当高收入国家及发展中国家的生产率增长时，社会根据生产效益提高了多少做出选择，这种选择会以提高消费水平或缩短工时的形式表现出来。例如，在最近的几十年间，西欧国家已经显著减少了工时（通过缩短每周工作时间和增加假期），但是美国还没有这样做。20世纪70年代早期，人们在西欧与在美国的工作时间几乎一样长。但是到了2005年，西欧比美国短了将近50%。
无论是选择缩短工时，还是提高消费，都对气候变化的速度产生了深远影响。许多研究表明，较短的工时与较低水平的温室气体排放相关，因此全球气候变化速度也随之降低。人们尚不清楚认识这两者间的复杂联系，但是目前可以理解的是，保持其他因素不变，低水平的消费可以减少温室气体排放。
本文预测了在本世纪剩余的时间内，以年均0.5%的速度缩短工时对气候变化的影响。我们发现，这样的工时变化会消除1/4至1/2的未锁定的全球变暖程度（由早在1990基准年前，存在在大气中的温室气体浓度所引起的气候变暖）。
值得注意的是，对于任何一个不平等现象严重或恶化的经济体，把缩短工时作为一种政策时，都将遇到更多困难。例如，在美国，1973—2007年间，前1%的家庭拥有近2/3的国民收入。在这类经济体中，为了减少工作时间，绝大部分员工不得不降低他们的生活水平。本文的分析假设，和过去一样，生产率增长的收益将在未来被更广泛的分享。
为了预估缩短工时的影响，本文援引了政府间气候变化专门委员会（IPCC）的四种“演示场景”，以及评估温室气体引起气候变化的模型。正如预期所料，全球变暖因缩短工时而减缓的程度，取决于基准情景，以及全球气温对温室气体排放的灵敏程度。
（“第一智库”网初步翻译，仅作参考）
Reduced Work Hours as a Means of Slowing Climate Change
As productivity grows in high-income, as well as developing countries, social choices will be made as to how much of the productivity gains will be taken in the form of higher consumption levels versus fewer work hours. In the last few decades, for example, western European countries have significantly reduced work hours (through shorter weekly hours and increased vacation time) while the United States has not. Western Europe had about the same hours worked per person as the U.S. in the early 1970s, but by 2005 they were about 50 percent less.
This choice between fewer work hours versus increased consumption has significant implications for the rate of climate change. A number of studies have found that shorter work hours are associated with lower greenhouse gas emissions and therefore less global climate change. The relationship between these two variables is complex and not clearly understood, but it is understandable that lowering levels of consumption, holding everything else constant, would reduce greenhouse gas emissions.
This paper estimates the impact on climate change of reducing work hours over the rest of the century by an annual average of 0.5 percent. It finds that such a change in work hours would eliminate about one-quarter to one-half of the global warming that is not already locked in (i.e. warming that would be caused by 1990 levels of greenhouse gas concentrations already in the atmosphere).
It is worth noting that the pursuit of reduced work hours as a policy alternative would be much more difficult in an economy where inequality is high and/or growing. In the United States, for example, just under two-thirds of all income gains from 1973–2007 went to the top 1 percent of households. In this type of economy, the majority of workers would have to take an absolute reduction in their living standards in order to work less. The analysis in this paper assumes that the gains from productivity growth will be more broadly shared in the future, as they have been in the past.
The analysis uses four “illustrative scenarios” from the Intergovernmental Panel on Climate Change (IPCC), and software from the Model for the Assessment of Greenhouse-gas Induced Climate Change to estimate the impact of a reduction in work hours. As would be expected, the amount of global warming that could be mitigated by reducing work hours depends on the baseline scenario, as well as the range of sensitivity of global temperatures to greenhouse gas emissions.
原文链接：http://www.cepr.net/documents/publications/climate-change-workshare-2013-02.pdf
