The world's leading scientists have projected that in the coming decades, there would be increasing heat waves, longer warm seasons and shorter cold seasons.
全球顶级科学家预测，在未来几十年里，暖季将变得更长，冷季将更短，同时极端高温等极端天气将变得更加频繁。

According to the latest Intergovernmental Panel on Climate Change (IPCC) report , climate change is also intensifying the water cycle, bringing more intense rainfall and associated flooding, as well as more intense drought in many regions.
联合国政府间气候变化专门委员会发布的这份报告表示，气候变化将加速水循环，在带来更多强降雨、洪涝灾害的同时也会导致许多地区更加严重的干旱。

【知识点】

政府间气候变化专门委员会（Intergovernmental Panel on Climate Change，IPCC）于1988年由世界气象组织（World Meteorological Organization）和联合国环境署（United Nations Environment Programme）联合创建，旨在提供有关气候变化的科学技术和社会经济认知状况、气候变化原因（the drivers of climate change）、潜在影响（ its impacts and future risks）和应对策略（how adaptation and mitigation can reduce those risks）的综合评估。

目前IPCC正处于第六次评估周期（the Sixth Assessment cycle），此次发布的报告是IPCC第一工作小组的评估报告，由来自60多个国家的200多名科学家撰写，其中引用的相关独立研究超过1.4万个。报告全面评估了2013年第五次评估报告发布以来世界气候变化科学研究方面取得的重要进展。

报告明确指出：

Human activity was “unequivocally” the cause of rapid changes to the climate, including sea level rises, melting polar ice and glaciers, heat waves, floods and droughts.
毫无疑问，人类活动是海平面上升、极地冰川融化、高温、洪水以及旱灾等气候快速变化事件的原因。

Many of the changes observed in the climate are unprecedented in thousands, if not hundreds of thousands of years, and some changes already set in motion -- such as continued sea level rise -- are irreversible over hundreds to thousands of years.
我们观察到的很多气候变化是几千年或者几十万年来前所未有的，而海平面不断上升这样已经发生的变化不可逆转，在未来几百年到几千年间都将持续发生。

Sea levels are expected to rise 2 to 3 meters by 2300 even if warming is kept below 2 degrees, but could reach 5 to 7 meters or higher if warming continues unabated.
就算全球升温控制在2摄氏度之内，到2300年，海平面仍然会上升2到3米，而如果全球变暖的趋势没有缓解，则海平面到时可能会上升5到7米。

【知识点】

《巴黎协定（Paris Agreement）》确立了2020年后国际社会合作应对气候变化的基本框架，提出把全球平均气温较工业化前水平升高幅度控制在2摄氏度之内（hold the global average temperature increase to well below 2 degrees C），并为把升温控制在1.5摄氏度之内而努力（pursue efforts to limit it to 1.5 degrees C）。

The authors believe that 1.5C will be reached by 2040 in all scenarios. If emissions aren't slashed in the next few years, this will happen even earlier.
报告作者认为，无论情况如何发展，到2040年，全球升温将达到1.5摄氏度。如果未来几年不大力减排，这一天会来得更早。

全球升温1.5摄氏度会怎么样？

报告举了个例子：

Extreme heat waves expected once every 50 years without any global heating are already happening every decade. With 1.5C warming, these will happen about every 5 years; with 2C, every 3.5 years; and with 4C, once every 15 months. More heating also means more disruptions to the monsoon rains on which billions depend for food.
没有全球升温影响的情况下，原本每50年发生一次的极端高温天气现在每10年就有一次。升温1.5摄氏度以后，这样的极端天气大约每5年会出现一次；升温2摄氏度时，每3.5年出现一次；升温4摄氏度时，每15个月出现一次。高温天气增多同时意味着对雨季的影响增多，而全球几十亿人的食物也会受到影响。

我们该怎么做？

The scientists are hopeful that if we can cut global emissions in half by 2030 and reach net zero by the middle of this century, we can halt and possibly reverse the rise in temperatures.
科学家们认为，如果我们在2030年之前将全球碳排放减半，并在本世纪中叶达到净零排放，就有可能止住甚至扭转升温的步伐。

联合国秘书长古特雷斯表示：

[This report] is a code red for humanity. The alarm bells are deafening, and the evidence is irrefutable: greenhouse gas emissions from fossil fuel burning and deforestation are choking our planet and putting billions of people at immediate risk.
（这份）报告是对人类发出的红色警报。这个警报声振聋发聩，报告中列出的证据无可辩驳：石油燃烧排放的温室气体和森林砍伐让地球窒息，置十几亿人于迫近的危险之中。

All nations, especially the G20 and other major emitters, need to join the net zero emissions coalition and reinforce their commitments with credible, concrete and enhanced Nationally Determined Contributions and policies before COP26 in Glasgow.
所有国家，尤其是二十国集团成员国以及其他主要排放大国，要加入净零排放的联合行动中，在格拉斯哥第26届联合国气候变化大会之前拿出可靠的、具体的、进一步完善的国家自主贡献目标承诺和政策。

【知识点】

国家自主贡献（nationally determined contributions）指根据《联合国气候变化框架公约（the United Nations Framework Convention on Climate Change）》缔约方会议相关决定，提出的各国应对气候变化的强化行动和措施（enhanced actions and measures on climate change）。

There must be no new coal plants built after 2021. OECD countries must phase out existing coal by 2030, with all others following suit by 2040. Countries should also end all new fossil fuel exploration and production, and shift fossil fuel subsidies into renewable energy. By 2030, solar and wind capacity should quadruple and renewable energy investments should triple to maintain a net zero trajectory by mid-century.
2021年后不得再新建煤炭工厂。经济合作与发展组织成员国必须在2030年之前停止使用煤炭，其他国家2040年之前达到这一目标。各国还应该停止所有新的石油勘探和生产项目，将原有的石油行业补贴用于可再生能源。到2030年，太阳能和风能的产能应达到现在的四倍，可再生能源投资应该达到目前的三倍，才能在本世纪中叶走上净零排放的轨道。