4月22日晚，应美国总统拜登邀请，国家主席习近平在北京以视频方式出席领导人气候峰会，并发表题为《共同构建人与自然生命共同体》的重要讲话。新华社记者 黄敬文 摄

4月22日是世界地球日，2021年的地球日将极不寻常。全球仍在和新冠疫情大决战，全球气候变化的“灰犀牛”更是加速到来，国际气候政治大博弈进入全新阶段。美国总统拜登将在4月22-23日主持召开气候领导人峰会，这为全球气候治理进程增添了巨大不确定性。拜登召集的地球日气候峰会将围绕哪些议题，又将如何影响全球气候治理进程，备受全球瞩目。

争取全球气候治理领导权。拜登在竞选期间就强调美国必须“再次领导”全球气候治理进程，并将气候议题作为其竞选的“王牌”。他上任第一天即签署系列行政令，并重返《巴黎协定》，但目前尚未公布其2030年国家自主贡献目标（NDC）。拜登政府急于在地球日期间召开全球气候领导峰会的战略目的，就是要在重返气候治理进程后赢得新的话语权和主导力，以4月22日世界地球日为契机，借助全球气候危机状态和碳中和大趋势，以所谓“气候正义”旗号推动全球“碳中和”新议程。美国总统气候特使约翰·克里称，“召开本次峰会对于确保美国在2021年真正弥补过去四年的损失时间及在联合国气候大会的作用至关重要”。重返《巴黎协定》后召集盟友和伙伴国家塑造新的国际气候治理进程，重塑美国对全球气候新秩序的领导权是拜登政府的战略核心。

2℃还是1.5℃？《巴黎协定》目标是将全球平均温度升幅控制在2℃以内，并继续争取把温度升幅限定在1.5℃。由于《巴黎协定》是以NDC形式自下而上地开展减排承诺，2℃目标显然比1.5℃目标给予发展中国家的发展空间更大。但是，拜登政府却想借地球日峰会将全球温控目标提高到1.5℃。克里在年初慕尼黑安全大会上反复称，“如果要防止气候危机带来的最严重后果，我们必须将地球变暖的温度限制在1.5摄氏度以内”。由于1.5℃目标深受广大小岛国集团支持，再加上今年极端天气灾害放大了全球气候危机的国际舆论，此次峰会美国将极力说服参会国将全球气候治理进程目标从2℃提高到1.5℃。

美国更新NDC。美国国家气候顾问吉娜·麦卡锡1月27日在白宫新闻发布会上表示，美国新政府将确保美国的NDC在世界地球日峰会前公布。美国原计划在年底的联合国气候变化缔约方大会第26次会议（COP26）前公布其新的NDC，但为了增强美国在国际气候治理中的底气和对其他国家要价的砝码，它大概率将在此次峰会前公布。克里近期也表示，保持1.5℃极限，制定到2050年实现碳中和路线图是关键。因此，美国新的NDC将锚定1.5℃和2050年碳中和两大目标，并以此对发展中排放大国进行对等施压。

重启主要经济体能源与气候论坛（MEF）。拜登上台后一直计划重启MEF，该论坛是2009年4月美国前总统奥巴马发起的，参与国由占世界温室气体排放量80%的17个国家组成。克里近期在多个场合表示要重启该论坛，称“拜登总统已指示我和我们的团队在4月22日峰会前举行一次世界所有主要排放国峰会，我们将特别要求所有主要排放国在前往格拉斯哥COP26时提高气候行动雄心”。MEF原来的主要作用是协调主要国家共同推进《巴黎协定》谈判，而拜登政府此次重启MEF的侧重点是在全球推动“碳中和”目标广泛协议，从而逐渐摆脱《巴黎协定》和《联合国气候变化框架公约》中的“共同但有区别责任原则”，特别是对发展中排放大国际施加新约束。

重建绿色联盟。美国国务卿布林肯近期访问北约总部时表示，气候变化为美国与同盟国面临的全球性三大危机之一，要重新构建美国的同盟体系。拜登在发布气候行政令时也强调，“本届政府的政策是考虑气候因素应成为美国外交政策和国家安全的重要组成部分”。重建以应对气候危机为重点的绿色联盟，将成为拜登政府重塑以“气候安全”为中心的国际权力体系的支柱。为此，克里已于3月8-10日前往伦敦、布鲁塞尔和巴黎，与欧洲国家一道紧密协调气候政策立场，并与英国政府代表协调将于年底在英国格拉斯哥举行的COP26。美国两党领袖也都把重建美欧合作关系视为领导全球应对气候变化的支柱，欲重整美欧气候合作纽带“雄心联盟”。克里在慕尼黑安全大会上还表示，拜登将在4月峰会期间与G7、G20、北极理事会协调政策立场。另外，拜登政府还计划在“印太战略”框架下与印度加强合作。

当前，全球气候安全与气候治理正处在关键期，需要国际社会在联合国框架下推进《巴黎协定》的全面实施。中美两国已发表应对气候危机联合声明，这为全球气候治理进程注入了正能量。地球日气候峰会也应秉持公平原则、共同但有区别的责任原则和各自能力原则，推动落实《巴黎协定》和《联合国气候变化框架公约》。发达经济体在减排行动上应率先做出表率，兑现承诺，承担应有的历史责任，这样才能推动国际气候治理走向公平与正义。环球同此凉热，气候变化是人类在21世纪将要面对的最大共同安全威胁，要战胜这一巨大挑战需要以共同、综合、合作、可持续的全球安全观来推动全球的安全、和平和可持续发展。

At the invitation of U.S. President Joe Biden, Chinese President Xi Jinping attends the Leaders Summit on Climate via video link and delivers an important speech titled "For Man and Nature: Building a Community of Life Together" in Beijing, capital of China, April 22, 2021. (Xinhua/Huang Jingwen)

April 22 was World Earth Day, and it was an unusual one, as the world is still fighting a crucial battle against the coronavirus pandemic.As the gray rhinoceros of global climate change approaches at increasing speed, the great game of international climate politics has entered a new stage. U.S. President Joe Biden hosted the Leaders Summit on Climate from April 22 to 23, adding significant uncertainty to the global climate governance process. Biden's Earth Day summit will affect global climate governance and attract global attention.

