhouse gas concentrations can be estimated much further back in time using gas bubbles trapped in ice cores. The year 1750 is therefore used in this report to represent pre-industrial greenhouse gas concentrations. Greenhouse gases Atmospheric concentrations of greenhouse gases reflect a balance between emissions from human activities, natural sources, and sinks in the biosphere and ocean. Increasing levels of greenhouse gases in the atmosphere due to human activities are the major driver of climate change since the industrial revolution. Global average mole fractions of greenhouse gases – the concentration in the atmosphere – are calculated from in situ observations made at multiple sites in the Global Atmosphere Watch (GAW) Programme of WMO and partner networks. Real-time data from specific locations, including Mauna Loa 2 (Hawaii) and Kennaook/Cape Grim 3 (Tasmania) indicate that levels of CO 2, CH 4 and N 2O reached record levels in 2022. In 2021 – the latest year for which consolidated global figures are available – atmospheric levels of greenhouse gases reached new highs (Figure 1), with globally averaged surface mole fractions for carbon dioxide (CO 2) at 415.7 ± 0.2 parts per million (ppm), methane (CH 4) at 1908 ± 2 parts per billion (ppb) and nitrous oxide (N 2O) at 334.5 ± 0.1 ppb, respectively, 149%, 262% and 124% of pre-industrial (1750) levels. The increase in CO 2 from 2020 to 2021 was equal to that observed from 2019 to 2020, but higher than the average annual growth rate over the last decade. While the long-term increase in CO 2 is due to human emissions, year-to-year variations in the rate are largely associated with natural variability in the land and ocean carbon sinks. The record annual increase in 2016 was associated with the strong 2015/16 El Niño. 1 Trewin, B., Cazenave, A., Howell, S., Huss, M., Isensee, K., Palmer, M. D., Tarasova, O., the blue dots and line show the monthly averages. Bottom row: the growth rates representing increases in successive annual means of mole fractions for CO 2 in parts per million per year are shown as grey columns (left), CH 4 in parts per billion per year (centre) and N 2O in parts per billion per year (right) (Source: WMO Global Atmosphere Watch). Global temperature The global mean temperature so far in 2022 has been 1.15 [1.02 to 1.28] °C above the 1850-1900 average (Figure 2, 2022 figures are based on data from January to September). If the current anomaly continues to the end of the year, the six data sets used in the analysis would place 2022 as either the 5 th or 6 th warmest year on record (from 1850), and in each case marginally warmer than 2021. The eight years 2015 to 2022 are likely to be the eight warmest years on record in all data sets. 4 Lunt, M. F., Palmer, P. I., Feng, L., Taylor, C. M., Boesch, H., and Parker, R. J. (2019): An increase in methane emissions from tropical Africa between 2010 and 2016 inferred from satellite data, Atmos. Chem. Phys., 19, 14721–14740, https://doi.org/10.5194/acp-19-14721-2019. 5 Feng, L., Palmer, P. I., Zhu, S., Parker, R. J., Hall, D. M.; Ulbrich, U. Artificial Intelligence Reconstructs Missing Climate Information. Nature Geoscience 2020, 13 (6), 408–413. https://doi.org/10.1038/s41561-020-0582-5. Bracketed values indicate the 5%–95% confidence range.