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℃。”
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.