International climate change mitigation requires leadership 

The September 25 commentary states that "this must change soon if we are to avert a scope and rapidity of climate change never before witnessed in human history". 

The majority of the nations attending high-level summit on climate change hosted by UN Secretary-General Ban Ki-moon are "powerless" to stop the growth in emissions, claim the authors. 

Participation of a "relatively small group of nations", comprising the US, China, Russia and India (responsible for over half of the world's emissions) and another six (with the top ten accounting for over two-thirds), is "critical to the success of any mitigation strategy", they say. 

Any agreement "must involve enforceable commitments that reflect the scale of the threat". Moreover, without strong action by the US and China, "the world will continue its plunge towards climate catastrophe", they claim. 

The US strategy of voluntary reductions is not working and it needs to enforce more effective climate legislation now, insist Russell and Sawin – outlining advantages that put the country in a potential leading position on climate change:

• Extensive experience with cap-and-trade programmes; 
• Decades of emissions measurement, reporting, and enforcement experience; 
• A strong and entrepreneurial industry for developing renewable energy and energy efficiency technologies; 
• A vibrant investment community and clear internal examples of the potential for energy efficiency improvements to meet demand growth. 
• Ageing capital stock that invites replacement with efficient, low-carbon technology. 

Meanwhile, China must "develop the institutional ability to monitor and reduce emissions" because its "capacity to enforce a near-term emissions reduction commitment is […] limited". This is of utmost importance because if China’s emissions growth continues, "it will nullify any carbon reductions achieved by other countries". 

The authors conclude that it is the major emitters that need to take action according to their responsibilities and capabilities, while a US commitment to binding emissions reduction targets is "crucial to advance the world towards effective mitigation". 

Industrial countries have the technological and economic capacity to "drastically" reduce their emissions, whereas developing countries have "tremendous opportunities to forge new development paths" that "break from the past", they add.