世界气象组织新发布的《2021年气候状况报告》是继世界顶级气候科学家今年发表的类似的令人震惊的出版物之后，继续填补了日益严峻的画面的重要细节。该报告由几十位专家汇编，重点关注气候变化的关键指标正在继续展开，并特别描绘了整个2021年进入未知领域的几个指标的走向。
尽管有拉尼娜的冷却效应，2021年的全球平均温度比工业化前水平高出约1.11°C，这证明我们正朝着《巴黎协定》中规定的1.5°C的极限前进，以避免气候变化的最灾难性影响。据作者称，过去七年是有记录以来最热的七年，突出了一个整体的变暖趋势，自20世纪80年代以来，每个十年都比上一个十年更温暖。
世界气象组织秘书长Petteri Taalas说：“我们看到另一个历史上最热的年份只是时间问题。我们的气候正在我们眼前发生变化。由人类引起的温室气体所截留的热量将使地球在未来的许多代中变暖。海平面上升、海洋热量和酸化将持续数百年，除非发明了从大气中清除碳的手段。一些冰川已经达到了不可逆转的地步，这将对一个已经有20多亿人经历水压力的世界产生长期影响。”
报告中概述的惊人发现包括大气中温室气体浓度的全球新高，目前全球二氧化碳浓度为413.2ppm，为工业化前水平的149%。科学家们以前曾警告说，这种积累正在以危险的速度加速，从20世纪60年代的300ppm的低水平，以每年约0.9 ppm的速度增加，在2010年和2019年之间每年增加约2.4 ppm – 350 ppm是专家认为的安全水平。夏威夷的一个监测站的早期数据表明，2022年4月的浓度实际上达到了420.23ppm。
“报告强调，大气中的二氧化碳现在已经在2022年超过了420ppm，”澳大利亚麦考瑞大学的兼职研究员Tom Mortlock 博士评论道。“从这个角度来看，南极洲的冰芯记录表明，大气中的二氧化碳在150至300ppm之间自然波动。我们现在可能比地球历史上最后一百万年的二氧化碳自然水平高出40%，而这一切都发生在过去的150年里。现在明确无误的是，最近这段时间的变暖是由人类产生的温室气体排放所推动的。如果我们想避免气候变化的最坏影响，我们必须根据巴黎协议将升温限制在1.5℃。”
虽然气候变化对整个陆地环境有许多影响，但其大部分影响可以通过海洋的反应方式看到，《气候状况报告》从多个方面阐明了这一点。2013年至2021年期间，全球平均海平面平均每年增加4.5毫米（0.18英寸），大约是1993年至2002年的两倍，这是因为冰原的融化率增加，使其在2021年达到创纪录的水平。
海洋吸收了人类活动产生的大约23%的二氧化碳，而当它发生化学反应时，会使海水酸化。这不仅对大堡礁这样的海洋环境构成了严重的威胁，在那里严重的珊瑚礁白化现象不断发生，而且随着pH值的下降，海洋吸收这些二氧化碳的能力也在下降，根据作者的说法，它们现在已经达到了历史最低点。
他们写道：“人们非常有信心认为，公海表面pH值现在是至少26000年以来的最低值，目前的pH值变化率至少是自那时以来前所未有的。”
除了这些影响之外，海洋和地球一样，也在不断变暖。数据描绘了在过去20年中，海洋温度的增长特别强烈，并在2021年创下了新高。2021年大部分海洋都出现了强烈的海洋热浪，上层2000米（6500英尺）继续变暖，而且这种温暖渗透到越来越深的地方。
除了这些新的基准，气候变化继续推动极端天气事件，如北美和地中海的破纪录热浪，中国和西欧的严重洪灾以及非洲和亚洲的严重干旱。作者还指出，在格陵兰岛冰原加速融化的情况下，该冰原的最高点Summit Station出现了有史以来第一次降雨记录。
澳大利亚格里菲斯大学科学、技术和社会荣誉教授Ian Lowe说：“世界气象组织的新报告让人读起来很不舒服。它记录了气候变化的加速。过去的七年是有史以来最热的七年，随着海洋变暖，海平面上升速度加快，世界海洋变得更加酸化。除非我们采取紧急行动，减少化石燃料的燃烧，否则将没有机会拯救大堡礁。随着更严重的热浪、洪水事件和野火的发生，世界已经在为科学变得清晰以来几十年的不作为付出高昂的代价。”
世界气象组织的全球气候状况报告是作为将于今年完成的IPCC第六次评估报告的补充而提出的。它还将作为今年晚些时候在埃及举行的联合国气候变化大会（COP27）的正式文件和谈判资源。
The World Meteorological Organization’s newly released Climate report 2021 continues to fill in important details of the increasingly grim picture, following a similar shocking publication by the world’s top climate scientists this year. The report, compiled by dozens of experts, continues to focus on key indicators of climate change, with particular emphasis on the direction of several indicators that have entered uncharted territory throughout 2021.