Attempt to regain leadership in global climate governance.During his political campaign for the White House, Biden stressed the need for the United States to lead the global climate governance process and made the climate issue his trump card. On his first day in office, he signed a series of executive orders and returned to the Paris Agreement. But he has not announced the 2030 targets of America's national determined contributions, known as NDCs. The strategic purpose of the administration's rush to convene a climate summit on Earth Day was to gain back the say and leadership in the climate governance process, thus promoting a new global carbon neutrality agenda under the banner of “climate justice" by riding on the crisis situation and the carbon neutrality trend.John Kerry, Biden's special presidential envoy for climate, talked about the critical role of the summit in helping the U.S. make up for lost time over the past four years and protect its role at COP26, to be held in Glasgow, Scotland, toward the end of the year. Bringing together allies and partners together concurrently with America's return to the Paris Agreement — to shape a new international climate governance process and rebuild American leadership in the new global climate order — lies at the heart of the Biden strategy.

2 C or 1.5 C?The Paris Agreement aims to hold the global average temperature increase below 2 C, or even better to below 1.5 C. As the Paris Agreement represents a bottom-up approach of emission reduction commitments in the form of NDCs, the 2-degree target offers greater development space for developing countries than the 1.5-degree one. The Biden administration, however, wanted to use the Earth Day Summit to apply the higher target of 1.5 degrees.“If we want to prevent the worst consequences of the climate crisis, we have to limit the planet's warming to 1.5 degrees Celsius,” Kerry told the Munich Security Conference earlier this year.Given that the 1.5 C target is strongly supported by a group of small island states and that this year's extreme weather disasters have magnified the international climate crisis, the U.S. will try its best to persuade participants to target 2 C instead of 1.5 C.

Update of NDCs.Gina McCarthy, the U.S. national climate adviser, said at a White House briefing on Jan. 27 that the new administration would make sure to announce the NDCs before the Earth Day summit. The U.S. had planned to unveil its new NDCs before COP26. To strengthen America's position in international climate governance and its leverage over other countries, it's highly probable that this will have occurred before the summit. Kerry also said recently that holding the global temperature increase within 1.5 C would be key to developing a road map to carbon neutrality by 2050. Therefore, the U.S. will anchor its NDCs to the 1.5 C level and promise carbon neutrality by 2050. It will then exert pressure on major developing emitters to do the same.

Major Economies Forum on Energy and Climate.Since taking office, Biden has been planning to restart the MEF, initiated by former President Obama in April 2009. It involves 17 countries that account for 80 percent of the world's total greenhouse gas emissions.Kerry has on several recent occasions mentioned the MEF's reactivation, saying that he and his team had been instructed by President Biden to hold a summit of all the world's major emitters before April 22 and that the U.S. would specifically ask all the major emitters to increase their climate action ambitions when they go to COP26.The MEF's primary role was to coordinate major countries in advancing the Paris Agreement negotiations. Now the Biden administration is focusing on a broad global agreement on carbon neutrality targets, thereby gradually moving away from the principle of common but differentiated responsibilities of the Paris Agreement and the UNFCCC and imposing new restrictions on major developing emitters.

Rebuilding a green coalition.During a recent visit to the NATO headquarters, Secretary of State Antony Blinken called climate change one of the top three global crises facing the American alliance, and it necessitates a restructuring of the alliance system. While issuing the relevant executive order, Biden also stressed that “climate considerations shall be an essential element of U.S. foreign policy and national security.”Rebuilding a green coalition to tackle the climate crisis will be a pillar of the administration's effort to reshape the international system of power centered on climate security. To that end, Kerry traveled to London, Brussels and Paris in March to closely coordinate climate policy positions with Europe and on COP26 with the United Kingdom. Leaders of both parties in the U.S. also see the reestablishment of cooperation with Europe as underpinning American leadership in the global effort to deal with climate change and want to renew the climate ambition alliance with Europe.Kerry also told the Munich Security Conference that Biden would coordinate policy positions with the G7, G20 and Arctic Council during the April summit. In addition, the administration plans to strengthen cooperation with India within the Indo-Pacific strategy framework.

Global climate security and climate governance are now at a critical stage. The international community needs to push for the full implementation of the Paris Agreement within the framework of the United Nations. China and the U.S. recently issued a joint statement addressing the climate crisis, injecting energy into the global climate governance process. The Earth Day summit should also promote the implementation of the Paris Agreement and the UNFCCC in accordance with the principles of equity, differentiated responsibilities and respective capabilities. Developed economies should take the lead, honor their own commitments and shoulder their historical responsibilities in cutting emissions, thus steering international climate governance toward equity and justice.As mankind lives on the same — and only — planet, climate change poses the biggest common security threat of the 21st century. To overcome this enormous challenge, countries will have to promote global security, peace and sustainable development with a new vision of common, comprehensive, cooperative and sustainable security.