There has been much confusion ahead of the next round of international negotiations on climate change, which start at the end of this month, over whether the United States has shifted its position on the inclusion of a temperature target in a new treaty that is due to be agreed by 2015. But the signs are that while the United States is still not leading by example, the Obama administration has at least not resorted to the obstructionism of its predecessor.
Last week, the chief climate change negotiator at the State Department, Todd Stern, attracted criticism when he discussed during a speech at Dartmouth College the prospects for a new international treaty that "builds in the capacity for modification over time", but appeared to question the role of a target to reduce global greenhouse gas emissions to avoid global warming of more than two centigrade degrees:
"This kind of flexible, evolving legal agreement cannot guarantee that we meet a two degree goal, but insisting on a structure that would guarantee such a goal will only lead to deadlock. It is more important to start now with a regime that can get us going in the right direction and that is built in a way maximally conducive to raising ambition, spurring innovation, and building political will."
Some commentators interpreted his remarks as a call to abandon the two degree target, forcing the State Department to issue a clarifying statement from Stern:
"There have been some incorrect reports about comments I made in a recent speech relating to our global climate goal of holding the increase in global average temperature to below two degrees Celsius. Of course, the US continues to support this goal; we have not changed our policy. My point in the speech was that insisting on an approach that would purport to guarantee such a goal - essentially by dividing up carbon rights to the atmosphere - will only lead to stalemate given the very different views countries would have on how such apportionment should be made. My view is that a more flexible approach will give us a better chance to actually conclude an effective new agreement and meet the goal we all share."
Stern's statement appears to be a pragmatic acknowledgement of the current limited ambition among countries to cut emissions by enough to achieve the two degree target.
Countries first began to acknowledge the importance of a temperature target at the annual United Nations climate change conference in 2009, when the hastily agreed Copenhagen Accord included a pledge to "reduce global emissions so as to hold the increase in global temperature below 2 degrees Celsius". That commitment has been reaffirmed at subsequent conferences in Cancún and Durban.
However, the latest study by the United Nations Environment Programme shows that current pledges for action to cut or limit emissions by 2020 are not consistent with a reasonable chance of achieving the two degree target. This means either that global emissions would need to be reduced much more quickly after 2020, which is likely to be more difficult and expensive, or that global emissions would probably lead global warming to exceed two centigrade degrees.
Given the current levels of emissions and the uncertainties in matching a pathway for global annual emissions to a future change in temperature, most analyses have assumed that the target is a reduction that offers about a 50 per cent chance of avoiding a rise in global average temperature of more than two centigrade degrees. That would require global annual emissions of greenhouse gases to be cut from the current level of about 50 billion tonnes of carbon-dioxide-equivalent to 44 billion tonnes in 2020, below 35 billion tonnes in 2030 and much less than 20 billion tonnes in 2050. In essence, global emissions need to be reduced from an average of about 7 tonnes per head on average today to about 2 tonnes per capita by the middle of the century, assuming the population by then will be around nine billion, with rich countries making a cut of about 80 per cent.
Todd Stern's argument is that countries are unlikely to increase their 2020 ambitions enough over the next three years to be in line with the two degree target, but that this should not be allowed to prevent a new international agreement on climate change. This could be regarded as a pragmatic approach that is designed to increase the chances of securing global action and that countries could at some later point aim to increase their emissions reductions.
But one should also remember that the United States is one of the countries that is clearly failing at present to reduce its emissions quickly enough. Although President Obama's first budget in February 2009 included a target of reducing his country's annual emissions by 14 per cent by 2020 compared with 1990, and by 83 per cent by 2050, Congress has not passed the legislation required to realise it. In 2010, the United States emitted 6.8 billion tonnes of greenhouse gases, equivalent to average per capita annual emissions of about 22 tonnes. Future emissions by the United States are not projected to be in line with President Obama's target. An analysis by the Energy Information Administration has shown that current policies, even with increased replacement of coal with natural gas for electricity generation, are likely to mean energy-related emissions of carbon dioxide will be almost the same in 2035 as they were in 2010, and some 12 per cent higher than they were in 1990.
Still, at least President Obama is not adopting the same cynical strategy on climate change as his predecessor. One of George W. Bush's first acts as President was to announce that the United States would not honour its signature to the Kyoto Protocol and the commitment to reduce its emissions by 7 per cent by 2012 compared with 1990. In fact, annual emissions by the time President Bush left office were 13.9 per cent higher than in 1990.
Not only did the United States not show leadership on climate change under President Bush, but it was often obstructive during international negotiations, famously leading a delegate from Papua New Guinea, Kevin Conrad, to issue this appeal at the 2007 United Nations summit:
"And I would ask the United States. We ask for your leadership. We seek your leadership. But if for some reason you are not willing to lead, leave it to the rest of us. Please get out of the way."
But we may yet see the United States revert to blocking tactics if Mitt Romney, the likely Republican challenger, beats Barack Obama in November's Presidential election. Last October, Romney told a rally in Pittsburgh: "My view is that we don't know what's causing climate change on this planet. And the idea of spending trillions and trillions of dollars to try to reduce CO2 emissions is not the right course for us." His official campaign website states: "As president, Mitt Romney will eliminate the regulations promulgated in pursuit of the Obama administration's costly and ineffective anti-carbon agenda.".
If the United States does elect a climate change 'sceptic' to be President in November, an international agreement to avoid global warming of more than two centigrade degrees may become very remote prospect indeed.
Bob Ward is policy and communications director at the Grantham Research Institute on Climate Change and the Environment at London School of Economics and Political Science.