Despite La Nina’s cooling effect, the global average temperature in 2021 is about 1.11 °C higher than pre-industrial levels, proving that we are moving towards the 1.5 °C limit set out in the Paris Agreement to avoid the most catastrophic effects of climate change. According to the authors, the past seven years have been the hottest on record, highlighting an overall warming trend, with each decade warmer than the last since the 1980s.
Petteri Taalas, Secretary-General of the World Meteorological Organization, said: “it is only a matter of time before we see another of the hottest years in history. Our climate is changing before our eyes. The heat trapped by human-induced greenhouse gases will warm the earth for many generations to come. Sea-level rise, ocean heat and acidification will continue for hundreds of years unless means are invented to remove carbon from the atmosphere. Some glaciers have reached irreversible levels, which will have a long-term impact on a world where more than 2 billion people are already experiencing water stress. “
The startling findings outlined in the report include the world’s highest concentration of greenhouse gases in the atmosphere, which currently stands at 413.2ppm, 149 per cent of pre-industrial levels. Scientists have previously warned that this accumulation is accelerating at a dangerous rate, from the low level of 300ppm in the 1960s to about 0.9 ppm a year, an increase of about 2.4 ppm-350 ppm per year between 2010 and 2019, a level that experts believe is safe. Early data from a monitoring station in Hawaii showed that concentrations actually reached 420.23ppm in April 2022.
“the report stresses that carbon dioxide in the atmosphere now exceeds that of 420ppm in 2022,” commented Dr Tom Mortlock, an adjunct researcher at Macquarie University in Australia. From this point of view, ice core records in Antarctica show that carbon dioxide in the atmosphere fluctuates naturally between 150 and 300ppm. We may now be 40% higher than the natural level of carbon dioxide in the last 1 million years of Earth’s history, all of which has happened in the last 150 years. It is now clear that the recent warming has been driven by human-generated greenhouse gas emissions. If we want to avoid the worst effects of climate change, we must limit warming to 1.5 degrees Celsius in accordance with the Paris Agreement. “
Although climate change has many impacts on the terrestrial environment as a whole, most of its impacts can be seen through the response of the oceans, as illustrated in the Climate State report in many ways. Between 2013 and 2021, the global average sea level increased by an average of 4.5 mm (0.18 inches) per year, about double the rate between 1993 and 2002, as the melting rate of the ice sheet increased, bringing it to a record level in 2021.
The ocean absorbs about 23% of the carbon dioxide produced by human activities, and when it reacts, it acidifies the water. Not only does this pose a serious threat to the marine environment such as the Great Barrier Reef, where severe coral reef bleaching continues to occur, but as the pH value drops, so does the ocean’s ability to absorb this carbon dioxide, according to the authors. They have now reached an all-time low.
“people are very confident that the surface pH of the high seas is now the lowest in at least 26,000 years, and that the current rate of change in pH is unprecedented, at least since then,” they wrote. “
In addition to these effects, the oceans, like the earth, are warming. The data depict a particularly strong increase in ocean temperatures over the past 20 years, reaching a new high in 2021. There will be strong ocean heat waves in most oceans in 2021, and the upper layer 2000 meters (6500 feet) continues to warm, and the warmth seeps deeper and deeper.
In addition to these new benchmarks, climate change continues to drive extreme weather events, such as record-breaking heat waves in North America and the Mediterranean, severe floods in China and Western Europe, and severe droughts in Africa and Asia. The authors also point out that Summit Station, the highest point of the Greenland ice sheet, recorded the first rainfall in history as the ice sheet accelerated its melting.
Ian Lowe, emeritus professor of science, technology and society at Griffith University in Australia, said: “the new WMO report is very uncomfortable to read. It records the acceleration of climate change. The past seven years have been the hottest on record, and as the oceans warm and sea levels rise faster, the world’s oceans become more acidified. Unless we take urgent action to reduce the burning of fossil fuels, there will be no chance to save the Great Barrier Reef. With more severe heat waves, floods and wildfires, the world is already paying a high price for decades of inaction since science became clear. “
The World Meteorological Organization’s global climate report is presented as a supplement to the sixth assessment report of the IPCC, which will be completed this year. It will also serve as an official document and negotiation resource for the United Nations Climate change Conference (COP27) to be held in Egypt later this year.
