美國還能領導氣候行動嗎
Amid much optimism the UN declared last week the world was on course to pass the threshold necessary to put the Paris climate change deal into effect.
上週，聯合國(UN)頗爲樂觀地宣佈，全球即將邁過讓巴黎氣候變化協議生效所需要達到的門檻。
More than 55 countries have joined the agreement, representing about half of all global emissions.
超過55個國家加入了該協議，它們的溫室氣體排放量約佔全球的一半。
Yet that milestone could almost instantly be undone if the US courts reject President Barack Obama’s clean energy plan.
然而，如果美國法庭否決巴拉克•奧巴馬(Barack Obama)的清潔能源計劃，這一里程碑幾乎瞬間就會倒塌。
A group of Republican states and energy companies say Mr Obama’s methods, which aim to cut US carbon emissions by more than a quarter within a decade, are unconstitutional.
能源企業以及共和黨控制的多個州表示，奧巴馬使美國碳排放量在10年內減少逾四分之一所採用的方法是違憲的。
The hearings start on Tuesday.
聽證會於週二開始。
At question is the courts’ view of the scope of Washington’s regulatory powers.
法庭對聯邦政府監管權範圍的看法是問題所在。
At stake is US leadership on climate change — and the viability of the Paris deal itself.
但其結果將關係到美國在氣候變化方面的領導力以及巴黎氣候變化協議本身的存續。
The objections are deceptively abstruse.
反對的理由看上去深奧，其實不然。
Opponents of Mr Obama’s plan say he has overstepped his powers by requiring US states to cut their carbon emissions.
反對奧巴馬計劃的人士表示，奧巴馬要求各州減排是越權之舉。
They claim this over-interprets the Clean Air Act, which gives Washington’s Environmental Protection Agency the power to regulate local pollutants, such as mercury and sulphur.
他們聲稱，這過度解讀了《清潔空氣法案》(Clean Air Act)，該法案賦予美國環保署(Environmental Protection Agency)監管本地污染物的權力，例如汞和硫磺。
They also say Mr Obama’s plan violates the US constitution which bans the federal government from taking control of state resources.
他們還表示，奧巴馬的計劃違反了美國憲法，因爲憲法禁止聯邦政府控制州的資源。
Courts have ruled that carbon dioxide is a pollutant and thus within the EPA’s scope.
法庭已裁定，二氧化碳是污染物，因此在環保署的監管範圍之內。
But the plaintiffs say Mr Obama is misusing even this authority by setting broad mandates, which gives states the latitude to decide how to reach their goals.
但原告們表示，奧巴馬即便對這項權力也使用不當，他設定了寬泛的任務框架，讓各州自由決定如何達到它們的減排目標。
Under this narrow reading, Mr Obama should only have scope to shut down precisely defined sources of pollution.
根據這種狹隘的解讀，奧巴馬只應有權關閉精確界定的污染源。
The objections are unconvincing both on practical and legal grounds.
無論從現實還是法律的角度來看，這些反對意見都是沒有說服力的。
The president is surely right to say that, within a broad framework, the states are best placed to draw up their plans since they have a clearer grasp than Washington of local energy needs.
奧巴馬錶示，在一個廣泛框架下，由各州擬定各自的計劃是最合適的，因爲它們比聯邦政府更瞭解本地能源需求。
Some may choose to keep their coal-fired plants open and make up ground with stringent energy efficiency codes.
奧巴馬這麼說無疑是對的。一些州可能選擇讓燃煤發電廠繼續運營，代之以嚴格的能效規定。
Others may wish to do the opposite.
還有一些州可能希望採取相反的措施。
Either way, if the objections are upheld, Mr Obama would be forced to spell out case by case how states should comply with the mandate.
不管是哪種做法，如果上述反對意見得到支持，奧巴馬將被迫一個一個地提出各州應如何執行減排任務的計劃。
The result would be the same.
結果是一樣的。
But the means would be far more intrusive.
但做法會更具干預性。
It is possible the court could throw out the plan altogether on constitutional grounds.
法庭有可能以憲法爲由徹底否決該計劃。
But that is unlikely.
但可能性並不大。
The legal basis for US federal leadership has been established.
美國聯邦政府的領導權是有法律依據的。
Even if Mr Obama’s plan survives the courts intact, it would be rendered moot were Donald Trump elected in November.
即便奧巴馬的計劃完整無缺地得到法庭允許，但如果唐納德•特朗普(Donald Trump)在11月當選，它也就毫無意義了。
Mr Trump has vowed to pull the US out of the Paris deal and reverse Mr Obama’s executive actions to reduce carbon emissions.
特朗普發誓將讓美國退出巴黎氣候變化協議，並廢除奧巴馬在減排方面的行政做法。
By contrast, any modification of Mr Obama’s plan would be manageable were Hillary Clinton to win.
相比之下，如果希拉里•克林頓(Hillary Clinton)當選，即便她對奧巴馬計劃有所修改也會是可控的。
Her administration could reconfigure the means to cut US emissions without diluting the target.
她的政府可能會在不降低目標的情況下調整減排手段。
Both the legal challenge and the high-stakes presidential election underline the fragility of US leadership on global warming.
法律挑戰以及關係重大的總統大選都突顯了在全球氣候變暖問題上，美國領導力的脆弱性。
That will remain true as long as Congress refuses to pass legislation that would put a price on carbon. The chances of that happening remain slim in the near future.
只要美國國會拒絕通過徵收碳稅法律——在近期內立法的可能性很小——這種局面就不會改變。
That should not stop supporters of market-based reform from making the case more forcefully on Capitol Hill.
這不應阻止支持市場改革的人士在美國國會提出更有力的理由。
The US is on course to fulfil about two-thirds of its carbon emission cuts by 2025 because of its switch to shale gas and fracking, and stricter vehicle emission rules.
由於轉向頁岩氣和壓裂法並實施了更嚴格的汽車排放規定，美國有望到2025年完成大約三分之二的減排目標。
All this is happening anyway.
不管怎樣，這一點是現實情況。
What is at stake is not the shifts in US energy patterns but the question of American leadership.
目前重要的不是美國能源模式的轉變而是美國領導力的問題。
Other countries will act more decisively if US is seen to be taking the lead.
如果看到美國發揮表率作用，其他國家將採取更果斷的行動。
